Power-efficient crank

src/crank.c

@@ -27,6 +27,7 @@ static void update(srv_t *state) {
 static void maybe_init(srv_t *state) {
     if (state->is_streaming && !state->inited) {
         state->inited = true;
+        tim_max_sleep = 1000;
         pin_setup_input(state->pin0, 1);
         pin_setup_input(state->pin1, 1);
         update(state);
@@ -36,7 +37,7 @@ static void maybe_init(srv_t *state) {
 void crank_process(srv_t *state) {
     maybe_init(state);
 
-    if (should_sample(&state->nextSample, 997) && state->inited)
+    if (should_sample(&state->nextSample, 950) && state->inited)
         update(state);
 
     sensor_process_simple(state, &state->sample, sizeof(state->sample));

src/tinyhw.h

@@ -38,4 +38,5 @@ RAM_FUNC
 void target_wait_cycles(int n);
 int target_in_irq(void);
 
-extern uint8_t cpu_mhz;
+extern uint8_t cpu_mhz;
+extern uint16_t tim_max_sleep;

stm32/tim.c

@@ -8,6 +8,8 @@
 static volatile uint64_t timeoff;
 static volatile cb_t timer_cb;
 
+uint16_t tim_max_sleep;
+
 // takes around 1us
 uint64_t tim_get_micros() {
     while (1) {
@@ -42,6 +44,9 @@ void tim_set_timer(int delta, cb_t cb) {
     if (delta < 10)
         delta = 10;
 
+    if (tim_max_sleep && delta == 10000)
+        delta = tim_max_sleep;
+
     rtc_cancel_cb();
     target_disable_irq();
     timer_cb = cb;