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Merge pull request #410 from UncleRus/extras/ad770x

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Driver for AD7705/AD7706 SPI ADC
This commit is contained in:
Ruslan V. Uss 2017-07-10 03:42:42 +05:00 committed by GitHub
commit e17b1a5db6
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4
examples/ad770x/Makefile Normal file
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PROGRAM = ad770x
EXTRA_COMPONENTS = extras/ad770x
#ESPBAUD = 460800
include ../../common.mk

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examples/ad770x/main.c Normal file
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/*
* Example of using AD7705/AD7706 driver
*
* Part of esp-open-rtos
* Copyright (C) 2017 Ruslan V. Uss <unclerus@gmail.com>
* BSD Licensed as described in the file LICENSE
*/
#include <esp/uart.h>
#include <espressif/esp_common.h>
#include <stdio.h>
#include <i2c/i2c.h>
#include <ad770x/ad770x.h>
#include <FreeRTOS.h>
#include <task.h>
#define CS_PIN 2
#define AIN_CHANNEL 0 // AIN1+,AIN1- for AD7705
static const ad770x_params_t dev = {
.cs_pin = CS_PIN,
.master_clock = AD770X_MCLK_4_9152MHz, // 4.9152 MHz
.bipolar = false, // Unipolar mode
.gain = AD770X_GAIN_1, // No gain
.update_rate = AD770X_RATE_50 // 50 Hz output update rate
};
void user_init(void)
{
uart_set_baud(0, 115200);
printf("SDK version:%s\n", sdk_system_get_sdk_version());
while (ad770x_init(&dev, AIN_CHANNEL) != 0)
{
printf("Cannot initialize AD7705\n");
vTaskDelay(500 / portTICK_PERIOD_MS);
}
while (true)
{
// wait for data
while (!ad770x_data_ready(&dev, AIN_CHANNEL)) {}
// Read result
uint16_t raw = ad770x_raw_adc_value(&dev, AIN_CHANNEL);
printf("Raw ADC value: %d\n", raw);
vTaskDelay(500 / portTICK_PERIOD_MS);
}
}

