Util Timer no longer uses RTC - works based on estimated time from the hardware timer itself (fix espruino#1749, ref espruino#1444)

gfwilliams · gfwilliams · commit fbdb6c704cdd · 2020-11-03T08:21:08.000Z
diff --git a/ChangeLog b/ChangeLog
@@ -8,6 +8,7 @@
             nRF52: Ensure SPI 1 byte DMA errata workaround isn't applied to non-52832 parts
             nRF52: When outputting assertions, if we have an terminal device (eg LCD) use that
             When load(filename) is used, set global variable __FILE__ to the filename
+            Util Timer no longer uses RTC - works based on estimated time from the hardware timer itself (fix #1749, ref #1444)
  
      2v08 : nRF52: Added option to build in I2C slave support
             Fix Tensorflow aiGesture regression from 2v07 (re-add opcodes) (fix #1936)
diff --git a/src/jstimer.c b/src/jstimer.c
@@ -15,16 +15,24 @@
 #include "jsparse.h"
 #include "jsinteractive.h"
 
+/// Data for our tasks (eg when, what they are, etc)
 UtilTimerTask utilTimerTasks[UTILTIMERTASK_TASKS];
+/// queue beginning (push tasks on here)
 volatile unsigned char utilTimerTasksHead = 0;
+/// queue end (tasks pop off here as they are complete)
 volatile unsigned char utilTimerTasksTail = 0;
 
-
+/// Is the utility timer actually running?
 volatile bool utilTimerOn = false;
+
 unsigned int utilTimerBit;
 bool utilTimerInIRQ = false;
 unsigned int utilTimerData;
 uint16_t utilTimerReload0H, utilTimerReload0L, utilTimerReload1H, utilTimerReload1L;
+/// When did the timer last run? This is used for timekeeping. Should be jshGetSystemTime() cropped to 32 bits
+volatile int utilTimerTime;
+/// When we rescheduled the timer, how far in the future were we meant to get called?
+int utilTimerPeriod;
 
 
 #ifndef SAVE_ON_FLASH
@@ -77,11 +85,19 @@ static inline unsigned char *jstUtilTimerInterruptHandlerByte(UtilTimerTask *tas
 #endif
 
 void jstUtilTimerInterruptHandler() {
+  /* Note: we're using 32 bit times here, even though the real time counter is 64 bit.
+   * It means when we do compares, we do them by first subtracting 'utilTimerTime'
+   * which means that even if the numbers overflow, they will still be correct relative
+   * to each other.
+   */
+  jshPinOutput(31,1);
   if (utilTimerOn) {
     utilTimerInIRQ = true;
-    JsSysTime time = jshGetSystemTime();
+    // Increment estimated timer time
+    // TODO: use SysTick to estimate time in this fn and update utilTimerTime accordingly
+    utilTimerTime += utilTimerPeriod;
     // execute any timers that are due
-    while (utilTimerTasksTail!=utilTimerTasksHead && utilTimerTasks[utilTimerTasksTail].time <= time) {
+    while (utilTimerTasksTail!=utilTimerTasksHead && (utilTimerTasks[utilTimerTasksTail].time - utilTimerTime)<=0) {
       UtilTimerTask *task = &utilTimerTasks[utilTimerTasksTail];
       void (*executeFn)(JsSysTime time, void* userdata) = 0;
       void *executeData = 0;
@@ -150,15 +166,14 @@ void jstUtilTimerInterruptHandler() {
       }
       // If we need to repeat
       if (task->repeatInterval) {
-        // update time (we know time > task->time) - what if we're being asked to do too fast? skip one (or 500 :)
-        unsigned int t = ((unsigned int)(time+task->repeatInterval - task->time)) / task->repeatInterval;
-        if (t<1) t=1;
-        task->time = task->time + (JsSysTime)task->repeatInterval*t;
+        // update time (we know time > task->time)
+        task->time += task->repeatInterval;
+
         // do an in-place bubble sort to ensure that times are still in the right order
         unsigned char ta = utilTimerTasksTail;
         unsigned char tb = (ta+1) & (UTILTIMERTASK_TASKS-1);
         while (tb != utilTimerTasksHead) {
-          if (utilTimerTasks[ta].time > utilTimerTasks[tb].time) {
+          if ((utilTimerTasks[ta].time-utilTimerTime) > (utilTimerTasks[tb].time-utilTimerTime)) {
             UtilTimerTask task = utilTimerTasks[ta];
             utilTimerTasks[ta] = utilTimerTasks[tb];
             utilTimerTasks[tb] = task;
@@ -172,12 +187,14 @@ void jstUtilTimerInterruptHandler() {
       }
 
