Maybe fix handling of 7byte and 10byte uid cards

LICENSE

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+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.

README.md

@@ -1,4 +1,4 @@
-# I237 Hardware Programming
+# I237 Door Access program
 
 This here is my repository for hardware programming course at
 Estonian IT College that is based around a
@@ -39,3 +39,24 @@ git checkout lab02
 ```
 
 Don't forget to `make clean` after each checkout!
+
+# License
+
+```Text
+Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+
+This file is part of I237 Door Access program.
+
+I237 Door Access is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+I237 Door Access is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+```

doc/arduino-mega-rfid-rc522-wiring.markdown

@@ -0,0 +1,25 @@
+# Arduino Mega RFID-RC522 wiring
+
+## Introduction
+
+**NB! RFID-RC522 requires only 3.3 V DC input voltage. Never connect it to 5V input.**
+
+<div class=pagebreak></div>
+
+## Wiring illustration
+
+![arduino-mega-rfid-rc522-wiring.png](arduino-mega-rfid-rc522-wiring.png)
+
+## Wiring table
+
+| Signal | ATMega2560 port and pin | Arduino Mega 2560 pin | 5V to 3V converter | RFID-RC522 | Wire colour in illustration |
+| --- | --- | --- | --- | --- |  --- |
+| Slave select | PORTB 0 | 53 | - | SDA | White |
+| SPI clock | PORTB 1 | 52 | - | SCK | Orange |
+| Master out slave in | PORTB 2 | 51 | - | MOSI | Green |
+| Master in slave out | PORTB 3 | 50 | - | MISO | Yellow |
+| RF522 reset | PORTL 0 | 49 | - | RST | Brown |
+| Ground | GND | GND | GND | GND | Black |
+| 5 V DC | - | 5V | VIN | - | Red |
+| 3,3 V DC | - | - | VOUT | 3.3 V | Red |
+

lib/matejx_avr_lib/README.txt

@@ -0,0 +1,2 @@
+
+Library homepage is at www.randomport.com

lib/matejx_avr_lib/hwdefs.h

@@ -0,0 +1,20 @@
+#ifndef MAT_HWDEFS_H
+#define MAT_HWDEFS_H
+
+#define DDR(x) (*(&x - 1))
+#define PIN(x) (*(&x - 2))
+
+#define MFRC522_SS_PORT     PORTB
+#define MFRC522_SS_BIT      0
+
+#define MFRC522_RST_PORT    PORTL
+#define MFRC522_RST_BIT     0
+
+#define SCK_DDR     DDRB
+#define SCK_BIT     DDB1
+#define MOSI_DDR    DDRB
+#define MOSI_BIT    DDB2
+#define MISO_DDR    DDRB
+#define MISO_BIT    DDB3
+
+#endif

lib/matejx_avr_lib/hwdefs_minimal.h

@@ -0,0 +1,7 @@
+#ifndef MAT_HWDEFS_H
+#define MAT_HWDEFS_H
+
+	#define DDR(x) (*(&x - 1))
+	#define PIN(x) (*(&x - 2))
+
+#endif

lib/matejx_avr_lib/mfrc522.h

@@ -0,0 +1,253 @@
+#ifndef MFRC522_h
+#define MFRC522_h
+
+	#include <inttypes.h>
+
+	typedef uint8_t bool;
+	typedef uint8_t byte;
+	typedef uint16_t word;
+
+	// MFRC522 registers. Described in chapter 9 of the datasheet.
+	// When using SPI all addresses are shifted one bit left in the "SPI address byte" (section 8.1.2.3)
+	enum PCD_Register {
+		// Page 0: Command and status
+		//						  0x00			// reserved for future use
+		CommandReg				= 0x01 << 1,	// starts and stops command execution
+		ComIEnReg				= 0x02 << 1,	// enable and disable interrupt request control bits
+		DivIEnReg				= 0x03 << 1,	// enable and disable interrupt request control bits
+		ComIrqReg				= 0x04 << 1,	// interrupt request bits
+		DivIrqReg				= 0x05 << 1,	// interrupt request bits
+		ErrorReg				= 0x06 << 1,	// error bits showing the error status of the last command executed
+		Status1Reg				= 0x07 << 1,	// communication status bits
+		Status2Reg				= 0x08 << 1,	// receiver and transmitter status bits
+		FIFODataReg				= 0x09 << 1,	// input and output of 64 byte FIFO buffer
+		FIFOLevelReg			= 0x0A << 1,	// number of bytes stored in the FIFO buffer
+		WaterLevelReg			= 0x0B << 1,	// level for FIFO underflow and overflow warning
+		ControlReg				= 0x0C << 1,	// miscellaneous control registers
+		BitFramingReg			= 0x0D << 1,	// adjustments for bit-oriented frames
+		CollReg					= 0x0E << 1,	// bit position of the first bit-collision detected on the RF interface
+		//						  0x0F			// reserved for future use
+
+		// Page 1:Command
+		// 						  0x10			// reserved for future use
+		ModeReg					= 0x11 << 1,	// defines general modes for transmitting and receiving
+		TxModeReg				= 0x12 << 1,	// defines transmission data rate and framing
+		RxModeReg				= 0x13 << 1,	// defines reception data rate and framing
+		TxControlReg			= 0x14 << 1,	// controls the logical behavior of the antenna driver pins TX1 and TX2
+		TxASKReg				= 0x15 << 1,	// controls the setting of the transmission modulation
+		TxSelReg				= 0x16 << 1,	// selects the internal sources for the antenna driver
+		RxSelReg				= 0x17 << 1,	// selects internal receiver settings
+		RxThresholdReg			= 0x18 << 1,	// selects thresholds for the bit decoder
+		DemodReg				= 0x19 << 1,	// defines demodulator settings
+		// 						  0x1A			// reserved for future use
+		// 						  0x1B			// reserved for future use
+		MfTxReg					= 0x1C << 1,	// controls some MIFARE communication transmit parameters
+		MfRxReg					= 0x1D << 1,	// controls some MIFARE communication receive parameters
+		// 						  0x1E			// reserved for future use
+		SerialSpeedReg			= 0x1F << 1,	// selects the speed of the serial UART interface
+
+		// Page 2: Configuration
+		// 						0x20			// reserved for future use
+		CRCResultRegH			= 0x21 << 1,	// shows the MSB and LSB values of the CRC calculation
+		CRCResultRegL			= 0x22 << 1,
+		// 						  0x23			// reserved for future use
+		ModWidthReg				= 0x24 << 1,	// controls the ModWidth setting?