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extras/ad770x/ad770x.c Normal file
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/**
* Driver for AD7705/AD7706 SPI ADC
*
* Part of esp-open-rtos
* Copyright (C) 2017 Ruslan V. Uss <unclerus@gmail.com>
* BSD Licensed as described in the file LICENSE
*/
#include "ad770x.h"
#include <errno.h>
#include <esp/gpio.h>
#include <esp/spi.h>
#include <espressif/esp_common.h>
#define AD770X_DEBUG
#define BUS 1
#define INIT_TIMEOUT 500000 // 500ms
#ifdef AD770X_DEBUG
#include <stdio.h>
#define debug(fmt, ...) printf("%s" fmt "\n", "AD770x: ", ## __VA_ARGS__)
#else
#define debug(fmt, ...)
#endif
#define timeout_expired(start, len) ((uint32_t)(sdk_system_get_time() - (start)) >= (len))
#define _BV(x) (1 << (x))
#define REG_COMM 0x00 // 8 bits
#define REG_SETUP 0x01 // 8 bits
#define REG_CLOCK 0x02 // 8 bits
#define REG_DATA 0x03 // 16 bits
#define REG_TEST 0x04 // 8 bits
#define REG_OFFS 0x06 // 24 bits
#define REG_GAIN 0x07 // 24 bits
#define BIT_COMM_CH0 0
#define BIT_COMM_CH1 1
#define BIT_COMM_STBY 2
#define BIT_COMM_RW 3
#define BIT_COMM_RS0 4
#define BIT_COMM_RS1 5
#define BIT_COMM_RS2 6
#define BIT_COMM_DRDY 7
#define MASK_COMM_CH 0x03
#define MASK_COMM_RS 0x70
#define BIT_CLOCK_FS0 0
#define BIT_CLOCK_FS1 1
#define BIT_CLOCK_CLK 2
#define BIT_CLOCK_CLKDIV 3
#define BIT_CLOCK_CLKDIS 4
#define MASK_CLOCK_FS 0x03
#define MASK_CLOCK_CLK 0x0c
#define BIT_SETUP_FSYNC 0
#define BIT_SETUP_BUF 1
#define BIT_SETUP_BU 2
#define BIT_SETUP_G0 3
#define BIT_SETUP_G1 4
#define BIT_SETUP_G2 5
#define BIT_SETUP_MD0 6
#define BIT_SETUP_MD1 7
#define MASK_SETUP_GAIN 0x38
#define MASK_SETUP_MODE 0xc0
static const spi_settings_t config = {
.endianness = SPI_BIG_ENDIAN,
.msb = true,
.minimal_pins = true,
.mode = SPI_MODE3,
.freq_divider = SPI_FREQ_DIV_500K
};
static uint8_t write(uint8_t cs_pin, uint8_t value)
{
spi_settings_t old;
spi_get_settings(BUS, &old);
spi_set_settings(BUS, &config);
gpio_write(cs_pin, false);
uint8_t res = spi_transfer_8(BUS, value);
//debug("byte wr: 0x%02x", value);
gpio_write(cs_pin, true);
spi_set_settings(BUS, &old);
return res;
}
inline static uint8_t read_byte(uint8_t cs_pin)
{
return write(cs_pin, 0);
}
static uint16_t read_word(uint8_t cs_pin)
{
spi_settings_t old;
spi_get_settings(BUS, &old);
spi_set_settings(BUS, &config);
gpio_write(cs_pin, false);
uint16_t res = spi_transfer_16(BUS, 0);
gpio_write(cs_pin, true);
spi_set_settings(BUS, &old);
return res;
}
static void prepare(uint8_t channel, uint8_t reg, bool read, uint8_t cs_pin, bool standby)
{
write(cs_pin,
(channel & MASK_COMM_CH) |
(read ? _BV(BIT_COMM_RW) : 0) |
((reg << BIT_COMM_RS0) & MASK_COMM_RS) |
(standby ? _BV(BIT_COMM_STBY) : 0)
);
}
int ad770x_init(const ad770x_params_t *params, uint8_t channel)
{
if (!spi_set_settings(BUS, &config))
{
debug("Cannot init SPI");
return -EIO;
}
if ((params->master_clock >= AD770X_MCLK_2_4576MHz && params->update_rate < AD770X_RATE_50)
|| (params->master_clock < AD770X_MCLK_2_4576MHz && params->update_rate > AD770X_RATE_200))
{
debug("Invalid update rate / master clock combination");
return -EINVAL;
}
gpio_enable(params->cs_pin, GPIO_OUTPUT);
gpio_write(params->cs_pin, true);
prepare(channel, REG_CLOCK, false, params->cs_pin, false);
write(params->cs_pin,
((params->master_clock << BIT_CLOCK_CLK) & MASK_CLOCK_CLK) |
(params->update_rate & MASK_CLOCK_FS)
);
ad770x_set_mode(params, channel, AD770X_MODE_CALIBRATION);
uint32_t start = sdk_system_get_time();
while (!ad770x_data_ready(params, channel))
if (timeout_expired(start, INIT_TIMEOUT))
{
debug("Timeout while calibration");
return -EIO;
}
return 0;
}
void ad770x_set_mode(const ad770x_params_t *params, uint8_t channel, ad770x_mode_t mode)
{
prepare(channel, REG_SETUP, false, params->cs_pin, false);
write(params->cs_pin,
((params->gain << BIT_SETUP_G0) & MASK_SETUP_GAIN) |
(params->bipolar ? 0 : _BV(BIT_SETUP_BU)) |
((mode << BIT_SETUP_MD0) & MASK_SETUP_MODE)
);
}
bool ad770x_data_ready(const ad770x_params_t *params, uint8_t channel)
{
prepare(channel, REG_COMM, true, params->cs_pin, false);
return !(read_byte(params->cs_pin) & _BV(BIT_COMM_DRDY));
}
uint16_t ad770x_raw_adc_value(const ad770x_params_t *params, uint8_t channel)
{
prepare(channel, REG_DATA, true, params->cs_pin, false);
return read_word(params->cs_pin);
}

