Interrupt on both edges of the gps timepulse to ensure we hit the hardware watchdog often enough. Also control the external WDI line as an awake/asleep trigger for debugging.

This introduces a uncertainty of ±0.5s on the internal time, but we can ignore that for the moment

firmware/inc/pips.h

@@ -30,7 +30,7 @@
  */
 
 #define PIPS_RATE	1
-#define PIPS_LENGTH_MS	250
+#define PIPS_LENGTH_MS	200
 #define PIPS_FREQUENCY	(1000 / PIPS_LENGTH_MS)
 
 #endif /* PIPS_H */

firmware/inc/watchdog.h

@@ -52,6 +52,7 @@ struct idle_counter {
   uint32_t wait_for_next_telemetry;
 };
 
+void awake_do_watchdog(void);
 void kick_the_watchdog(void);
 void idle(idle_wait_t idle_t);
 void watchdog_init(void);

firmware/src/adc/adc.c

@@ -48,6 +48,7 @@
 #include "system/system.h"
 #include "system/pinmux.h"
 #include "adc/adc.h"
+#include "watchdog.h"
 
 #define Assert assert
 
@@ -531,6 +532,8 @@ enum adc_status_code adc_init(Adc *hw,
 /** Interrupt handler for the ADC module. */
 void ADC_Handler(void)
 {
+  awake_do_watchdog();
+
   /* get interrupt flags and mask out enabled callbacks */
   uint32_t flags = module_inst.hw->INTFLAG.reg;
 

firmware/src/telemetry.c

@@ -41,7 +41,7 @@
 #include "system/port.h"
 #include "tc/tc_driver.h"
 #include "hw_config.h"
-
+#include "watchdog.h"
 
 /**
  * CYCLIC REDUNDANCY CHECK (CRC)
@@ -418,6 +418,8 @@ void timer0_tick_deinit()
  */
 void TC0_Handler(void)
 {
+  awake_do_watchdog();
+
   while (tc_get_status(TC0) & TC_STATUS_CHANNEL_0_MATCH) {
     tc_clear_status(TC0, TC_STATUS_CHANNEL_0_MATCH);
 

firmware/src/timer.c

@@ -31,8 +31,9 @@
 #include "system/events.h"
 #include "system/interrupt.h"
 #include "system/port.h"
+#include "watchdog.h"
 
-uint32_t gps_timepulse_count = 0;
+volatile uint32_t gps_timepulse_count = 0;
 uint32_t timepulse_sequence = 0;
 
 timepulse_callback_t _timer_callback;
@@ -56,15 +57,15 @@ void timepulse_extint_init(void) {
   struct extint_chan_conf config;
   config.gpio_pin = GPS_TIMEPULSE_PIN;
   config.gpio_pin_mux = GPS_TIMEPULSE_PINMUX;
-  config.gpio_pin_pull = EXTINT_PULL_NONE; // ???
-  config.wake_if_sleeping = false; // ???
+  config.gpio_pin_pull = EXTINT_PULL_DOWN;
+  config.wake_if_sleeping = true;
   config.filter_input_signal = false;
-  config.detection_criteria = EXTINT_DETECT_RISING;
+  config.detection_criteria = EXTINT_DETECT_BOTH;
   extint_chan_set_config(GPS_TIMEPULSE_EXTINT, &config);
 
