Better USB connection detection

encoder.c

@@ -5,6 +5,7 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <string.h>
 #include "encoder.h"
 #include "systick.h"
 
@@ -77,8 +78,8 @@ int encoder_speed() {
 int encoder_current_speed() {
   int dt = ticks_ms(tick - speed_ticks[SPEED_AVG_NUM - 1].tick);
   if (dt > 200) {
-    printf("dt: %d", dt);
-    return 0;
+    memmove(&speed_ticks[0], &speed_ticks[1], SPEED_AVG_NUM * sizeof speed_ticks[0]);
+    speed_ticks[SPEED_AVG_NUM].tick = tick;
   }
   return 1000
     * (speed_ticks[SPEED_AVG_NUM-1].pos - speed_ticks[0].pos)

main.c

@@ -4,6 +4,7 @@
 #include <libopencm3/stm32/rcc.h>
 #include <stddef.h>
 #include <stdio.h>
+#include <string.h>
 
 #include "adc.h"
 #include "buttons.h"
@@ -31,6 +32,8 @@ static void erase_app(void);
 #endif
 
 static void fast_reset(void);
+static void set_watchdog(int w);
+static void set_print_changes(int p);
 
 static void sys_tick_setup() {
   systick_set_reload(rcc_ahb_frequency / SYSTICK_FREQUENCY - 1);
@@ -61,6 +64,19 @@ void erase_app() {
 }
 #endif
 
+int watchdog = 0;
+int print_changes = 0;
+
+void set_watchdog(int w) {
+  watchdog = w;
+  printf("watchdog: %d", watchdog);
+}
+
+void set_print_changes(int p) {
+  print_changes = p;
+  printf("pos reporting: %d", print_changes);
+}
+
 int main(void) {
 #if 0
   rcc_clock_setup_pll(&rcc_hse_25mhz_3v3[RCC_CLOCK_3V3_84MHZ]);
@@ -86,18 +102,20 @@ int main(void) {
 
   uint32_t last_tick = tick;
   int last_pos = 0;
-  int watchdog = 1;
   uint32_t watchdog_counter = 0;
-  int print_changes = 0;
 
-  while (tick < 5000) {
+  while (tick < 5000 && !usb_connected()) {
     usbd_poll(g_usbd_dev);
   }
 
-  if (!usb_got_reset()) {
+  if (!usb_connected()) {
     fast_reset();
   }
 
+  char cmd_buf[64];
+  uint8_t cmd_len = 0;
+  bool cmd = false;
+
   while (1) {
     /* Handle control messages through the comms CDC */
     char buf[64];
@@ -117,7 +135,37 @@ int main(void) {
     }
 
     for (char c; ringbuffer_get(comm_in_buf, (void *)&c, 1);) {
-      switch (c) {
+      if (cmd) {
+        if (c == '\r' || c == '\n') {
+          cmd_buf[cmd_len] = 0;
+
+          if (cmd_buf[0] == 'r' && cmd_len == 2 && (cmd_buf[1] == '0' || cmd_buf[1] == '1')) {
+            set_print_changes(cmd_buf[1] == '1');
+          } else if(cmd_buf[0] == 'w' && cmd_len == 2 && (cmd_buf[1] == '0' || cmd_buf[1] == '1')) {
+            set_watchdog(cmd_buf[1] == '1');
+          } else if (!strcmp(cmd_buf, "reset")) {
+            fast_reset();
+          }
+#if defined(BOOTLOADER)
+          else if (!strcmp(cmd_buf, "flash")) {
+            start_bootloader();
+          } else if (!strcmp(cmd_buf, "erase")) {
+            erase_app();
+          }
+#endif
+          else {
+            printf("unknown command: %s", cmd_buf);
+          }
+          cmd = false;
+        } else if (cmd_len < sizeof cmd_buf - 1) {
+          cmd_buf[cmd_len++] = c;
+        }
+      }
+      else switch (c) {
+        case '>':
+          cmd = true;
+          cmd_len = 0;
+          break;
         case 'B': // Battery
           printf("%lu", (unsigned long)adc_bat_voltage());
           break;
@@ -131,12 +179,10 @@ int main(void) {
           printf("pos: %d %d", encoder_get(), encoder_current_speed());
           break;
         case 'r': // toggle reporting
-          print_changes = !print_changes;
-          printf("pos reporting: %d", print_changes);
+          set_print_changes(!print_changes);
           break;
         case 'W': // toggle watchdog
-          watchdog = !watchdog;
-          printf("watchdog: %d", watchdog);
+          set_watchdog(!watchdog);
           break;
         case 'S': // reStart
           fast_reset();
@@ -164,7 +210,7 @@ int main(void) {
 
     /* Send replies */
     if ((buf_len = ringbuffer_peek(comm_out_buf, &buf[0], sizeof buf))) {
-      if (usb_write_cdcacm(ACM_COMM, (void *)buf, buf_len, 1)) {
+      if (!usb_connected() || usb_write_cdcacm(ACM_COMM, (void *)buf, buf_len, 1)) {
         ringbuffer_skip(comm_out_buf, buf_len);
       }
     }
@@ -172,7 +218,7 @@ int main(void) {
     /* Send any available data to the NFC CDC */
     if (!ringbuffer_empty(uart_to_usb_buf)) {
       unsigned len = ringbuffer_peek(uart_to_usb_buf, &buf[0], sizeof buf);
-      if (usb_write_cdcacm(ACM_NFC, &buf[0], len, 1)) {
+      if (!usb_connected() || usb_write_cdcacm(ACM_NFC, &buf[0], len, 1)) {
         ringbuffer_skip(uart_to_usb_buf, len);
       }
     }

usb.c

@@ -11,6 +11,9 @@
 
 extern ringbuffer *usb_to_uart_buf, *comm_in_buf;
 
+static void usb_reset_callback(void);
+static void usb_suspend_callback(void);
+
 /* Number of serial devices we want to provide. */
 #define NUM_SERIAL 2
 
@@ -40,7 +43,7 @@ static char const *usb_strings[] = {
     [3 + ACM_NFC] = "RFID",
 };
 
-static int got_reset = 0;
+static int connected = 0;
 
 usbd_device *g_usbd_dev;
 
@@ -176,11 +179,15 @@ static void cdcacm_set_config(usbd_device *usbd_dev, uint16_t wValue) {
 }
 
 void usb_reset_callback(void) {
-  got_reset = 1;
+  connected = 1;
 }
 
-bool usb_got_reset(void) {
-  return got_reset;
+void usb_suspend_callback(void) {
+  connected = 0;
+}
+
+bool usb_connected(void) {
+  return connected;
 }
 
 void usb_setup() {
@@ -337,6 +344,7 @@ void usb_reinit() {
                          usbd_control_buffer, sizeof(usbd_control_buffer));
 
   usbd_register_reset_callback(g_usbd_dev, &usb_reset_callback);
+  usbd_register_suspend_callback(g_usbd_dev, &usb_suspend_callback);
   usbd_register_set_config_callback(g_usbd_dev, cdcacm_set_config);
 }
 

usb.h

@@ -8,7 +8,7 @@ extern usbd_device *g_usbd_dev;
 void usb_setup(void);
 void usb_reinit(void);
 int usb_write_cdcacm(uint8_t acm, void *data, size_t len, int tries);
-bool usb_got_reset(void);
+bool usb_connected(void);
 
 #define ACM_NFC 1
 #define ACM_COMM 0