       // execute the function if we had one (we do this now, because if we did it earlier we'd have to cope with everything changing)
-      if (executeFn) executeFn(time, executeData);
+      if (executeFn) executeFn(jshGetSystemTime(), executeData);
     }
 
     // re-schedule the timer if there is something left to do
     if (utilTimerTasksTail != utilTimerTasksHead) {
-      jshUtilTimerReschedule(utilTimerTasks[utilTimerTasksTail].time - time);
+      utilTimerPeriod = utilTimerTasks[utilTimerTasksTail].time - utilTimerTime;
+      if (utilTimerPeriod<0) utilTimerPeriod=0;
+      jshUtilTimerReschedule(utilTimerPeriod);
     } else {
       utilTimerOn = false;
       jshUtilTimerDisable();
@@ -187,6 +204,7 @@ void jstUtilTimerInterruptHandler() {
     // Nothing left to do - disable the timer
     jshUtilTimerDisable();
   }
+  jshPinOutput(31,0);
 }
 
 /// Return true if the utility timer is running
@@ -207,7 +225,10 @@ static bool utilTimerIsFull() {
 /* Restart the utility timer with the right period. This should not normally
 need to be called by anything outside jstimer.c */
 void  jstRestartUtilTimer() {
-  jshUtilTimerStart(utilTimerTasks[utilTimerTasksTail].time - jshGetSystemTime());
+  utilTimerTime = (int)jshGetSystemTime();
+  utilTimerPeriod = utilTimerTasks[utilTimerTasksTail].time - utilTimerTime;
+  if (utilTimerPeriod<0) utilTimerPeriod=0;
+  jshUtilTimerStart(utilTimerPeriod);
 }
 
 // Queue a task up to be executed when a timer fires... return false on failure
@@ -347,7 +368,7 @@ bool jstGetLastBufferTimerTask(JsVar *var, UtilTimerTask *task) {
 bool jstPinOutputAtTime(JsSysTime time, Pin *pins, int pinCount, uint8_t value) {
   assert(pinCount<=UTILTIMERTASK_PIN_COUNT);
   UtilTimerTask task;
-  task.time = time;
+  task.time = (int)time;
   task.repeatInterval = 0;
   task.type = UET_SET;
   int i;
@@ -415,12 +436,11 @@ bool jstPinPWM(JsVarFloat freq, JsVarFloat dutyCycle, Pin pin) {
     while (utilTimerRemoveTask(jstPinTaskChecker, (void*)&pin));
   }
   JsSysTime time = jshGetSystemTime();
-
   UtilTimerTask taskon, taskoff;
   taskon.data.set.value = 1;
   taskoff.data.set.value = 0;
-  taskon.time = time;
-  taskoff.time = time + pulseLength;
+  taskon.time = (int)time;
+  taskoff.time = (int)(time + pulseLength);
   taskon.repeatInterval = (unsigned int)period;
   taskoff.repeatInterval = (unsigned int)period;
   taskon.type = UET_SET;
@@ -442,7 +462,7 @@ bool jstPinPWM(JsVarFloat freq, JsVarFloat dutyCycle, Pin pin) {
 /// Execute the given function repeatedly after the given time period
 bool jstExecuteFn(UtilTimerTaskExecFn fn, void *userdata, JsSysTime startTime, uint32_t period) {
   UtilTimerTask task;
-  task.time = startTime;
+  task.time = (int)startTime;
   task.repeatInterval = period;
   task.type = UET_EXECUTE;
   task.data.execute.fn = fn;
@@ -463,12 +483,12 @@ bool jstStopExecuteFn(UtilTimerTaskExecFn fn, void *userdata) {
 /// Set the utility timer so we're woken up in whatever time period
 bool jstSetWakeUp(JsSysTime period) {
   UtilTimerTask task;
-  task.time = jshGetSystemTime() + period;
+  task.time = (int)(jshGetSystemTime() + period);
   task.repeatInterval = 0;
   task.type = UET_WAKEUP;
 
   bool hasTimer = false;
-  JsSysTime nextTime;
+  int nextTime;
 