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extras/ad770x/ad770x.h Normal file
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/**
* Driver for AD7705/AD7706 SPI ADC
*
* Part of esp-open-rtos
* Copyright (C) 2017 Ruslan V. Uss <unclerus@gmail.com>
* BSD Licensed as described in the file LICENSE
*/
#ifndef _EXTRAS_AD770X_H_
#define _EXTRAS_AD770X_H_
#include <stdint.h>
#include <stdbool.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* Input gain
*/
typedef enum
{
AD770X_GAIN_1 = 0,
AD770X_GAIN_2,
AD770X_GAIN_4,
AD770X_GAIN_8,
AD770X_GAIN_16,
AD770X_GAIN_32,
AD770X_GAIN_64,
AD770X_GAIN_128
} ad770x_gain_t;
/**
* Master clock frequency
*/
typedef enum
{
AD770X_MCLK_1MHz = 0, //!< 1 MHz
AD770X_MCLK_2MHz, //!< 2 MHz
AD770X_MCLK_2_4576MHz, //!< 2.4576 MHz
AD770X_MCLK_4_9152MHz, //!< 4.9152 MHz
} ad770x_master_clock_t;
/**
* Output update rate
*/
typedef enum
{
AD770X_RATE_20 = 0, //!< Output update rate is 20 Hz, -3 dB filter cutoff = 5.24 Hz, works with 1 or 2 MHz master clock
AD770X_RATE_25, //!< Output update rate is 25 Hz, -3 dB filter cutoff = 6.55 Hz, works with 1 or 2 MHz master clock
AD770X_RATE_100, //!< Output update rate is 100 Hz, -3 dB filter cutoff = 26.2 Hz, works with 1 or 2 MHz master clock
AD770X_RATE_200, //!< Output update rate is 200 Hz, -3 dB filter cutoff = 52.4 Hz, works with 1 or 2 MHz master clock
AD770X_RATE_50, //!< Output update rate is 50 Hz, -3 dB filter cutoff = 13.1 Hz, works with 2.4576 or 4.9152 MHz master clock
AD770X_RATE_60, //!< Output update rate is 60 Hz, -3 dB filter cutoff = 15.7 Hz, works with 2.4576 or 4.9152 MHz master clock
AD770X_RATE_250, //!< Output update rate is 250 Hz, -3 dB filter cutoff = 65.5 Hz, works with 2.4576 or 4.9152 MHz master clock
AD770X_RATE_500, //!< Output update rate is 500 Hz, -3 dB filter cutoff = 131 Hz, works with 2.4576 or 4.9152 MHz master clock
} ad770x_update_rate_t;
/**
* Device mode
*/
typedef enum
{
AD770X_MODE_NORMAL = 0,
AD770X_MODE_CALIBRATION,
AD770X_MODE_ZERO_CALIBRATION,
AD770X_MODE_FULL_CALIBRATION
} ad770x_mode_t;
/**
* Device descriptor
*/
typedef struct
{
uint8_t cs_pin; //!< GPIO pin for chip select
ad770x_master_clock_t master_clock; //!< Master clock frequency
bool bipolar; //!< Bipolar/Unipolar mode
ad770x_gain_t gain; //!< Input gain
ad770x_update_rate_t update_rate; //!< Output update rate
} ad770x_params_t;
/**
* Init device and setup channel params
* @param params Device descriptor pointer
* @param channel Input channel
* @return Non-zero when error occured
*/
int ad770x_init(const ad770x_params_t *params, uint8_t channel);
/**
* Set device mode (see datasheet)
* @param params Device descriptor pointer
* @param channel Input channel
* @param mode Device mode
*/
void ad770x_set_mode(const ad770x_params_t *params, uint8_t channel, ad770x_mode_t mode);
/**
* Get conversion status
* @param params Device descriptor pointer
* @param channel Input channel
* @return true when data is ready
*/
bool ad770x_data_ready(const ad770x_params_t *params, uint8_t channel);
/**
* Get converted ADC value
* @param params Device descriptor pointer
* @param channel Input channel
* @return Raw ADC value
*/
uint16_t ad770x_raw_adc_value(const ad770x_params_t *params, uint8_t channel);
#ifdef __cplusplus
}
#endif
#endif /* _EXTRAS_AD770X_H_ */

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extras/ad770x/component.mk Normal file
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# Component makefile for extras/ad770x (AD7705/AD7706 driver)
# expected anyone using ADC driver includes it as 'ad770x/ad770x.h'
INC_DIRS += $(ad770x_ROOT)..
# args for passing into compile rule generation
ad770x_SRC_DIR = $(ad770x_ROOT)
$(eval $(call component_compile_rules,ad770x))