167 lines
6.4 KiB
C
167 lines
6.4 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) 2016 Scott Shawcroft 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/analogio/AnalogIn.h"
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#include <string.h>
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#include "py/gc.h"
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#include "py/nlr.h"
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#include "py/runtime.h"
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#include "py/binary.h"
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#include "py/mphal.h"
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#include "shared-bindings/analogio/AnalogIn.h"
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#include "atmel_start_pins.h"
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#include "hal/include/hal_adc_sync.h"
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#include "hpl/gclk/hpl_gclk_base.h"
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#ifdef SAMD21
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#include "hpl/pm/hpl_pm_base.h"
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#endif
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void common_hal_analogio_analogin_construct(analogio_analogin_obj_t* self,
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const mcu_pin_obj_t *pin) {
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uint8_t adc_index;
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uint8_t adc_channel = 0xff;
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for (adc_index = 0; adc_index < NUM_ADC_PER_PIN; adc_index++) {
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// TODO(tannewt): Only use ADC0 on the SAMD51 when touch isn't being
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// used.
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if (pin->adc_input[adc_index] != 0xff) {
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adc_channel = pin->adc_input[adc_index];
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break;
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}
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}
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if (adc_channel == 0xff) {
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// No ADC function on that pin
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mp_raise_ValueError("Pin does not have ADC capabilities");
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}
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claim_pin(pin);
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gpio_set_pin_function(pin->pin, GPIO_PIN_FUNCTION_B);
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static Adc* adc_insts[] = ADC_INSTS;
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self->instance = adc_insts[adc_index];
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self->channel = adc_channel;
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self->pin = pin;
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}
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bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
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return self->pin == mp_const_none;
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}
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void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self) {
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if (common_hal_analogio_analogin_deinited(self)) {
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return;
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}
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reset_pin(self->pin->pin);
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self->pin = mp_const_none;
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}
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void analogin_reset() {
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}
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uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
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// Something else might have used the ADC in a different way,
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// so we completely re-initialize it.
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// Turn the clocks on.
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#ifdef SAMD51
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if (self->instance == ADC0) {
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hri_mclk_set_APBDMASK_ADC0_bit(MCLK);
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hri_gclk_write_PCHCTRL_reg(GCLK, ADC0_GCLK_ID, GCLK_PCHCTRL_GEN_GCLK1_Val | (1 << GCLK_PCHCTRL_CHEN_Pos));
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} else if (self->instance == ADC1) {
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hri_mclk_set_APBDMASK_ADC1_bit(MCLK);
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hri_gclk_write_PCHCTRL_reg(GCLK, ADC1_GCLK_ID, GCLK_PCHCTRL_GEN_GCLK1_Val | (1 << GCLK_PCHCTRL_CHEN_Pos));
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}
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#endif
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#ifdef SAMD21
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_pm_enable_bus_clock(PM_BUS_APBC, ADC);
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_gclk_enable_channel(ADC_GCLK_ID, GCLK_CLKCTRL_GEN_GCLK0_Val);
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#endif
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struct adc_sync_descriptor adc;
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adc_sync_init(&adc, self->instance, (void *)NULL);
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adc_sync_set_reference(&adc, ADC_REFCTRL_REFSEL_INTVCC1_Val);
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adc_sync_set_resolution(&adc, ADC_CTRLB_RESSEL_12BIT_Val);
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#ifdef SAMD21
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adc_sync_set_channel_gain(&adc, self->channel, ADC_INPUTCTRL_GAIN_DIV2_Val);
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// Load the factory calibration
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hri_adc_write_CALIB_BIAS_CAL_bf(ADC, (*((uint32_t*) ADC_FUSES_BIASCAL_ADDR) & ADC_FUSES_BIASCAL_Msk) >> ADC_FUSES_BIASCAL_Pos);
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// Bits 7:5
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uint16_t linearity = ((*((uint32_t*) ADC_FUSES_LINEARITY_1_ADDR) & ADC_FUSES_LINEARITY_1_Msk) >> ADC_FUSES_LINEARITY_1_Pos) << 5;
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// Bits 4:0
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linearity |= (*((uint32_t*) ADC_FUSES_LINEARITY_0_ADDR) & ADC_FUSES_LINEARITY_0_Msk) >> ADC_FUSES_LINEARITY_0_Pos;
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hri_adc_write_CALIB_LINEARITY_CAL_bf(ADC, linearity);
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#endif
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// SAMD51 has a CALIB register but doesn't have documented fuses for them.
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#ifdef SAMD51
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uint8_t biasrefbuf;
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uint8_t biasr2r;
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uint8_t biascomp;
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if (self->instance == ADC0) {
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biasrefbuf = ((*(uint32_t*) ADC0_FUSES_BIASREFBUF_ADDR) & ADC0_FUSES_BIASREFBUF_Msk) >> ADC0_FUSES_BIASREFBUF_Pos;
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biasr2r = ((*(uint32_t*) ADC0_FUSES_BIASR2R_ADDR) & ADC0_FUSES_BIASR2R_Msk) >> ADC0_FUSES_BIASR2R_Pos;
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biascomp = ((*(uint32_t*) ADC0_FUSES_BIASCOMP_ADDR) & ADC0_FUSES_BIASCOMP_Msk) >> ADC0_FUSES_BIASCOMP_Pos;
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} else {
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biasrefbuf = ((*(uint32_t*) ADC1_FUSES_BIASREFBUF_ADDR) & ADC1_FUSES_BIASREFBUF_Msk) >> ADC1_FUSES_BIASREFBUF_Pos;
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biasr2r = ((*(uint32_t*) ADC1_FUSES_BIASR2R_ADDR) & ADC1_FUSES_BIASR2R_Msk) >> ADC1_FUSES_BIASR2R_Pos;
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biascomp = ((*(uint32_t*) ADC1_FUSES_BIASCOMP_ADDR) & ADC1_FUSES_BIASCOMP_Msk) >> ADC1_FUSES_BIASCOMP_Pos;
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}
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hri_adc_write_CALIB_BIASREFBUF_bf(self->instance, biasrefbuf);
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hri_adc_write_CALIB_BIASR2R_bf(self->instance, biasr2r);
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hri_adc_write_CALIB_BIASCOMP_bf(self->instance, biascomp);
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#endif
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adc_sync_enable_channel(&adc, self->channel);
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// We need to set the inputs because the above channel enable only enables the ADC.
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adc_sync_set_inputs(&adc, self->channel, ADC_INPUTCTRL_MUXNEG_GND_Val, self->channel);
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// Read twice and discard first result, as recommended in section 14 of
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// http://www.atmel.com/images/Atmel-42645-ADC-Configurations-with-Examples_ApplicationNote_AT11481.pdf
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// "Discard the first conversion result whenever there is a change in ADC configuration
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// like voltage reference / ADC channel change"
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// Empirical observation shows the first reading is quite different than subsequent ones.
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uint16_t value;
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adc_sync_read_channel(&adc, self->channel, ((uint8_t*) &value), 2);
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adc_sync_read_channel(&adc, self->channel, ((uint8_t*) &value), 2);
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adc_sync_deinit(&adc);
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// Shift the value to be 16 bit.
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return value << 4;
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}
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float common_hal_analogio_analogin_get_reference_voltage(analogio_analogin_obj_t *self) {
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return 3.3f;
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}
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