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use nrf_pwm instead of direct registers

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This commit is contained in:
hathach 2018-09-05 13:18:36 +07:00
parent f4a98e909c
commit ccd87a33b6
2 changed files with 39 additions and 29 deletions
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57
ports/nrf/common-hal/neopixel_write/__init__.c
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@ -26,6 +26,7 @@
#include "py/mphal.h"
#include "shared-bindings/neopixel_write/__init__.h"
#include "nrf_pwm.h"
// https://github.com/adafruit/Adafruit_NeoPixel/blob/master/Adafruit_NeoPixel.cpp
// [[[Begin of the Neopixel NRF52 EasyDMA implementation
@ -76,13 +77,17 @@
// find a free PWM device, which is not enabled and has no connected pins
static NRF_PWM_Type* find_free_pwm (void) {
NRF_PWM_Type* PWM[3] = { NRF_PWM0, NRF_PWM1, NRF_PWM2 };
NRF_PWM_Type* PWM[] = {
NRF_PWM0, NRF_PWM1, NRF_PWM2
#ifdef NRF_PWM3
, NRF_PWM3
#endif
};
for ( int device = 0; device < 3; device++ ) {
if ( (PWM[device]->ENABLE == 0) && (PWM[device]->PSEL.OUT[0] & PWM_PSEL_OUT_CONNECT_Msk)
&& (PWM[device]->PSEL.OUT[1] & PWM_PSEL_OUT_CONNECT_Msk)
&& (PWM[device]->PSEL.OUT[2] & PWM_PSEL_OUT_CONNECT_Msk)
&& (PWM[device]->PSEL.OUT[3] & PWM_PSEL_OUT_CONNECT_Msk) ) {
for ( int device = 0; device < ARRAY_SIZE(PWM); device++ ) {
if ( (PWM[device]->ENABLE == 0) &&
(PWM[device]->PSEL.OUT[0] & PWM_PSEL_OUT_CONNECT_Msk) && (PWM[device]->PSEL.OUT[1] & PWM_PSEL_OUT_CONNECT_Msk) &&
(PWM[device]->PSEL.OUT[2] & PWM_PSEL_OUT_CONNECT_Msk) && (PWM[device]->PSEL.OUT[3] & PWM_PSEL_OUT_CONNECT_Msk) ) {
return PWM[device];
}
}
@ -130,34 +135,28 @@ void common_hal_neopixel_write (const digitalio_digitalinout_obj_t* digitalinout
pixels_pattern[++pos] = 0 | (0x8000); // Seq end
// Set the wave mode to count UP
pwm->MODE = (PWM_MODE_UPDOWN_Up << PWM_MODE_UPDOWN_Pos);
// Set the PWM to use the 16MHz clock
pwm->PRESCALER = (PWM_PRESCALER_PRESCALER_DIV_1 << PWM_PRESCALER_PRESCALER_Pos);
// Setting of the maximum count
// but keeping it on 16Mhz allows for more granularity just
// in case someone wants to do more fine-tuning of the timing.
pwm->COUNTERTOP = (CTOPVAL << PWM_COUNTERTOP_COUNTERTOP_Pos);
nrf_pwm_configure(pwm, NRF_PWM_CLK_16MHz, NRF_PWM_MODE_UP, CTOPVAL);
// Disable loops, we want the sequence to repeat only once
pwm->LOOP = (PWM_LOOP_CNT_Disabled << PWM_LOOP_CNT_Pos);
nrf_pwm_loop_set(pwm, 0);
// On the "Common" setting the PWM uses the same pattern for the
// for supported sequences. The pattern is stored on half-word
// of 16bits
pwm->DECODER = (PWM_DECODER_LOAD_Common << PWM_DECODER_LOAD_Pos)
| (PWM_DECODER_MODE_RefreshCount << PWM_DECODER_MODE_Pos);