+		// 						  0x25			// reserved for future use
+		RFCfgReg				= 0x26 << 1,	// configures the receiver gain
+		GsNReg					= 0x27 << 1,	// selects the conductance of the antenna driver pins TX1 and TX2 for modulation
+		CWGsPReg				= 0x28 << 1,	// defines the conductance of the p-driver output during periods of no modulation
+		ModGsPReg				= 0x29 << 1,	// defines the conductance of the p-driver output during periods of modulation
+		TModeReg				= 0x2A << 1,	// defines settings for the internal timer
+		TPrescalerReg			= 0x2B << 1,	// the lower 8 bits of the TPrescaler value. The 4 high bits are in TModeReg.
+		TReloadRegH				= 0x2C << 1,	// defines the 16-bit timer reload value
+		TReloadRegL				= 0x2D << 1,
+		TCounterValueRegH		= 0x2E << 1,	// shows the 16-bit timer value
+		TCounterValueRegL		= 0x2F << 1,
+
+		// Page 3:Test Registers
+		// 						  0x30			// reserved for future use
+		TestSel1Reg				= 0x31 << 1,	// general test signal configuration
+		TestSel2Reg				= 0x32 << 1,	// general test signal configuration
+		TestPinEnReg			= 0x33 << 1,	// enables pin output driver on pins D1 to D7
+		TestPinValueReg			= 0x34 << 1,	// defines the values for D1 to D7 when it is used as an I/O bus
+		TestBusReg				= 0x35 << 1,	// shows the status of the internal test bus
+		AutoTestReg				= 0x36 << 1,	// controls the digital self test
+		VersionReg				= 0x37 << 1,	// shows the software version
+		AnalogTestReg			= 0x38 << 1,	// controls the pins AUX1 and AUX2
+		TestDAC1Reg				= 0x39 << 1,	// defines the test value for TestDAC1
+		TestDAC2Reg				= 0x3A << 1,	// defines the test value for TestDAC2
+		TestADCReg				= 0x3B << 1		// shows the value of ADC I and Q channels
+		// 						  0x3C			// reserved for production tests
+		// 						  0x3D			// reserved for production tests
+		// 						  0x3E			// reserved for production tests
+		// 						  0x3F			// reserved for production tests
+	};
+
+	// MFRC522 comands. Described in chapter 10 of the datasheet.
+	enum PCD_Command {
+		PCD_Idle				= 0x00,		// no action, cancels current command execution
+		PCD_Mem					= 0x01,		// stores 25 bytes into the internal buffer
+		PCD_GenerateRandomID	= 0x02,		// generates a 10-byte random ID number
+		PCD_CalcCRC				= 0x03,		// activates the CRC coprocessor or performs a self test
+		PCD_Transmit			= 0x04,		// transmits data from the FIFO buffer
+		PCD_NoCmdChange			= 0x07,		// no command change, can be used to modify the CommandReg register bits without affecting the command, for example, the PowerDown bit
+		PCD_Receive				= 0x08,		// activates the receiver circuits
+		PCD_Transceive 			= 0x0C,		// transmits data from FIFO buffer to antenna and automatically activates the receiver after transmission
+		PCD_MFAuthent 			= 0x0E,		// performs the MIFARE standard authentication as a reader
+		PCD_SoftReset			= 0x0F		// resets the MFRC522
+	};
+
+	// Commands sent to the PICC.
+	enum PICC_Command {
+		// The commands used by the PCD to manage communication with several PICCs (ISO 14443-3, Type A, section 6.4)
+		PICC_CMD_REQA			= 0x26,		// REQuest command, Type A. Invites PICCs in state IDLE to go to READY and prepare for anticollision or selection. 7 bit frame.
+		PICC_CMD_WUPA			= 0x52,		// Wake-UP command, Type A. Invites PICCs in state IDLE and HALT to go to READY(*) and prepare for anticollision or selection. 7 bit frame.
+		PICC_CMD_CT				= 0x88,		// Cascade Tag. Not really a command, but used during anti collision.
+		PICC_CMD_SEL_CL1		= 0x93,		// Anti collision/Select, Cascade Level 1
+		PICC_CMD_SEL_CL2		= 0x95,		// Anti collision/Select, Cascade Level 1
+		PICC_CMD_SEL_CL3		= 0x97,		// Anti collision/Select, Cascade Level 1
+		PICC_CMD_HLTA			= 0x50,		// HaLT command, Type A. Instructs an ACTIVE PICC to go to state HALT.
+		// The commands used for MIFARE Classic (from http://www.nxp.com/documents/data_sheet/MF1S503x.pdf, Section 9)
+		// Use PCD_MFAuthent to authenticate access to a sector, then use these commands to read/write/modify the blocks on the sector.
+		// The read/write commands can also be used for MIFARE Ultralight.
