init

src/delay.h

@@ -0,0 +1,143 @@
+/*
+ * This file is part of the HAL project, inline library above libopencm3.
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/** @defgroup DELAY_module DELAY module
+ *
+ * @brief Spin-waiting blocking API
+ *
+ * @ingroup modules
+ *
+ * LGPL License Terms @ref lgpl_license
+ */
+#ifndef HAL_DELAY_H_INCLUDED
+#define HAL_DELAY_H_INCLUDED
+
+#include <libopencm3/cm3/common.h>
+#include <libopencm3/stm32/rcc.h>
+
+/**@{*/
+
+/*****************************************************************************/
+/* API definitions                                                           */
+/*****************************************************************************/
+
+/*****************************************************************************/
+/* API Functions                                                             */
+/*****************************************************************************/
+
+BEGIN_DECLS
+
+/*---------------------------------------------------------------------------*/
+/** @brief Spin-wait delay, spinning specified amount of processor cycles
+ *
+ * @note this function can be used for delays of max 2500000 cycles.
+ * For larger delays, please consider using timers or other waiting techniques.
+ *
+ * @param[in] cycles Cycles count need to spent in spin-wait
+ */
+static void delay_cycles(const int64_t cycles);
+
+/*---------------------------------------------------------------------------*/
+/** @brief Spin-wait delay, spinning specified amount of microseconds
+ *
+ * @note this function can be used for delays max 25 sec @ 168MHz CPU clock, or
+ * max 525 sec @ 8MHz CPU clock! For larger delays, please consider using
+ * timers or other waiting techniques.
+ *
+ * @param[in] us Microseconds needed to spin wait.
+ * @param[in] cpufreq Current CPU frequency in Hz
+ */
+static void delay_us(uint32_t us);
+
+/*---------------------------------------------------------------------------*/
+/** @brief Spin-wait delay, spinning specified amount of microseconds
+ *
+ * @note this function can be used for delays max 25 sec @ 168MHz CPU clock, or
+ * max 525 sec @ 8MHz CPU clock! For larger delays, please consider using
+ * timers or other waiting techniques.
+ *
+ * @param[in] ms Milliseconds needed to spin wait.
+ * @param[in] cpufreq Current CPU frequency in Hz
+ */
+static void delay_ms(uint32_t ms);
+
+END_DECLS
+
+/**@}*/
+
+/*****************************************************************************/
+/* Architecture dependent implementations                                    */
+/*****************************************************************************/
+
+static void _delay_3t(uint32_t cycles) __attribute__((naked));
+
+/* 3 Tcyc per tick, 4Tcyc call/ret, 1Tcyc hidden reg assignment */
+static void _delay_3t(uint32_t cycles)
+{
+    asm __volatile__ (
+    ".syntax unified\n"
+    "1: \n"
+    "	subs %[cyc],#1 \n"	/* 1Tck */
+    "	bne 1b \n"		/* 2Tck */
+    "	bx lr \n"
+    ".syntax divided\n"
+    : /* No output */
+    : [cyc] "r" (cycles)
+    : /* No memory */
+    );
+}
+
+
+static inline __attribute__((always_inline)) void delay_cycles(const int64_t cycles)
+{
+    if (cycles <= 0)
+        return;
+
+    switch (cycles % 3) {
+        default:
+        case 0: break;
+        case 1: asm __volatile__ ("nop"); break;
+        case 2: asm __volatile__ ("nop\nnop"); break;
+    }
+
+    if (cycles > 3)
+        _delay_3t((uint32_t)(cycles / 3));
+    else /* same delay as the function call */
+            asm __volatile__ ("nop\nnop\nnop\nnop\nnop\nnop\n");
+}
+
+
+/* max 25 sec @ 168MHz! */
+/* max 525 sec @ 8MHz! */
+static inline __attribute__((always_inline)) void delay_us(uint32_t us)
+{
+    if (us == 0)
+        return;
+
+    delay_cycles(us * rcc_ahb_frequency / 1000000 - 6);
+}
+
+/* max 25 sec @ 168MHz! */
+/* max 525 sec @ 8MHz! */
+static inline __attribute__((always_inline)) void delay_ms(uint32_t ms)
+{
+    if (ms == 0)
+        return;
+
+    delay_cycles(ms * rcc_ahb_frequency / 1000 - 6);
+}
+
+#endif /* HAL_DELAY_H_INCLUDED */

src/main.c

@@ -0,0 +1,5 @@
+#include <SEGGER_RTT.h>
+
+void main(void) {
+    SEGGER_RTT_printf(0, "Hello World\n");
+}

src/util.c

@@ -0,0 +1,17 @@
+#include <SEGGER_RTT.h>
+#include "util.h"
+
+void hexdump(char *buf, size_t size, uint32_t width) {
+    if (width == 0) {
+        width = 16;
+    }
+    SEGGER_RTT_SetFlagsUpBuffer(0, SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL);
+    for (unsigned int i = 0; i < size; i++) {
+        SEGGER_RTT_printf(0, "%.2x ", buf[i]);
+        if ((i+1) % width == 0) {
+            SEGGER_RTT_printf(0,"\n");
+        }
+    }
+    SEGGER_RTT_printf(0,"\n");
+    SEGGER_RTT_SetFlagsUpBuffer(0, SEGGER_RTT_MODE_DEFAULT);
+}

src/util.h

@@ -0,0 +1,8 @@
+#ifndef DHT_TEST_UTIL_H
+#define DHT_TEST_UTIL_H
+
+#include <stdint.h>
+
+void hexdump(char *buf, size_t size, uint32_t width);
+
+#endif //DHT_TEST_UTIL_H