   // work out if we're waiting for a timer,
   // and if so, when it's going to be
@@ -479,7 +499,7 @@ bool jstSetWakeUp(JsSysTime period) {
   }
   jshInterruptOn();
 
-  if (hasTimer && task.time >= nextTime) {
+  if (hasTimer && (task.time-utilTimerTime) >= (nextTime-utilTimerTime)) {
     // we already had a timer, and it's going to wake us up sooner.
     // don't create a WAKEUP timer task
     return true;
@@ -516,7 +536,7 @@ bool jstStartSignal(JsSysTime startTime, JsSysTime period, Pin pin, JsVar *curre
   if (!jshIsPinValid(pin)) return false;
   UtilTimerTask task;
   task.repeatInterval = (unsigned int)period;
-  task.time = startTime + period;
+  task.time = (int)(startTime + period);
   task.type = type;
   if (UET_IS_BUFFER_WRITE_EVENT(type)) {
     task.data.buffer.pinFunction = jshGetCurrentPinFunction(pin);
@@ -556,6 +576,8 @@ bool jstStopBufferTimerTask(JsVar *var) {
 void jstReset() {
   jshUtilTimerDisable();
   utilTimerTasksTail = utilTimerTasksHead = 0;
+  utilTimerTime = (int)jshGetSystemTime();
+  utilTimerPeriod = 0;
 }
 
 /** when system time is changed, also change the time in the timers.
@@ -566,6 +588,7 @@ void jstSystemTimeChanged(JsSysTime diff) {
     utilTimerTasks[t].time += diff;
     t = (t+1) & (UTILTIMERTASK_TASKS-1);
   }
+  utilTimerTime += diff;
 }
 
 void jstDumpUtilityTimers() {
@@ -576,23 +599,26 @@ void jstDumpUtilityTimers() {
     uTimerTasks[i] = utilTimerTasks[i];
   unsigned char uTimerTasksHead = utilTimerTasksHead;
   unsigned char uTimerTasksTail = utilTimerTasksTail;
+  int uTimerTime = utilTimerTime;
   jshInterruptOn();
 
+  jsiConsolePrintf("Current timer difference %d us", (int)(1000*jshGetMillisecondsFromTime(jshGetSystemTime()-uTimerTime)));
   unsigned char t = uTimerTasksTail;
   bool hadTimers = false;
   while (t!=uTimerTasksHead) {
     hadTimers = true;
 
     UtilTimerTask task = uTimerTasks[t];
-    jsiConsolePrintf("%08d us", (int)(1000*jshGetMillisecondsFromTime(task.time-jsiLastIdleTime)));
+    jsiConsolePrintf("%08d us", (int)(1000*jshGetMillisecondsFromTime(task.time-uTimerTime)));
     jsiConsolePrintf(", repeat %08d us", (int)(1000*jshGetMillisecondsFromTime(task.repeatInterval)));
     jsiConsolePrintf(" : ");
 
     switch (task.type) {
     case UET_WAKEUP : jsiConsolePrintf("WAKEUP\n"); break;
     case UET_SET : jsiConsolePrintf("SET ");
     for (i=0;i<UTILTIMERTASK_PIN_COUNT;i++)
-      jsiConsolePrintf("%p=%d,", task.data.set.pins[i],  (task.data.set.value>>i)&1);
+      if (task.data.set.pins[i] != PIN_UNDEFINED)
+        jsiConsolePrintf("%p=%d,", task.data.set.pins[i],  (task.data.set.value>>i)&1);
     jsiConsolePrintf("\n");
     break;
 #ifndef SAVE_ON_FLASH
@@ -609,4 +635,5 @@ void jstDumpUtilityTimers() {
   }
   if (!hadTimers)
       jsiConsolePrintf("No Timers found.\n");
+
 }
diff --git a/src/jstimer.h b/src/jstimer.h
@@ -89,7 +89,7 @@ typedef union UtilTimerTaskData {
 } UtilTimerTaskData;
 
 typedef struct UtilTimerTask {
-  JsSysTime time; // time at which to set pins
+  int time; // time at which to set pins (JshSysTime, cropped to 32 bits)
   unsigned int repeatInterval; // if nonzero, repeat the timer
   UtilTimerTaskData data; // data used when timer is hit
   UtilTimerEventType type; // the type of this task - do we set pin(s) or read/write data