+		PICC_CMD_MF_AUTH_KEY_A	= 0x60,		// Perform authentication with Key A
+		PICC_CMD_MF_AUTH_KEY_B	= 0x61,		// Perform authentication with Key B
+		PICC_CMD_MF_READ		= 0x30,		// Reads one 16 byte block from the authenticated sector of the PICC. Also used for MIFARE Ultralight.
+		PICC_CMD_MF_WRITE		= 0xA0,		// Writes one 16 byte block to the authenticated sector of the PICC. Called "COMPATIBILITY WRITE" for MIFARE Ultralight.
+		PICC_CMD_MF_DECREMENT	= 0xC0,		// Decrements the contents of a block and stores the result in the internal data register.
+		PICC_CMD_MF_INCREMENT	= 0xC1,		// Increments the contents of a block and stores the result in the internal data register.
+		PICC_CMD_MF_RESTORE		= 0xC2,		// Reads the contents of a block into the internal data register.
+		PICC_CMD_MF_TRANSFER	= 0xB0,		// Writes the contents of the internal data register to a block.
+		// The commands used for MIFARE Ultralight (from http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf, Section 8.6)
+		// The PICC_CMD_MF_READ and PICC_CMD_MF_WRITE can also be used for MIFARE Ultralight.
+		PICC_CMD_UL_WRITE		= 0xA2		// Writes one 4 byte page to the PICC.
+	};
+
+	// MIFARE constants that does not fit anywhere else
+	enum MIFARE_Misc {
+		MF_ACK					= 0xA,		// The MIFARE Classic uses a 4 bit ACK/NAK. Any other value than 0xA is NAK.
+		MF_KEY_SIZE				= 6			// A Mifare Crypto1 key is 6 bytes.
+	};
+
+	// PICC types we can detect. Remember to update PICC_GetTypeName() if you add more.
+	enum PICC_Type {
+		PICC_TYPE_UNKNOWN		= 0,
+		PICC_TYPE_ISO_14443_4	= 1,	// PICC compliant with ISO/IEC 14443-4
+		PICC_TYPE_ISO_18092		= 2, 	// PICC compliant with ISO/IEC 18092 (NFC)
+		PICC_TYPE_MIFARE_MINI	= 3,	// MIFARE Classic protocol, 320 bytes
+		PICC_TYPE_MIFARE_1K		= 4,	// MIFARE Classic protocol, 1KB
+		PICC_TYPE_MIFARE_4K		= 5,	// MIFARE Classic protocol, 4KB
+		PICC_TYPE_MIFARE_UL		= 6,	// MIFARE Ultralight or Ultralight C
+		PICC_TYPE_MIFARE_PLUS	= 7,	// MIFARE Plus
+		PICC_TYPE_TNP3XXX		= 8,	// Only mentioned in NXP AN 10833 MIFARE Type Identification Procedure
+		PICC_TYPE_NOT_COMPLETE	= 255	// SAK indicates UID is not complete.
+	};
+
+	// Return codes from the functions in this class. Remember to update GetStatusCodeName() if you add more.
+	enum StatusCode {
+		STATUS_OK				= 1,	// Success
+		STATUS_ERROR			= 2,	// Error in communication
+		STATUS_COLLISION		= 3,	// Collission detected
+		STATUS_TIMEOUT			= 4,	// Timeout in communication.
+		STATUS_NO_ROOM			= 5,	// A buffer is not big enough.
+		STATUS_INTERNAL_ERROR	= 6,	// Internal error in the code. Should not happen ;-)
+		STATUS_INVALID			= 7,	// Invalid argument.
+		STATUS_CRC_WRONG		= 8,	// The CRC_A does not match
+		STATUS_MIFARE_NACK		= 9		// A MIFARE PICC responded with NAK.
+	};
+
+	// A struct used for passing the UID of a PICC.
+	typedef struct {
+		byte		size;			// Number of bytes in the UID. 4, 7 or 10.
+		byte		uidByte[10];
+		byte		sak;			// The SAK (Select acknowledge) byte returned from the PICC after successful selection.
+	} Uid;
+
+	// A struct used for passing a MIFARE Crypto1 key
+	typedef struct {
+		byte		keyByte[MF_KEY_SIZE];
+	} MIFARE_Key;
+
+	// Member variables
+	//Uid uid;								// Used by PICC_ReadCardSerial().
+
+	// Size of the MFRC522 FIFO
+	//static const byte FIFO_SIZE = 64;		// The FIFO is 64 bytes.
