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Add analogin driver for CM3DS MPS2 target
This patch adds analogin driver for CM3DS MPS2 target. Signed-off-by: Hugues de Valon <[email protected]>
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‎targets/TARGET_ARM_SSG/TARGET_CM3DS_MPS2/analogin_api.c

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/* mbed Microcontroller Library
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* Copyright (c) 2017 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* This HAL implementation uses the AD7490 analog-to-digital converter
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* available on the MPS2 Adapter for Arduino shields.
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*/
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#include "analogin_api.h"
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#include "gpio_api.h"
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#include "spi_api.h"
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#include "mbed_error.h"
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#include "mbed_wait_api.h"
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#include "pinmap.h"
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/*
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* There is only one AD7490 controller to read the analog pins in both shields.
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* The AD7490 documentation (AD7490.pdf, page 12) tells us the right control
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* register to send.
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*/
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/* Output conversion is straight binary */
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#define CODING (1 << 0)
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/* Analog input range from 0 to REF_IN volts */
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#define RANGE (1 << 1)
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/* DOUT line state, weakly driven or three-state */
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#define WEAK_TRI (1 << 2)
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/* Access to the shadow register */
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#define SHADOW (1 << 3)
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/* Normal operation power mode */
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#define PM0 (1 << 4)
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/* Normal operation power mode */
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#define PM1 (1 << 5)
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/* Write control register */
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#define WRITE (1 << 11)
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#define NORMAL_CONTROL_REGISTER (CODING | RANGE | PM0 | PM1 | WRITE)
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/* The ADC will ignore the write of this control register */
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#define NO_WRITE_CONTROL_REGISTER 0x000
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/* Bit position of the channel number in the control register */
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#define CHANNEL_NUMBER_POSITION 6
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/* CS signal of the ADC needs to be put low during transfers */
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#define CS_LOW 0
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#define CS_HIGH 1
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/* The ADC expects a 16 bits word but only read the 12 most significant bits */
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#define USELESS_ADC_BITS 4
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/* The ADC result is on the 12 least significant bits */
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#define OUTPUT_DATA_MASK 0xFFF
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/* The maximum value is the biggest value than can be coded on 12 bits */
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#define MAXIMUM_VALUE_12_BITS OUTPUT_DATA_MASK
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#define FRAME_16_BITS 16
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#define NO_POLARITY_NO_PHASE 0
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#define MASTER_MODE 0
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/* Maximal SPI frequency as written in the ADC documentation */
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#define MAXIMAL_SPI_FREQUENCY_HZ 12000000
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/* The value of the peripheral constant linked with one analog pins is the
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* channel number of that pin on the ADC:
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* A0_0 is channel 0
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* ...
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* A0_5 is channel 5
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* A1_0 is channel 6
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* ...
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* A1_5 is channel 11
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*/
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static const PinMap PinMap_ADC[] = {
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{A0_0, ADC0_0, 0},
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{A0_1, ADC0_1, 0},
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{A0_2, ADC0_2, 0},
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{A0_3, ADC0_3, 0},
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{A0_4, ADC0_4, 0},
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{A0_5, ADC0_5, 0},
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{A1_0, ADC0_6, 0},
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{A1_1, ADC0_7, 0},
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{A1_2, ADC0_8, 0},
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{A1_3, ADC0_9, 0},
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{A1_4, ADC0_10, 0},
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{A1_5, ADC0_11, 0},
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{NC , NC, 0}
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};
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/* mbed OS gpio_t structure for the CS pin linked to the ADC */
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static gpio_t adc_cs;
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/* mbed OS spi_t structure to communicate with the ADC */
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static spi_t adc_spi;
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void analogin_init(analogin_t *obj, PinName pin)
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{
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uint16_t control_register = NORMAL_CONTROL_REGISTER;
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uint32_t channel_number = pinmap_peripheral(pin, PinMap_ADC);
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if (channel_number == (uint32_t)NC) {
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error("pin %d is not connected to the ADC", pin);
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}
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/* Add the channel number to the control register */
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control_register |= (channel_number << CHANNEL_NUMBER_POSITION);
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/* Only the 12 first bits are taken into account */
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control_register <<= USELESS_ADC_BITS;
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obj->ctrl_register = control_register;
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spi_init(&adc_spi, ADC_MOSI, ADC_MISO, ADC_SCLK, NC);
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spi_format(&adc_spi, FRAME_16_BITS, NO_POLARITY_NO_PHASE, MASTER_MODE);
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spi_frequency(&adc_spi, MAXIMAL_SPI_FREQUENCY_HZ);
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gpio_init_out(&adc_cs, ADC_SSEL);
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}
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uint16_t analogin_read_u16(analogin_t *obj)
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{
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uint16_t result;
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/* Request conversion */
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gpio_write(&adc_cs, CS_LOW);
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/* Only write the control register, ignore the previous results */
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(void)spi_master_write(&adc_spi, obj->ctrl_register);
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gpio_write(&adc_cs, CS_HIGH);
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/*
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* According to the documentation, t_QUIET (50 ns) time needs to pass before
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* accessing to the SPI bus again. We wait here 1 us as we can not wait a
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* shorter time than that.
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*/
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wait_us(1);
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/* Read conversion result */
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gpio_write(&adc_cs, CS_LOW);
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/* Only read the results without writing the control register */
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result = spi_master_write(&adc_spi, NO_WRITE_CONTROL_REGISTER);
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gpio_write(&adc_cs, CS_HIGH);
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return (result & OUTPUT_DATA_MASK);
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}
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float analogin_read(analogin_t *obj)
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{
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uint16_t result = analogin_read_u16(obj);
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return (result * (1. / MAXIMUM_VALUE_12_BITS));
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}

‎targets/TARGET_ARM_SSG/TARGET_CM3DS_MPS2/objects.h

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};
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struct analogin_s {
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ADCName adc;
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MPS2_SSP_TypeDef *adc_spi;
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PinName pin;
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uint32_t pin_number;
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__IO uint32_t address;
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uint16_t ctrl_register; /* Control bits with the channel identifier */
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};
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#include "gpio_object.h"

‎targets/targets.json

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"supported_toolchains": ["ARM", "GCC_ARM", "IAR"],
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"extra_labels": ["ARM_SSG", "CM3DS_MPS2"],
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"macros": ["CMSDK_CM3DS"],
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"device_has": ["ETHERNET", "I2C", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "SERIAL", "SPI", "RTC"],
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"device_has": ["ANALOGIN", "ETHERNET", "I2C", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "SERIAL", "SPI", "RTC"],
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"release_versions": ["2", "5"]
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},
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"ARM_BEETLE_SOC": {

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