   /* We route this event to event channel 0 */
   events_allocate(0,
-                  EVENTS_EDGE_DETECT_NONE,
+                  EVENTS_EDGE_DETECT_NONE, /* Don't care for async path */
                   EVENTS_PATH_ASYNCHRONOUS,
                   0xC + GPS_TIMEPULSE_EXTINT, /* External Interrupt Number */
                   0);
@@ -83,14 +84,16 @@ void timepulse_set_callback(timepulse_callback_t callback) {
 /**
  * EIC Handler, triggered by the GPS at GPS_TIMEPULSE_FREQ Hz
  */
-void EIC_Handler(void) {
+void EIC_Handler(void)
+{
+  awake_do_watchdog();
 
   if (EIC->INTFLAG.reg & (1 << GPS_TIMEPULSE_EXTINT)) {
     EIC->INTFLAG.reg = (1 << GPS_TIMEPULSE_EXTINT);
 
     gps_timepulse_count++;
     /* Runs at 1Hz */
-    if (gps_timepulse_count >= GPS_TIMEPULSE_FREQ) {
+    if (gps_timepulse_count >= GPS_TIMEPULSE_FREQ * 2) { /* Both */
       gps_timepulse_count = 0;
 
       /* Make the callback if we have one */

firmware/src/watchdog.c

@@ -39,7 +39,7 @@ struct idle_counter idle_count, idle_count_max;
 
 idle_wait_t last_idle_t = IDLE_NONE;
 
-#define kick_external_watchdog()	  port_pin_toggle_output_level(WDT_WDI_PIN)
+#define kick_external_watchdog()	port_pin_toggle_output_level(WDT_WDI_PIN)
 
 /**
  * Increments the specified idle counter
@@ -88,6 +88,18 @@ void clear_idle_counters(void)
   memset(&idle_count, 0, sizeof(struct idle_counter));
 }
 
+/**
+ * To be run when we wake from sleep
+ */
+void awake_do_watchdog(void)
+{
+#ifdef DEBUG_USE_INTWATCHDOG
+  wdt_reset_count();
+#endif
+
+  /* WDI high */
+  port_pin_set_output_level(WDT_WDI_PIN, 1);
+}
 /**
  * Kick
  */
@@ -130,24 +142,18 @@ void idle(idle_wait_t idle_t)
   wdt_reset_count();
 #endif
 
+  /* WDI low */
   port_pin_set_output_level(WDT_WDI_PIN, 0);
 
   /* And sleep */
   system_sleep();
-
-  /* Same again when we wake from sleep */
-#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.
- * 0.8s < t_early_w < 0.128s
+ * coredump to external memory (todo)
+ * 0.6s < t_early_w < 0.96s
  *
  * The external watchdog then hard resets the MCU and GPS to bring the
  * system back up in a clean state.
@@ -168,12 +174,12 @@ void watchdog_init(void)
   system_gclk_gen_set_config(WDT_GCLK,
         		     GCLK_SOURCE_OSCULP32K, /* Source 		*/
         		     false,		/* High When Disabled	*/
-        		     4,			/* Division Factor 1	*/
+        		     3,			/* Division Factor	*/
         		     false,		/* Run in standby	*/
         		     true);		/* Output Pin Enable	*/
   system_gclk_gen_enable(WDT_GCLK);
 
-  /* Set the watchdog timer. On 8kHz gclk  */
+  /* Set the watchdog timer. On ~11kHz gclk  */
   wdt_set_config(false,			/* Lock WDT		*/
                  true,			/* Enable WDT		*/
                  WDT_GCLK,		/* Clock Source		*/

firmware/src/xosc.c

@@ -34,7 +34,7 @@
 #include "tc/tc_driver.h"
 #include "hw_config.h"
 #include "xosc.h"
-
+#include "watchdog.h"
 
 enum measure_state_t {
   MEASURE_WAIT_FOR_FIRST_EVENT,
@@ -235,7 +235,6 @@ void measure_xosc_disable(enum xosc_measurement_t measurement_t) {
   }
 }
 
-
 /**
  * Triggered on timer 2 capture
  */
@@ -243,6 +242,8 @@ void TC2_Handler(void) {
   uint32_t capture_value;
   uint32_t source_freq;
 
+  awake_do_watchdog();
+
   if (tc_get_status(TC2) & TC_STATUS_CHANNEL_0_MATCH) {
     tc_clear_status(TC2, TC_STATUS_CHANNEL_0_MATCH);