+
+	//-----------------------------------------------------------------------------------
+	// Functions for setting up the Arduino
+	//-----------------------------------------------------------------------------------
+	void MFRC522_init(void);
+	void setSPIConfig(void);
+
+	//-----------------------------------------------------------------------------------
+	// Basic interface functions for communicating with the MFRC522
+	//-----------------------------------------------------------------------------------
+	void PCD_WriteRegister(byte reg, byte value);
+	void PCD_WriteRegister2(byte reg, byte count, byte *values);
+	byte PCD_ReadRegister(byte reg);
+	void PCD_ReadRegister2(byte reg, byte count, byte *values, byte rxAlign);
+	void setBitMask(unsigned char reg, unsigned char mask);
+	void PCD_SetRegisterBitMask(byte reg, byte mask);
+	void PCD_ClearRegisterBitMask(byte reg, byte mask);
+	byte PCD_CalculateCRC(byte *data, byte length, byte *result);
+
+	//-----------------------------------------------------------------------------------
+	// Functions for manipulating the MFRC522
+	//-----------------------------------------------------------------------------------
+	byte PCD_Init(void);
+	byte PCD_Reset(void);
+	void PCD_AntennaOn(void);
+
+	//-----------------------------------------------------------------------------------
+	// Functions for communicating with PICCs
+	//-----------------------------------------------------------------------------------
+	byte PCD_TransceiveData(byte *sendData, byte sendLen, byte *backData, byte *backLen, byte *validBits, byte rxAlign, bool checkCRC);
+	byte PCD_CommunicateWithPICC(byte command, byte waitIRq, byte *sendData, byte sendLen, byte *backData, byte *backLen, byte *validBits, byte rxAlign, bool checkCRC);
+
+	byte PICC_RequestA(byte *bufferATQA, byte *bufferSize);
+	byte PICC_WakeupA(byte *bufferATQA, byte *bufferSize);
+	byte PICC_REQA_or_WUPA(	byte command, byte *bufferATQA, byte *bufferSize);
+	byte PICC_Select(Uid *uid, byte validBits);
+	byte PICC_HaltA(void);
+
+	//-----------------------------------------------------------------------------------
+	// Functions for communicating with MIFARE PICCs
+	//-----------------------------------------------------------------------------------
+	byte PCD_Authenticate(byte command, byte blockAddr, MIFARE_Key *key, Uid *uid);
+	void PCD_StopCrypto1(void);
+	byte MIFARE_Read(byte blockAddr, byte *buffer, byte *bufferSize);
+	byte MIFARE_Write(byte blockAddr, byte *buffer, byte bufferSize);
+ 	byte MIFARE_Decrement(byte blockAddr, long delta);
+	byte MIFARE_Increment(byte blockAddr, long delta);
+ 	byte MIFARE_Restore(byte blockAddr);
+ 	byte MIFARE_Transfer(byte blockAddr);
+	byte MIFARE_Ultralight_Write(byte page, byte *buffer, byte bufferSize);
+
+	//-----------------------------------------------------------------------------------
+	// Support functions
+	//-----------------------------------------------------------------------------------
+	byte PCD_MIFARE_Transceive(	byte *sendData, byte sendLen, bool acceptTimeout);
+	const char *GetStatusCodeName(byte code);
+	byte PICC_GetType(byte sak);
+	const char *PICC_GetTypeName(byte type);
+	void PICC_DumpToSerial(Uid *uid);
+	void PICC_DumpMifareClassicToSerial(Uid *uid, byte piccType, MIFARE_Key *key);
+	void PICC_DumpMifareClassicSectorToSerial(Uid *uid, MIFARE_Key *key, byte sector);
+	void PICC_DumpMifareUltralightToSerial(void);
+	void MIFARE_SetAccessBits(byte *accessBitBuffer, byte g0, byte g1, byte g2, byte g3);
+
+	//-----------------------------------------------------------------------------------
+	// Convenience functions - does not add extra functionality
+	//-----------------------------------------------------------------------------------
+	bool PICC_IsNewCardPresent(void);
+	bool PICC_ReadCardSerial(Uid* uid);
+
+/*
+private:
+	byte _chipSelectPin;		// Arduino pin connected to MFRC522's SPI slave select input (Pin 24, NSS, active low)
+	byte _resetPowerDownPin;	// Arduino pin connected to MFRC522's reset and power down input (Pin 6, NRSTPD, active low)
+	byte MIFARE_TwoStepHelper(byte command, byte blockAddr,	long data);
+*/
+
+#endif

lib/matejx_avr_lib/spi.c

@@ -0,0 +1,98 @@
+/**
+
+SPI methods are not interrupt driven - they wait until SPI operation completes.
+If you're using CMT and would prefer switching to another task while SPI operation
+is in progress, you can define SPI_USE_CMT in swdefs.h. This requires CMT_MUTEX_FUNC.
+
+Also, SS (CS) is not controlled by these methods. It's the responsibility of the user.
+
+@file		spi.c
+@brief		SPI routines
+@author		Matej Kogovsek (matej@hamradio.si)
+@copyright	LGPL 2.1
+@note		This file is part of mat-stm32f1-lib
+*/
+
+#include <inttypes.h>
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+#include "spi.h"
+#include "hwdefs.h"
+
+#ifdef SPI_USE_CMT
+	#warning SPI using cmt
+	#include "cmt.h"
+	struct cmt_mutex spi_mutex;
+#endif
+
+#ifndef SPCR0
+	#define SPCR0 SPCR
+	#define SPE0 SPE
+	#define MSTR0 MSTR
+	#define SPSR0 SPSR
+	#define SPDR0 SPDR
+	#define SPIF0 SPIF
+#endif
+
+/**
+@brief Initialize SPI interface.
+
+Although SPI can have different clock phase and polarity, I have never ran across anything that uses other
+than low polarity and 1st edge phase. Therefore these parameters are implied and not variable. As are 8 bit
+words and MSB first.
