1 files changed, 171 insertions, 0 deletions
diff --git a/src/common/GPIO/usart.c b/src/common/GPIO/usart.c
new file mode 100644
index 0000000..8bcd80a
--- /dev/null
+++ b/src/common/GPIO/usart.c
@@ -0,0 +1,171 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Matthias P. Braendli, Maximilien Cuony
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+*/
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <inttypes.h>
+#include "Core/common.h"
+#include "GPIO/usart.h"
+#include "GPIO/analog.h"
+#include "FreeRTOS.h"
+#include "task.h"
+#include "queue.h"
+
+// The ISR writes into this buffer
+static char nmea_sentence[MAX_NMEA_SENTENCE_LEN];
+static int  nmea_sentence_last_written = 0;
+
+
+// Once a completed NMEA sentence is received in the ISR,
+// it is appended to this queue
+static QueueHandle_t usart_nmea_queue;
+
+void usart_gps_init() {
+    usart_nmea_queue = xQueueCreate(15, MAX_NMEA_SENTENCE_LEN);
+    if (usart_nmea_queue == 0) {
+        while(1); /* fatal error */
+    }
+
+    usart_gps_specific_init();
+
+}
+
+void usart_gps_puts(const char* str) {
+    vTaskSuspendAll();
+    usart_puts(USART3, str);
+    xTaskResumeAll();
+}
+
+#define MAX_MSG_LEN 80
+static char usart_debug_message[MAX_MSG_LEN];
+
+void usart_debug_timestamp() {
+    // Don't call printf here, to reduce stack usage
+    uint64_t now = timestamp_now();
+    if (now == 0) {
+        usart_puts(USART2, "[0] ");
+    }
+    else {
+        char ts_str[64];
+        int i = 63;
+
+        ts_str[i--] = '\0';
+        ts_str[i--] = ' ';
+        ts_str[i--] = ']';
+
+        while (now > 0 && i >= 0) {
+            ts_str[i--] = '0' + (now % 10);
+            now /= 10;
+        }
+        ts_str[i] = '[';
+
+        usart_puts(USART2, &ts_str[i]);
+    }
+}
+
+void usart_debug(const char *format, ...) {
+    va_list list;
+    va_start(list, format);
+    vsnprintf(usart_debug_message, MAX_MSG_LEN-1, format, list);
+
+    vTaskSuspendAll();
+    usart_debug_timestamp();
+    usart_puts(USART2, usart_debug_message);
+    xTaskResumeAll();
+
+    va_end(list);
+}
+
+void usart_debug_puts(const char* str) {
+#ifdef SIMULATOR
+    fprintf(stderr, "DEBUG: %s", str);
+#endif
+    vTaskSuspendAll();
+    usart_debug_timestamp();
+    usart_puts(USART2, str);
+    xTaskResumeAll();
+}
+
+void usart_debug_puts_header(const char* hdr, const char* str) {
+    vTaskSuspendAll();
+    usart_debug_timestamp();
+    usart_puts(USART2, hdr);
+    usart_puts(USART2, str);
+    usart_puts(USART2, "\r\n");
+    xTaskResumeAll();
+}
+
+int usart_get_nmea_sentence(char* nmea) {
+    return xQueueReceive(usart_nmea_queue, nmea, portMAX_DELAY);
+}
+
+
+static void usart_clear_nmea_buffer(void) {
+    for (int i = 0; i < MAX_NMEA_SENTENCE_LEN; i++) {
+        nmea_sentence[i] = '\0';
+    }
+    nmea_sentence_last_written = 0;
+}
+
+void usart_process_char(char c) {
+// Warning: running in interrupt context
+    usart_debug("Unknown command %c\r\n", c);
+}
+
+void usart_gps_process_char(char c)
+{
+    BaseType_t require_context_switch = pdFALSE;
+
+    if (nmea_sentence_last_written == 0) {
+        if (c == '$') {
+            // Likely new start of sentence
+            nmea_sentence[nmea_sentence_last_written] = c;
+            nmea_sentence_last_written++;
+        }
+    }
+    else if (nmea_sentence_last_written < MAX_NMEA_SENTENCE_LEN) {
+        nmea_sentence[nmea_sentence_last_written] = c;
+        nmea_sentence_last_written++;
+
+        if (c == '\n') {
+            int success = xQueueSendToBackFromISR(
+                    usart_nmea_queue,
+                    nmea_sentence,
+                    &require_context_switch);
+
+            if (success == pdFALSE) {
+                trigger_fault(FAULT_SOURCE_USART);
+            }
+
+            usart_clear_nmea_buffer();
+        }
+    }
+    else {
+        // Buffer overrun without a meaningful NMEA message.
+        usart_clear_nmea_buffer();
+    }
+
+    portYIELD_FROM_ISR(require_context_switch);
+}