mirror of
git://projects.qi-hardware.com/antorcha.git
synced 2024-11-29 09:13:10 +02:00
99 lines
2.1 KiB
C
99 lines
2.1 KiB
C
/*
|
|
* fw/led.c - LED control
|
|
*
|
|
* Written 2012 by Werner Almesberger
|
|
* Copyright 2012 Werner Almesberger
|
|
*
|
|
* 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 2 of the License, or
|
|
* (at your option) any later version.
|
|
*/
|
|
|
|
|
|
#include <stdint.h>
|
|
|
|
#include <avr/io.h>
|
|
#include <avr/interrupt.h>
|
|
#include <avr/pgmspace.h>
|
|
#define F_CPU 8000000UL
|
|
#include <util/delay.h>
|
|
|
|
#include "io.h"
|
|
#include "led.h"
|
|
|
|
|
|
void led_show(const uint8_t p[LED_BYTES])
|
|
{
|
|
uint8_t i;
|
|
|
|
for (i = 0; i != LED_BYTES; i++) {
|
|
while (!(UCSR0A & (1 << UDRE0)));
|
|
UDR0 = p[i];
|
|
}
|
|
|
|
/*
|
|
* There doesn't seem to be any reliable way to synchronize with the
|
|
* end of the shift operation register that wouldn't cli/sei. Note
|
|
* that, since the receiver is disabled, we can't use the RX side for
|
|
* this purpose (as it is done in the atusb firmware).
|
|
*
|
|
* So instead we just wait for the worst-case delay, being one byte
|
|
* in the shift register and another byte in the transmit buffer,
|
|
* giving a total of 16 bits.
|
|
*
|
|
* This is a bit too pessimistic and produces a slight extra delay of
|
|
* about 1.8 us. (The whole pattern transmission takes 16 us.)
|
|
* See also ../doc/lclk-1123.png
|
|
*/
|
|
|
|
_delay_us(4); /* 16 bits at 4 MHz */
|
|
SET(LED_LCLK);
|
|
CLR(LED_LCLK);
|
|
}
|
|
|
|
|
|
void led_show_pgm(const prog_uint8_t p[LED_BYTES])
|
|
{
|
|
uint8_t i;
|
|
|
|
for (i = 0; i != LED_BYTES; i++) {
|
|
while (!(UCSR0A & (1 << UDRE0)));
|
|
UDR0 = pgm_read_byte(p+i);
|
|
}
|
|
|
|
_delay_us(4); /* 16 bits at 4 MHz */
|
|
SET(LED_LCLK);
|
|
CLR(LED_LCLK);
|
|
}
|
|
|
|
|
|
void led_off(void)
|
|
{
|
|
static uint8_t zero[LED_BYTES] PROGMEM = { 0, };
|
|
|
|
led_show_pgm(zero);
|
|
}
|
|
|
|
|
|
void led_init(void)
|
|
{
|
|
CLR(LED_SCLK);
|
|
OUT(LED_SCLK);
|
|
CLR(LED_LCLK);
|
|
OUT(LED_LCLK);
|
|
|
|
UBRR0 = 0; /* maximum data rate */
|
|
UCSR0C =
|
|
1 << UMSEL01 | /* Master SPI */
|
|
1 << UMSEL00 |
|
|
1 << UDORD0 | /* MSB first */
|
|
0 << UCPHA0 | /* SPI Mode 0 */
|
|
0 << UCPOL0;
|
|
UCSR0B =
|
|
1 << TXEN0; /* enable transmitter */
|
|
UBRR0 = 0; /* the manual sez we need this */
|
|
|
|
led_off();
|
|
}
|