+@param[in]	fdiv		Baudrate prescaler, F_CPU dependent
+*/
+void spi_init(uint8_t fdiv)
+{
+	if( SPCR0 & _BV(SPE0) ) return;
+
+	#ifdef SPI_USE_CMT
+	spi_mutex.ac = 0;
+	#endif
+
+	// make SCK, MOSI pins outputs and MISO an input
+	SCK_DDR |= _BV(SCK_BIT);
+	MOSI_DDR |= _BV(MOSI_BIT);
+	MISO_DDR &= ~_BV(MISO_BIT);
+
+	// init SPI, MSB first, SCK low when idle
+	SPCR0 = _BV(SPE0) | _BV(MSTR0) | (fdiv & 3);
+	SPSR0 = (fdiv >> 2) & 1;
+}
+
+/**
+@brief Send and receive byte (NSS not controlled)
+@param[in]	d			Byte to send
+@return byte received
+*/
+uint8_t spi_rw(uint8_t d)
+{
+	#ifdef SPI_USE_CMT
+	cmt_acquire(&spi_mutex);
+	#endif
+
+	SPCR0 |= _BV(MSTR0);
+	SPDR0 = d;
+	while( !(SPSR0 & _BV(SPIF0)) ) {
+		#ifdef SPI_USE_CMT
+		cmt_delay_ticks(0);
+		#endif
+	}
+	d = SPDR0;
+
+	#ifdef SPI_USE_CMT
+	cmt_release(&spi_mutex);
+	#endif
+
+	return d;
+}
+
+// ------------------------------------------------------------------
+// INTERRUPTS
+// ------------------------------------------------------------------
+
+ISR(SPI_STC_vect)
+{
+//
+}

lib/matejx_avr_lib/spi.h

@@ -0,0 +1,13 @@
+#ifndef MAT_SPI_H
+#define MAT_SPI_H
+
+#include <inttypes.h>
+#include <avr/io.h>
+
+// init SPI
+void spi_init(uint8_t fdiv);
+
+// send a byte over SPI
+uint8_t spi_rw(uint8_t d);
+
+#endif

src/cli_microrl.c

@@ -1,3 +1,21 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <avr/pgmspace.h>
@@ -6,6 +24,9 @@
 #include "hmi_msg.h"
 #include "print_helper.h"
 #include "cli_microrl.h"
+#include "../lib/matejx_avr_lib/mfrc522.h"
+#include "rfid.h"
+
 
 typedef struct cli_cmd {
     PGM_P cmd;
@@ -19,7 +40,11 @@ const cli_cmd_t cli_cmds[] = {
     {help_cmd, help_help, cli_print_help, 0},
     {ver_cmd, ver_help, cli_print_ver, 0},
     {ascii_cmd, ascii_help, cli_print_ascii_tbls, 0},
-    {month_cmd, month_help, cli_handle_month, 1}
+    {month_cmd, month_help, cli_handle_month, 1},
+    {read_cmd, read_help, cli_rfid_read, 0},
+    {add_cmd, add_help, cli_rfid_add, 1},
+    {remove_cmd, remove_help, cli_rfid_remove, 1},
+    {list_cmd, list_help, cli_rfid_list, 0}
 };
 
 
@@ -42,7 +67,6 @@ char cli_get_char(void)
 void cli_print_help(const char *const *argv)
 {
     (void) argv;
-    putc('\n', stdout);
     printf_P(PSTR(CLI_HELP_MSG "\n"));
 
     for (uint8_t i = 0; i < NUM_ELEMS(cli_cmds); i++) {
@@ -68,7 +92,6 @@ void print_version(FILE *stream)
 void cli_print_ver(const char *const *argv)
 {
     (void) argv;
-    putc('\n', stdout);
     print_version(stdout);
 }
 
@@ -76,7 +99,6 @@ void cli_print_ver(const char *const *argv)
 void cli_print_ascii_tbls(const char *const *argv)
 {
     (void) argv;
-    putc('\n', stdout);
     // ASCII table print
     print_ascii_tbl(stdout);
     unsigned char ascii[128];
@@ -89,7 +111,6 @@ void cli_print_ascii_tbls(const char *const *argv)
 
 void cli_handle_month(const char *const *argv)
 {
-    putc('\n', stdout);
     lcd_goto(0x40); // Got to the beginning of the next line
     char spaces_to_print = 16;
     for (int i = 0; i < 6; i++) {
@@ -111,16 +132,69 @@ void cli_handle_month(const char *const *argv)
 }
 
 
+void cli_rfid_read(const char *const *argv)
+{
+    (void) argv;
+    Uid uid;
+    Uid *uid_ptr = &uid;
+    if (PICC_IsNewCardPresent()) {
+        printf(CARD_SELECTED_MSG "\n");
+        PICC_ReadCardSerial(uid_ptr);
+        printf_P(PSTR(UID_SIZE_MSG "\n"), uid.size);
+        printf_P(PSTR(UID_SAK_MSG"\n"), uid.sak);
+        printf_P(PSTR(CARD_UID_MSG));
+        for (byte i = 0; i < uid.size; i++) {
+            printf("%02X", uid.uidByte[i]);
+        }
+        putc('\n', stdout);
+    } else {
+        printf_P((PSTR(CARD_NOT_SELECTED)));
+    }
+}
+
+
+void cli_rfid_add(const char *const *argv)
+{
+    (void) argv;
+    Uid uid;
+    card_t card;
+    if (PICC_IsNewCardPresent()) {
+        PICC_ReadCardSerial(&uid);
+        card.uid_size = uid.size;
+        memcpy(&card.uid, &uid.uidByte, uid.size);
+        char *user = malloc(strlen(argv[1]) + 1);
+        strcpy(user, argv[1]);
+        card.user = user;
+        rfid_add_card(&card);
+        free(user); // card user has ben copied to the linked list
+    } else {
+        printf_P(PSTR(UNABLE_TO_DETECT_CARD_MSG "\n"));
+    }
+}
+
+
+void cli_rfid_remove(const char *const *argv)
+{
+    (void) argv;
+    rfid_remove_card_by_user(argv[1]);
+}
+
+
+void cli_rfid_list(const char *const *argv)
+{
+    (void) argv;
+    rfid_list_cards();
+}
+
+
 void cli_print_cmd_error(void)
 {
-    putc('\n', stdout);
     printf_P(PSTR(CLI_NO_CMD "\n"));
