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