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fix off-by-one PWM top issue

This commit is contained in:
Dan Halbert 2021-02-12 15:34:36 -05:00
parent 766e79ad3d
commit 3e4328140c
3 changed files with 11 additions and 11 deletions
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17
ports/raspberrypi/common-hal/pwmio/PWMOut.c
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@ -164,7 +164,8 @@ void common_hal_pwmio_pwmout_deinit(pwmio_pwmout_obj_t* self) {
extern void common_hal_pwmio_pwmout_set_duty_cycle(pwmio_pwmout_obj_t* self, uint16_t duty) { extern void common_hal_pwmio_pwmout_set_duty_cycle(pwmio_pwmout_obj_t* self, uint16_t duty) {
self->duty_cycle = duty; self->duty_cycle = duty;
uint16_t actual_duty = duty * self->top / ((1 << 16) - 1); // Do arithmetic in 32 bits to prevent overflow.
uint16_t actual_duty = (uint32_t) duty * self->top / ((1 << 16) - 1);
pwm_set_chan_level(self->slice, self->channel, actual_duty); pwm_set_chan_level(self->slice, self->channel, actual_duty);
} }
@ -172,11 +173,11 @@ uint16_t common_hal_pwmio_pwmout_get_duty_cycle(pwmio_pwmout_obj_t* self) {
return self->duty_cycle; return self->duty_cycle;
} }
void pwmio_pwmout_set_top(pwmio_pwmout_obj_t* self, uint32_t top) { void pwmio_pwmout_set_top(pwmio_pwmout_obj_t* self, uint16_t top) {
self->actual_frequency = common_hal_mcu_processor_get_frequency() / top; self->actual_frequency = common_hal_mcu_processor_get_frequency() / top;
self->top = top; self->top = top;
pwm_set_clkdiv_int_frac(self->slice, 1, 0); pwm_set_clkdiv_int_frac(self->slice, 1, 0);
pwm_set_wrap(self->slice, self->top - 1); pwm_set_wrap(self->slice, self->top);
} }
void common_hal_pwmio_pwmout_set_frequency(pwmio_pwmout_obj_t* self, uint32_t frequency) { void common_hal_pwmio_pwmout_set_frequency(pwmio_pwmout_obj_t* self, uint32_t frequency) {
@ -187,7 +188,7 @@ void common_hal_pwmio_pwmout_set_frequency(pwmio_pwmout_obj_t* self, uint32_t fr
target_slice_frequencies[self->slice] = frequency; target_slice_frequencies[self->slice] = frequency;
// For low frequencies use the divider to give us full resolution duty_cycle. // For low frequencies use the divider to give us full resolution duty_cycle.
if (frequency < (common_hal_mcu_processor_get_frequency() / (1 << 16))) { if (frequency <= (common_hal_mcu_processor_get_frequency() / (1 << 16))) {
// Compute the divisor. It's an 8 bit integer and 4 bit fraction. Therefore, // Compute the divisor. It's an 8 bit integer and 4 bit fraction. Therefore,
// we compute everything * 16 for the fractional part. // we compute everything * 16 for the fractional part.
// This is 1 << 12 because 4 bits are the * 16. // This is 1 << 12 because 4 bits are the * 16.
@ -202,15 +203,15 @@ void common_hal_pwmio_pwmout_set_frequency(pwmio_pwmout_obj_t* self, uint32_t fr
div16 = (1 << 12) - 1; div16 = (1 << 12) - 1;
} }
self->actual_frequency = frequency16 / div16; self->actual_frequency = frequency16 / div16;
self->top = 1 << 16; self->top = (1 << 16) - 1;
pwm_set_clkdiv_int_frac(self->slice, div16 / 16, div16 % 16); pwm_set_clkdiv_int_frac(self->slice, div16 / 16, div16 % 16);
pwm_set_wrap(self->slice, self->top - 1); pwm_set_wrap(self->slice, self->top);
} else { } else {
uint32_t top = common_hal_mcu_processor_get_frequency() / frequency; uint32_t top = common_hal_mcu_processor_get_frequency() / frequency;
self->actual_frequency = common_hal_mcu_processor_get_frequency() / top; self->actual_frequency = common_hal_mcu_processor_get_frequency() / top;
self->top = top; self->top = MIN(UINT16_MAX, top - 1);
pwm_set_clkdiv_int_frac(self->slice, 1, 0); pwm_set_clkdiv_int_frac(self->slice, 1, 0);
pwm_set_wrap(self->slice, self->top - 1); pwm_set_wrap(self->slice, self->top);
} }
common_hal_pwmio_pwmout_set_duty_cycle(self, self->duty_cycle); common_hal_pwmio_pwmout_set_duty_cycle(self, self->duty_cycle);
} }

4
ports/raspberrypi/common-hal/pwmio/PWMOut.h
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@ -39,11 +39,11 @@ typedef struct {
bool variable_frequency; bool variable_frequency;
uint16_t duty_cycle; uint16_t duty_cycle;
uint32_t actual_frequency; uint32_t actual_frequency;
uint32_t top; uint16_t top;
} pwmio_pwmout_obj_t; } pwmio_pwmout_obj_t;
void pwmout_reset(void); void pwmout_reset(void);
// Private API for AudioPWMOut. // Private API for AudioPWMOut.
void pwmio_pwmout_set_top(pwmio_pwmout_obj_t* self, uint32_t top); void pwmio_pwmout_set_top(pwmio_pwmout_obj_t* self, uint16_t top);
#endif // MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_PWMIO_PWMOUT_H #endif // MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_PWMIO_PWMOUT_H

1
shared-bindings/adafruit_bus_device/SPIDevice.c
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@ -34,7 +34,6 @@
#include "lib/utils/buffer_helper.h" #include "lib/utils/buffer_helper.h"
#include "lib/utils/context_manager_helpers.h" #include "lib/utils/context_manager_helpers.h"
#include "py/objproperty.h"
#include "py/runtime.h" #include "py/runtime.h"
#include "supervisor/shared/translate.h" #include "supervisor/shared/translate.h"