// for supported sequences. The pattern is stored on half-word of 16bits
nrf_pwm_decoder_set(pwm, PWM_DECODER_LOAD_Common, PWM_DECODER_MODE_RefreshCount);
// Pointer to the memory storing the patter
pwm->SEQ[0].PTR = (uint32_t) (pixels_pattern) << PWM_SEQ_PTR_PTR_Pos;
// Pointer to the memory storing the pattern
nrf_pwm_seq_ptr_set(pwm, 0, pixels_pattern);
// Calculation of the number of steps loaded from memory.
pwm->SEQ[0].CNT = (pattern_size / sizeof(uint16_t)) << PWM_SEQ_CNT_CNT_Pos;
nrf_pwm_seq_cnt_set(pwm, 0, pattern_size / sizeof(uint16_t));
// The following settings are ignored with the current config.
pwm->SEQ[0].REFRESH = 0;
pwm->SEQ[0].ENDDELAY = 0;
nrf_pwm_seq_refresh_set(pwm, 0, 0);
nrf_pwm_seq_end_delay_set(pwm, 0, 0);
// The Neopixel implementation is a blocking algorithm. DMA
// allows for non-blocking operation. To "simulate" a blocking
@ -167,32 +166,32 @@ void common_hal_neopixel_write (const digitalio_digitalinout_obj_t* digitalinout
// pwm->INTEN |= (PWM_INTEN_SEQEND0_Enabled<<PWM_INTEN_SEQEND0_Pos);
// PSEL must be configured before enabling PWM
pwm->PSEL.OUT[0] = ( digitalinout->pin->port*32 + digitalinout->pin->pin );
nrf_pwm_pins_set(pwm, (uint32_t[]) {digitalinout->pin->port*32 + digitalinout->pin->pin, 0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFFUL} );
// Enable the PWM
pwm->ENABLE = 1;
nrf_pwm_enable(pwm);
// After all of this and many hours of reading the documentation
// we are ready to start the sequence...
pwm->EVENTS_SEQEND[0] = 0;
pwm->TASKS_SEQSTART[0] = 1;
nrf_pwm_event_clear(pwm, NRF_PWM_EVENT_SEQEND0);
nrf_pwm_task_trigger(pwm, NRF_PWM_TASK_SEQSTART0);
// But we have to wait for the flag to be set.
while ( !pwm->EVENTS_SEQEND[0] ) {
while ( !nrf_pwm_event_check(pwm, NRF_PWM_EVENT_SEQEND0) ) {
#ifdef MICROPY_VM_HOOK_LOOP
MICROPY_VM_HOOK_LOOP
#endif
}
// Before leave we clear the flag for the event.
pwm->EVENTS_SEQEND[0] = 0;
nrf_pwm_event_clear(pwm, NRF_PWM_EVENT_SEQEND0);
// We need to disable the device and disconnect
// all the outputs before leave or the device will not
// be selected on the next call.
// TODO: Check if disabling the device causes performance issues.
pwm->ENABLE = 0;
pwm->PSEL.OUT[0] = 0xFFFFFFFFUL;
nrf_pwm_disable(pwm);
nrf_pwm_pins_set(pwm, (uint32_t[]) {0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFFUL} );
m_free(pixels_pattern);
} // End of DMA implementation

11
ports/nrf/nrfx_config.h
View File

@ -34,4 +34,15 @@
#define NRFX_UART_DEFAULT_CONFIG_PARITY NRF_UART_PARITY_EXCLUDED
#define NRFX_UART_DEFAULT_CONFIG_BAUDRATE NRF_UART_BAUDRATE_115200
// PWM
#define NRFX_PWM0_ENABLED 1
#define NRFX_PWM1_ENABLED 1
#define NRFX_PWM2_ENABLED 1
#ifdef NRF_PWM3
#define NRFX_PWM3_ENABLED 1
#else
#define NRFX_PWM3_ENABLED 0
#endif
#endif