diff options
| author | Dan Halbert <halbert@halwitz.org> | 2020-06-19 15:05:51 -0400 |
|---|---|---|
| committer | Dan Halbert <halbert@halwitz.org> | 2020-06-19 15:25:04 -0400 |
| commit | 1687c8b1e38aa646639455e141c28e724da4d269 (patch) | |
| tree | ef0ce5bfc5ba11e8bc36a3a2bdd4762637c70a1a | |
| parent | 25d5f2cfc6097d4f49d955a69b964a7dc9fc5c52 (diff) | |
delay 1ms on SAMD51 when reading processor voltage
| -rw-r--r-- | ports/atmel-samd/common-hal/microcontroller/Processor.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/ports/atmel-samd/common-hal/microcontroller/Processor.c b/ports/atmel-samd/common-hal/microcontroller/Processor.c index 1e0b8fa79..2ca3ab30b 100644 --- a/ports/atmel-samd/common-hal/microcontroller/Processor.c +++ b/ports/atmel-samd/common-hal/microcontroller/Processor.c @@ -61,6 +61,7 @@ * POSSIBILITY OF SUCH DAMAGE. */ +#include "py/mphal.h" #include "common-hal/microcontroller/Processor.h" #include "samd/adc.h" @@ -286,11 +287,15 @@ float common_hal_mcu_processor_get_voltage(void) { #ifdef SAMD51 hri_supc_set_VREF_SEL_bf(SUPC, SUPC_VREF_SEL_1V0_Val); - // ONDEMAND must be clear, and VREFOE must be set, or else the ADC conversion will not complete. - // See https://community.atmel.com/forum/samd51-using-intref-adc-voltage-reference - hri_supc_clear_VREF_ONDEMAND_bit(SUPC); hri_supc_set_VREF_VREFOE_bit(SUPC); + adc_sync_set_reference(&adc, ADC_REFCTRL_REFSEL_INTREF_Val); + + // On some processor samples, the ADC will hang trying to read the voltage. A simple + // delay after setting the SUPC bits seems to fix things. This appears to be due to VREFOE + // startup time. There is no synchronization bit to check. + // See https://community.atmel.com/forum/samd51-using-intref-adc-voltage-reference + mp_hal_delay_ms(1); #endif adc_sync_set_resolution(&adc, ADC_CTRLB_RESSEL_12BIT_Val); |