Replace micros for one using CycCntteensy4-core
@@ -336,8 +336,10 @@ void MillisTimer::runFromTimer() | |||
// TODO: this doesn't work for IMXRT - no longer using predefined names | |||
extern "C" volatile uint32_t systick_millis_count; | |||
extern "C" volatile uint32_t systick_cycle_count; | |||
extern "C" void systick_isr(void) | |||
{ | |||
systick_cycle_count += F_CPU_ACTUAL/1000; | |||
systick_millis_count++; | |||
MillisTimer::runFromTimer(); | |||
} |
@@ -3,6 +3,7 @@ | |||
//volatile uint32_t F_CPU = 396000000; | |||
//volatile uint32_t F_BUS = 132000000; | |||
volatile uint32_t systick_millis_count = 0; | |||
volatile uint32_t systick_cycle_count = 0; | |||
// page 411 says "24 MHz XTALOSC can be the external clock source of SYSTICK" | |||
// Testing shows the frequency is actually 100 kHz - but how? Did NXP really | |||
@@ -62,6 +63,19 @@ void delay(uint32_t msec) | |||
} | |||
uint32_t micros(void) | |||
{ | |||
uint32_t ccdelta, usec, smc; | |||
do { | |||
smc = systick_millis_count; | |||
ccdelta = ARM_DWT_CYCCNT - systick_cycle_count; | |||
} while ( smc != systick_millis_count ); // repeat if systick_isr | |||
usec = 1000*smc + (ccdelta/(F_CPU_ACTUAL/1000000)); | |||
return usec; | |||
} | |||
#if 0 // kept to compare test to cycle count micro() | |||
extern uint32_t otmicros(void); | |||
uint32_t otmicros(void) | |||
{ | |||
uint32_t msec, tick, elapsed, istatus, usec; | |||
//static uint32_t prev_msec=0; | |||
@@ -118,4 +132,4 @@ uint32_t micros(void) | |||
prev_usec = usec; | |||
return usec; | |||
} | |||
#endif |
@@ -111,16 +111,28 @@ void ResetHandler(void) | |||
// the ARM clock to run at different speeds. | |||
#define SYSTICK_EXT_FREQ 100000 | |||
extern volatile uint32_t systick_cycle_count; | |||
#define MAGIC_VAL 5 // empiric start value syncs signif. digits to millis() | |||
static void systick_isr_sync(void) | |||
{ | |||
// 1st[0] tick is sync baseline CycCnt for micros() | |||
if ( 0 == systick_millis_count ) | |||
systick_cycle_count = ARM_DWT_CYCCNT - MAGIC_VAL*F_CPU_ACTUAL/1000; | |||
else | |||
_VectorsRam[15] = systick_isr; // use CORE _isr | |||
systick_millis_count++; | |||
} | |||
static void configure_systick(void) | |||
{ | |||
_VectorsRam[14] = pendablesrvreq_isr; | |||
_VectorsRam[15] = systick_isr; | |||
_VectorsRam[15] = systick_isr_sync; // Wait for CycleCounter to sync | |||
SYST_RVR = (SYSTICK_EXT_FREQ / 1000) - 1; | |||
SYST_CVR = 0; | |||
SYST_CSR = SYST_CSR_TICKINT | SYST_CSR_ENABLE; | |||
SCB_SHPR3 = 0x20000000; // Systick = priority 32 | |||
ARM_DEMCR |= ARM_DEMCR_TRCENA; | |||
ARM_DWT_CTRL |= ARM_DWT_CTRL_CYCCNTENA; // turn on cycle counter | |||
systick_cycle_count = ARM_DWT_CYCCNT; // was 0, must sync w/_isr | |||
} | |||
@@ -246,6 +258,7 @@ void usb_pll_start() | |||
// R2 | |||
// R1 | |||
// R0 | |||
__attribute__((weak)) | |||
void unused_interrupt_vector(void) | |||
{ | |||
// TODO: polling Serial to complete buffered transmits |