 }
 
 
 void cli_print_cmd_arg_error(void)
 {
-    putc('\n', stdout);
     printf_P(PSTR(CLI_ARGS_MSG "\n"));
 }
 
@@ -129,6 +203,7 @@ int cli_execute(int argc, const char *const *argv)
 {
     for (uint8_t i = 0; i < NUM_ELEMS(cli_cmds); i++) {
         if (!strcmp_P(argv[0], cli_cmds[i].cmd)) {
+            putc('\n', stdout);
             // Test do we have correct arguments to run command
             // Function arguments count shall be defined in struct
             if ((argc - 1) != cli_cmds[i].func_argc) {
@@ -142,7 +217,7 @@ int cli_execute(int argc, const char *const *argv)
             return 0;
         }
     }
-
+    putc('\n', stdout);
     cli_print_cmd_error();
     return 0;
 }

src/cli_microrl.h

@@ -1,9 +1,27 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
 #ifndef _CLI_MICRORL_H_
 #define _CLI_MICRORL_H_
 
 #define NUM_ELEMS(x)        (sizeof(x) / sizeof((x)[0]))
 #define UART_STATUS_MASK    0x00FF
 
+
 void cli_print(const char * str);
 char cli_get_char(void);
 void cli_print_help(const char *const *argv);
@@ -11,6 +29,10 @@ void print_version(FILE *stream);
 void cli_print_ver(const char *const *argv);
 void cli_print_ascii_tbls(const char *const *argv);
 void cli_handle_month(const char *const *argv);
+void cli_rfid_read(const char *const *argv);
+void cli_rfid_add(const char *const *argv);
+void cli_rfid_remove(const char *const *argv);
+void cli_rfid_list(const char *const *argv);
 void cli_print_cmd_error(void);
 void cli_print_cmd_arg_error(void);
 int cli_execute(int argc, const char *const *argv);

src/hmi_msg.c

@@ -1,6 +1,24 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
 #include <avr/pgmspace.h>
 #include "hmi_msg.h"
 
+
 static const char m1[] PROGMEM = "January";
 static const char m2[] PROGMEM = "February";
 static const char m3[] PROGMEM = "March";
@@ -18,3 +36,12 @@ const char ascii_cmd[] PROGMEM = ASCII_CMD;
 const char ascii_help[] PROGMEM = ASCII_HELP;
 const char month_cmd[] PROGMEM = MONTH_CMD;
 const char month_help[] PROGMEM = MONTH_HELP;
+const char read_cmd[] PROGMEM = READ_CMD;
+const char read_help[] PROGMEM = READ_HELP;
+const char add_cmd[] PROGMEM = ADD_CMD;
+const char add_help[] PROGMEM = ADD_HELP;
+const char remove_cmd[] PROGMEM = REMOVE_CMD;
+const char remove_help[] PROGMEM = REMOVE_HELP;
+const char list_cmd[] PROGMEM = LIST_CMD;
+const char list_help[] PROGMEM = LIST_HELP;
+const char access_denied_msg[] PROGMEM = ACCESS_DENIED_MSG;

src/hmi_msg.h

@@ -1,24 +1,73 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
 #ifndef _HMI_MSG_H_
 #define _HMI_MSG_H_
 
+
 #define PROG_VERSION "Version: %S built on: %S %S"
 #define LIBC_VERSION "avr-libc version: %S avr-gcc version: %S"
 #define STUD_NAME "Arti Zirk"
 #define GET_MONTH_MSG "Enter Month name first letter >"
 #define UPTIME_MSG "Uptime: %lu s"
 
-#define HELP_CMD "help"
-#define HELP_HELP "Get help"
-#define VER_CMD "version"
-#define VER_HELP "Print FW version"
-#define ASCII_CMD "ascii"
-#define ASCII_HELP "print ASCII tables"
-#define MONTH_CMD "month"
-#define MONTH_HELP "Find matching month from lookup list. Usage: month <string>"
 #define CLI_HELP_MSG "Implemented commands:"
 #define CLI_NO_CMD "Command not implemented.\n Use <help> to get help."
 #define CLI_ARGS_MSG "To few or to many arguments for this command\nUse <help>"
 
+#define HELP_CMD "help"
+#define HELP_HELP "Get help"
+
+#define VER_CMD "version"
+#define VER_HELP "Print FW version"
+
+#define ASCII_CMD "ascii"
+#define ASCII_HELP "print ASCII tables"
+
+#define MONTH_CMD "month"
+#define MONTH_HELP "Find matching month from lookup list. Usage: month <string>"
+
+#define READ_CMD "read"
+#define READ_HELP "Read and print out card info that is currently in proximity of the reader"
+
+#define ADD_CMD "add"
+#define ADD_HELP "Add a new card to the system. Usage: add <username>"
+
+#define REMOVE_CMD "remove"
+#define REMOVE_HELP "Remove a card from the system. Usage: remove <username>"
+
+#define LIST_CMD "list"
+#define LIST_HELP "List all added cards"
+
+#define ACCESS_DENIED_MSG "Access denied!"
+#define NOT_ADDING_CARD_MSG1 "Found card \""
+#define NOT_ADDING_CARD_MSG2 "\", not adding it again."
+#define OUT_OF_MEMORY_MSG "Out of memory. Please remove cards."
+#define NO_CARDS_ADDED_MSG "No cards added"
+#define CARD_NOT_FOUND_MSG "Card not found"
+#define LINKED_LIST_ERROR_MSG "Invalid situation when removing card"
+#define UNABLE_TO_DETECT_CARD_MSG "Unable to detect card."
+#define CARD_SELECTED_MSG "Card selected!"
