Increase the frequency of the internal watchdog gclk so we don't get massive lag when kicking it. Also fix up varous timing issues / speed things up

firmware/inc/hw_config.h

@@ -167,7 +167,11 @@
 
 /**
  * Watchdog Timer
+ *
+ * There is a performance penalty to using the watchdog - you must
+ * wait up to 1/16kHz when kicking to sync with it. Disable when not in use
  */
+#define DEBUG_USE_INTWATCHDOG	1
 #define WDT_GCLK		GCLK_GENERATOR_4
 
 /**

firmware/inc/si_trx.h

@@ -34,7 +34,10 @@ void si_trx_modem_set_deviation(uint32_t deviation);
 void si_trx_on(uint8_t modulation_type, uint32_t frequency,
                uint16_t deviation, uint8_t power);
 void si_trx_off(void);
-void si_trx_switch_channel(int16_t channel);
+
+void si_trx_modem_set_offset(int16_t channel);
+#define si_trx_switch_channel si_trx_modem_set_offset
+
 
 void si_trx_shutdown(void);
 void si_trx_init(void);

firmware/src/si_trx.c

@@ -300,7 +300,7 @@ static void si_trx_modem_tx_filter_coefficients(uint8_t* coeff_array)
  *
  * This is a signed 16-bit value.
  */
-static void si_trx_modem_set_offset(int16_t offset)
+void si_trx_modem_set_offset(int16_t offset)
 {
   /* _si_trx_set_property_16(SI_PROPERTY_GROUP_MODEM, */
   /*                         SI_MODEM_FREQ_OFFSET, */
@@ -489,14 +489,6 @@ void si_trx_off(void)
   _si_trx_sdn_enable();
 }
 
-/**
- * Switches the transmission to the specified channel. Signed 16-bit int
- */
-void si_trx_switch_channel(int16_t channel)
-{
-  si_trx_modem_set_offset(channel);
-}
-
 /**
  * Resets the radio
  */

firmware/src/telemetry.c

@@ -363,6 +363,8 @@ const uint8_t tick_gclk_gen_num = 1;
  */
 void timer0_tick_init(uint32_t count)
 {
+  tc_reset(TC0);
+
   /* Configure Timer 0 */
   bool t0_capture_channel_enables[]    = {false, false};
   uint32_t t0_compare_channel_values[] = {count, 0x0000};
@@ -381,15 +383,8 @@ void timer0_tick_init(uint32_t count)
 	  t0_capture_channel_enables,	/* Capture Channel Enables */
 	  t0_compare_channel_values);	/* Compare Channels Values */
 
-  /* Enable Events */
-  struct tc_events event;
-  memset(&event, 0, sizeof(struct tc_events));
-  event.generate_event_on_compare_channel[0] = true;
-  event.event_action = TC_EVENT_ACTION_RETRIGGER;
-  tc_enable_events(TC0, &event);
-
   /* Enable Interrupt */
-  TC0->COUNT16.INTENSET.reg = TC_INTENSET_MC0;
+  TC0->COUNT32.INTENSET.reg = TC_INTENSET_MC0;
   irq_register_handler(TC0_IRQn, TC0_INT_PRIO); /* Highest Priority */
 
   /* Enable Timer */
@@ -420,7 +415,7 @@ void timer0_tick_deinit()
  */
 void TC0_Handler(void)
 {
-  if (tc_get_status(TC0) & TC_STATUS_CHANNEL_0_MATCH) {
+  while (tc_get_status(TC0) & TC_STATUS_CHANNEL_0_MATCH) {
     tc_clear_status(TC0, TC_STATUS_CHANNEL_0_MATCH);
 
     telemetry_tick();

firmware/src/timer.c

@@ -30,6 +30,7 @@
 #include "system/extint.h"
 #include "system/events.h"
 #include "system/interrupt.h"
+#include "system/port.h"
 
 uint32_t gps_timepulse_count = 0;
 uint32_t timepulse_sequence = 0;
@@ -48,6 +49,10 @@ void timepulse_extint_init(void) {
   extint_enable_events(&events);
 
   /* Configure extinit channel */
+  /**
+   * We trigger on both edges so that we get woken up at 2x the tick
+   * rate. This means we can kick the watchdog often enough.
+   */
   struct extint_chan_conf config;
   config.gpio_pin = GPS_TIMEPULSE_PIN;
   config.gpio_pin_mux = GPS_TIMEPULSE_PINMUX;

firmware/src/watchdog.c

@@ -93,12 +93,6 @@ void clear_idle_counters(void)
  */
 void kick_the_watchdog(void)
 {
-  /* tc_set_count_value(TC1, 0); */
-  /* tc_clear_status(TC1, TC_STATUS_CHANNEL_0_MATCH); */
-
-  wdt_reset_count();
-
-  kick_external_watchdog();
 }
 /**
  * Called in idle loops. Kicks the watchdog
@@ -128,20 +122,28 @@ void idle(idle_wait_t idle_t)
   check_idle_counters();
 
   /* Kick the watchdog */
-  kick_the_watchdog();
+#ifdef DEBUG_USE_INTWATCHDOG
+  wdt_reset_count();
+#endif
+
+  port_pin_set_output_level(WDT_WDI_PIN, 0);
 
   /* And sleep */
   system_sleep();
 
   /* Same again when we wake from sleep */
-  kick_the_watchdog();
+#ifdef DEBUG_USE_INTWATCHDOG
+  wdt_reset_count();
+#endif
+
+  port_pin_set_output_level(WDT_WDI_PIN, 1);
 }
 
 
 /**
  * The internal watchdog is used to bring the processor to a halt and
  * coredump to external memory.
- * 0.4s < t_early_w < 0.64s
+ * 0.8s < t_early_w < 0.128s
  *
  * The external watchdog then hard resets the MCU and GPS to bring the
  * system back up in a clean state.
@@ -157,30 +159,30 @@ void watchdog_init(void)
 		      false);			/* Powersave */
   kick_external_watchdog();                     /* Kick External */
 
+#if DEBUG_USE_INTWATCHDOG
   /* /\* 0.5s early warn. So 2^(15-1) cycles of the 32.768kHz ulposc *\/ */
   system_gclk_gen_set_config(WDT_GCLK,
         		     GCLK_SOURCE_OSCULP32K, /* Source 		*/
         		     false,		/* High When Disabled	*/
-        		     128,		/* Division Factor 2^7  */
+        		     4,			/* Division Factor 1	*/
         		     false,		/* Run in standby	*/
         		     true);		/* Output Pin Enable	*/
   system_gclk_gen_enable(WDT_GCLK);
 
-  /* Set the watchdog timer. On 256Hz gclk  */
+  /* Set the watchdog timer. On 8kHz gclk  */
   wdt_set_config(false,			/* Lock WDT		*/
                  true,			/* Enable WDT		*/
                  WDT_GCLK,		/* Clock Source		*/
                  WDT_PERIOD_16384CLK,	/* Timeout Period	*/
                  WDT_PERIOD_NONE,	/* Window Period	*/
-                 WDT_PERIOD_128CLK);	/* Early Warning Period	*/
+                 WDT_PERIOD_8192CLK);	/* Early Warning Period	*/
 
   WDT->INTENSET.reg |= WDT_INTENSET_EW;
   WDT->INTFLAG.reg |= WDT_INTFLAG_EW;
   irq_register_handler(WDT_IRQn, WDT_INT_PRIO);
 
-  /* Kick Watchdogs */
-  kick_external_watchdog();
   wdt_reset_count();
+#endif
 }