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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Jeff Epler for Adafruit Industries
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "common-hal/audiobusio/PDMIn.h"
#include "shared-bindings/microcontroller/Pin.h"
#include "py/runtime.h"
__attribute__((used))
NRF_PDM_Type *nrf_pdm = NRF_PDM;
static uint32_t dummy_buffer[4];
// Caller validates that pins are free.
void common_hal_audiobusio_pdmin_construct(audiobusio_pdmin_obj_t* self,
const mcu_pin_obj_t* clock_pin,
const mcu_pin_obj_t* data_pin,
uint32_t sample_rate,
uint8_t bit_depth,
bool mono,
uint8_t oversample) {
claim_pin(clock_pin);
claim_pin(data_pin);
self->mono = mono;
self->clock_pin_number = clock_pin->number;
self->data_pin_number = data_pin->number;
if (sample_rate != 16000) {
mp_raise_ValueError(translate("only sample_rate=16000 is supported"));
}
if (bit_depth != 16) {
mp_raise_ValueError(translate("only bit_depth=16 is supported"));
}
nrf_pdm->PSEL.CLK = self->clock_pin_number;
nrf_pdm->PSEL.DIN = self->data_pin_number;
nrf_pdm->PDMCLKCTRL = PDM_PDMCLKCTRL_FREQ_Default; // For Ratio64
nrf_pdm->RATIO = PDM_RATIO_RATIO_Ratio64;
nrf_pdm->GAINL = PDM_GAINL_GAINL_DefaultGain;
nrf_pdm->GAINR = PDM_GAINR_GAINR_DefaultGain;
nrf_pdm->ENABLE = 1;
nrf_pdm->SAMPLE.PTR = (uintptr_t)&dummy_buffer;
nrf_pdm->SAMPLE.MAXCNT = 1;
nrf_pdm->TASKS_START = 1;
}
bool common_hal_audiobusio_pdmin_deinited(audiobusio_pdmin_obj_t* self) {
return !self->clock_pin_number;
}
void common_hal_audiobusio_pdmin_deinit(audiobusio_pdmin_obj_t* self) {
nrf_pdm->ENABLE = 0;
reset_pin_number(self->clock_pin_number);
self->clock_pin_number = 0;
reset_pin_number(self->data_pin_number);
self->data_pin_number = 0;
}
uint8_t common_hal_audiobusio_pdmin_get_bit_depth(audiobusio_pdmin_obj_t* self) {
return 16;
}
uint32_t common_hal_audiobusio_pdmin_get_sample_rate(audiobusio_pdmin_obj_t* self) {
return 16000;
}
uint32_t common_hal_audiobusio_pdmin_record_to_buffer(audiobusio_pdmin_obj_t* self,
uint16_t* output_buffer, uint32_t output_buffer_length) {
// Note: Adafruit's module has SELECT pulled to GND, which makes the DATA
// valid when the CLK is low, therefore it must be sampled on the rising edge.
if (self->mono) {
nrf_pdm->MODE = PDM_MODE_OPERATION_Stereo | PDM_MODE_EDGE_LeftRising;
} else {
nrf_pdm->MODE = PDM_MODE_OPERATION_Mono | PDM_MODE_EDGE_LeftRising;
}
// step 1. Redirect to real buffer
nrf_pdm->SAMPLE.PTR = (uintptr_t)output_buffer;
nrf_pdm->SAMPLE.MAXCNT = output_buffer_length;
// a delay is the safest simple way to ensure that the above requested sample has started
mp_hal_delay_us(200);
nrf_pdm->EVENTS_END = 0;
// step 2. Registers are double buffered, so pre-redirect back to dummy buffer
nrf_pdm->SAMPLE.PTR = (uintptr_t)&dummy_buffer;
nrf_pdm->SAMPLE.MAXCNT = 1;
// Step 3. wait for PDM to end
while (!nrf_pdm->EVENTS_END) {
MICROPY_VM_HOOK_LOOP;
}
// Step 4. They want unsigned
for (uint32_t i=0; i<output_buffer_length; i++) {
output_buffer[i] += 32768;
}
if (self->mono) {
return (output_buffer_length / 2) * 2;
} else {
return (output_buffer_length / 4) * 4;
}
}
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