+#define UID_SIZE_MSG "UID size: 0x%02X"
+#define UID_SAK_MSG "UID sak: 0x%02X"
+#define CARD_UID_MSG "Card UID: "
+#define CARD_NOT_SELECTED "Unable to select card.\n"
+
+
 extern PGM_P const months[];
 
 extern const char help_cmd[];
@@ -29,5 +78,15 @@ extern const char ascii_cmd[];
 extern const char ascii_help[];
 extern const char month_cmd[];
 extern const char month_help[];
+extern const char read_cmd[];
+extern const char read_help[];
+extern const char add_cmd[];
+extern const char add_help[];
+extern const char remove_cmd[];
+extern const char remove_help[];
+extern const char list_cmd[];
+extern const char list_help[];
+extern const char access_denied_msg[];
+
 
 #endif /* _HMI_MSG_H_ */

src/main.c

@@ -1,6 +1,23 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
 #include <stdio.h>
 #include <string.h>
-#include <time.h>
+#include <util/atomic.h>
 #include <avr/io.h>
 #include <avr/interrupt.h>
 #include <avr/pgmspace.h>
@@ -12,19 +29,29 @@
 #include "../lib/hd44780_111/hd44780.h"
 #include "../lib/helius_microrl/microrl.h"
 #include "cli_microrl.h"
+#include "../lib/matejx_avr_lib/mfrc522.h"
+#include "rfid.h"
 
 
+// uart0 and uart3 will run at this speed
 #define BAUDRATE 9600
 
 // For configuring arduino mega pin 25
-#define LED_INIT DDRA |= _BV(DDA3);
+#define LED_INIT DDRA |= _BV(DDA3)
+#define DOOR_INIT DDRA |= _BV(DDA1)
 #define LED_TOGGLE PORTA ^= _BV(PORTA3)
+#define DOOR_OPEN PORTA |= _BV(PORTA1)
+#define DOOR_CLOSE PORTA &= ~_BV(PORTA1)
 #define UART_STATUS_MASK    0x00FF
 
+// Current system time
+volatile uint32_t system_time;
+
 // Create microrl object and pointer on it
 static microrl_t rl;
 static microrl_t *prl = &rl;
 
+
 static inline void init_system_clock(void)
 {
     TCCR5A = 0; // Clear control register A
@@ -35,12 +62,32 @@ static inline void init_system_clock(void)
 }
 
 
+static inline uint32_t time(void)
+{
+    uint32_t cur_time;
+    ATOMIC_BLOCK(ATOMIC_FORCEON) {
+        cur_time = system_time;
+    }
+    return cur_time;
+}
+
+
+static inline void init_rfid_reader(void)
+{
+    MFRC522_init();
+    PCD_Init();
+}
+
+
 static inline void init_hw (void)
 {
     // IO init
-    /// Set arduino pin 25 as output
+    // Set arduino pin 25 as output
     LED_INIT;
 
+    // Set Arduino pin 23 as output
+    DOOR_INIT;
+
     // System clock
     init_system_clock();
 
@@ -54,10 +101,14 @@ static inline void init_hw (void)
     lcd_init();
     lcd_clrscr();
 
+    // Init RFID-RC522
+    init_rfid_reader();
+
     // Enable interupts
     sei();
 }
 
+
 static inline void start_ui (void)
 {
     print_version(stderr);
@@ -68,6 +119,7 @@ static inline void start_ui (void)
     lcd_puts_P(PSTR(STUD_NAME));
 }
 
+
 static inline void start_cli(void)
 {
     // Call init with ptr to microrl instance and print callback
@@ -76,10 +128,11 @@ static inline void start_cli(void)
     microrl_set_execute_callback (prl, cli_execute);
 }
 
+
 static inline void heartbeat (void)
 {
-    static time_t time_prev;
+    static uint32_t time_prev;
-    time_t time_cur = time(NULL);
+    uint32_t time_cur = time();
     if (time_cur <= time_prev) {
         return;
     }
@@ -89,6 +142,54 @@ static inline void heartbeat (void)
 }
 
 
+static inline void handle_door()
+{
+    Uid uid;
+    card_t card;
+    uint32_t time_cur = time();
+    static uint32_t message_start;
+    static uint32_t door_open_start;
+    if (PICC_IsNewCardPresent()) {
+        PICC_ReadCardSerial(&uid);
+        card.uid_size = uid.size;
+        memcpy(&card.uid, &uid.uidByte, uid.size);
+        card.user = NULL;
+        card_t *found_card = rfid_find_card(&card);
+        if (found_card) {
+            lcd_goto(0x40);
+            lcd_puts(found_card->user);
+            for (int8_t i = 16 - strlen(found_card->user); i > -1; i--) {
+                lcd_putc(' ');
+            }
+            DOOR_OPEN;
+        } else {
+            DOOR_CLOSE;
+            lcd_goto(0x40);
+            lcd_puts_P(access_denied_msg);
+            for (int8_t i = 16 - strlen_P(access_denied_msg); i > -1; i--) {
+                lcd_putc(' ');
+            }
+        }
+        door_open_start = time_cur;
+        message_start = time_cur;
+    }
+
+    if ((message_start + 5) < time_cur) {
+        // clean the screen once again in 10 secconds so that cli command
+        // `month` could show found months for some time
+        message_start = time_cur + 5;
+        lcd_goto(0x40);
+        for (int8_t i = 16; i > -1; i--) {
+            lcd_putc(' ');
+        }
+    }
+
+    if ((door_open_start + 2) < time_cur) {
+        DOOR_CLOSE;
+    }
+}
+
+
 int main (void)
 {
     init_hw();
@@ -99,6 +200,7 @@ int main (void)
         heartbeat();
         // CLI commands are handled in cli_execute()
         microrl_insert_char (prl, cli_get_char());
+        handle_door();
     }
 }
 
@@ -106,5 +208,5 @@ int main (void)
 // System clock
 ISR(TIMER5_COMPA_vect)
 {
-    system_tick();
+    system_time++;
 }

src/print_helper.c

@@ -1,7 +1,25 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
 #include <stdio.h>
 #include <avr/pgmspace.h>
 #include "print_helper.h"
 
+
 int print_ascii_tbl (FILE *stream)
 {
     for (char c = ' '; c <= '~'; c++) {

src/print_helper.h

@@ -1,3 +1,20 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
 #ifndef _PRINT_HELPER_H_
 #define _PRINT_HELPER_H_
 

src/rfid.c

@@ -0,0 +1,165 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <avr/pgmspace.h>
+#include "rfid.h"
+#include "hmi_msg.h"
+
+
+card_t *head = NULL;
+
+
+void rfid_print_card(const card_t *card)
+{
+    for (uint8_t i = 0; i < card->uid_size; i++) {
+        printf("%02X", card->uid[i]);
+    }
+    printf(": %s", card->user);
+}
+
+
+card_t* rfid_find_card(const card_t *card)
+{
+    if (head != NULL) {
+        card_t *current;
+        current = head;
+        while (current != NULL) {
+            if (((current->uid_size == card->uid_size) &&
+                    !memcmp(current->uid, card->uid, current->uid_size)) ||
+                    ((card->user != NULL) && !strcmp(current->user, card->user))) {
+
+                return current;
+            }
+            current = current->next;
+        }
+    }
+    return NULL;
+}
+
+
+void rfid_add_card(const card_t *card)
+{
+    card_t *found_card = rfid_find_card(card);
+    if (found_card) {
+        printf_P(PSTR(NOT_ADDING_CARD_MSG1));
+        rfid_print_card(found_card);
+        printf_P(PSTR(NOT_ADDING_CARD_MSG2 "\n"));
+        return;
+    }
+
+    // Card doesn't exist, add it
+    card_t *new_card;
+    char *new_card_user;
+    new_card = malloc(sizeof(card_t));
+    new_card_user = malloc(strlen(card->user) + 1);
+    if (!new_card || !new_card_user) {
+        printf_P(PSTR(OUT_OF_MEMORY_MSG "\n"));
+        free(new_card_user);
+        free(new_card);
+        return;
+    }
+
+    // Copy card data
+    new_card->uid_size = card->uid_size;
+    memcpy(new_card->uid, card->uid, card->uid_size);
+    strcpy(new_card_user, card->user);
+    new_card->user = new_card_user;
+    new_card->next = NULL;
+
+    // Update card list
+    if (head == NULL) {
+        head = new_card;
+    } else {
+        card_t *current;
+        current = head;
+        while (current->next != NULL) {
+            current = current->next;
+        }
+        current->next = new_card;
+    }
+    return;
+}
+
+
+void rfid_list_cards(void)
+{
+    if (head == NULL) {
+        printf_P(PSTR(NO_CARDS_ADDED_MSG "\n"));
+    } else {
+        card_t *current;
+        current = head;
+        while (current->next != NULL) {
+            rfid_print_card(current);
+            putc('\n', stdout);
+            current = current->next;
+        }
+        rfid_print_card(current);
+        putc('\n', stdout);
+    }
+}
+
+
+void rfid_remove_card_by_user(const char *user)
+{
+    card_t *curr;
+    card_t *prev;
+    curr = head;
+    prev = NULL;
+    if (head == NULL) {
+        printf_P(PSTR(NO_CARDS_ADDED_MSG "\n"));
+        return;
+    } else {
+        while (curr->next != NULL) {
+            if (strcmp(curr->user, user) == 0) {
+                break;
+            }
+            prev = curr;
+            curr = curr->next;
+        }
+    }
+    if (strcmp(curr->user, user) == 0) {
+        if (prev == NULL && curr->next == NULL) {
+            // this is the single card in the list
+            free(curr->user);
+            free(curr);
+            head = NULL;
+        } else if (prev == NULL && curr->next != NULL) {
+            // this is the first card in the list, with more after it
+            head = curr->next;
+            free(curr->user);
+            free(curr);
+        } else if (prev != NULL && curr->next != NULL) {
+            // this card is somewhere in the middle of the list
+            prev->next = curr->next;
+            free(curr->user);
+            free(curr);
+        } else if (prev != NULL && curr->next == NULL) {
+            // this is the last card in the list
+            prev->next = NULL;
+            free(curr->user);
+            free(curr);
+        } else {
+            printf_P(PSTR(LINKED_LIST_ERROR_MSG "\n"));
+        }
+    } else {
+        printf_P(PSTR(CARD_NOT_FOUND_MSG));
+    }
+}

src/rfid.h

@@ -0,0 +1,34 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _RFID_H_
+#define _RFID_H_
+
+typedef struct card {
+    uint8_t uid_size;
+    uint8_t uid[10];
+    char *user;
+    struct card *next;
+} card_t;
+
+extern card_t *head;
+extern card_t* rfid_find_card(const card_t *card);
+extern void rfid_add_card(const card_t *card);
+extern void rfid_list_cards(void);
+extern void rfid_remove_card_by_user(const char *user);
+
+#endif /* _RFID_H_ */

src/uart_wrap.c

@@ -1,9 +1,28 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
 #include <avr/io.h>
 #include <stdio.h>
 #include "../lib/andygock_avr-uart/uart.h"
 
+
 #define UART_STATUS_MASK    0x00FF
 
+
 int uart0_putc_wrap(char c, FILE *stream)
 {
     (void) stream;
@@ -16,6 +35,7 @@ int uart0_putc_wrap(char c, FILE *stream)
     return 0;
 }
 
+
 int uart0_getc_wrap(FILE *stream)
 {
     (void) stream;
@@ -26,6 +46,7 @@ int uart0_getc_wrap(FILE *stream)
     return uart0_getc() & UART_STATUS_MASK;
 }
 
+
 int uart3_putc_wrap(char c, FILE *stream)
 {
     (void) stream;

src/uart_wrap.h

@@ -1,3 +1,20 @@
+/*   Copyright (C) 2016 Arti Zirk <arti.zirk@gmail.com>
+ *
+ *   This file is part of I237 Door Access program.
+ *
+ *   I237 Door Access is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   I237 Door Access is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with I237 Door Access.  If not, see <http://www.gnu.org/licenses/>.
+ */
 #ifndef _UART_WRAP_H_
 #define _UART_WRAP_H_