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AP_ADC: added ADS1115 support

This commit is contained in:
Staroselskii Georgii 2014-11-26 15:01:29 +03:00 committed by Andrew Tridgell
parent 195aa5fc6b
commit b5aef01f72
3 changed files with 292 additions and 0 deletions
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1
libraries/AP_ADC/AP_ADC.h
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@ -57,6 +57,7 @@ private:
};
#include "AP_ADC_ADS7844.h"
#include "AP_ADC_ADS1115.h"
#include "AP_ADC_HIL.h"
#endif

245
libraries/AP_ADC/AP_ADC_ADS1115.cpp Normal file
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@ -0,0 +1,245 @@
#include <AP_HAL.h>
#include "AP_ADC_ADS1115.h"
#define ADS1115_ADDRESS_ADDR_GND 0x48 // address pin low (GND)
#define ADS1115_ADDRESS_ADDR_VDD 0x49 // address pin high (VCC)
#define ADS1115_ADDRESS_ADDR_SDA 0x4A // address pin tied to SDA pin
#define ADS1115_ADDRESS_ADDR_SCL 0x4B // address pin tied to SCL pin
#define ADS1115_DEFAULT_ADDRESS ADS1115_ADDRESS_ADDR_GND
#define ADS1115_RA_CONVERSION 0x00
#define ADS1115_RA_CONFIG 0x01
#define ADS1115_RA_LO_THRESH 0x02
#define ADS1115_RA_HI_THRESH 0x03
#define ADS1115_OS_SHIFT 15
#define ADS1115_OS_INACTIVE 0x00 << ADS1115_OS_SHIFT
#define ADS1115_OS_ACTIVE 0x01 << ADS1115_OS_SHIFT
#define ADS1115_MUX_SHIFT 12
#define ADS1115_MUX_P0_N1 0x00 << ADS1115_MUX_SHIFT /* default */
#define ADS1115_MUX_P0_N3 0x01 << ADS1115_MUX_SHIFT
#define ADS1115_MUX_P1_N3 0x02 << ADS1115_MUX_SHIFT
#define ADS1115_MUX_P2_N3 0x03 << ADS1115_MUX_SHIFT
#define ADS1115_MUX_P0_NG 0x04 << ADS1115_MUX_SHIFT
#define ADS1115_MUX_P1_NG 0x05 << ADS1115_MUX_SHIFT
#define ADS1115_MUX_P2_NG 0x06 << ADS1115_MUX_SHIFT
#define ADS1115_MUX_P3_NG 0x07 << ADS1115_MUX_SHIFT
#define ADS1115_PGA_SHIFT 9
#define ADS1115_PGA_6P144 0x00 << ADS1115_PGA_SHIFT
#define ADS1115_PGA_4P096 0x01 << ADS1115_PGA_SHIFT
#define ADS1115_PGA_2P048 0x02 << ADS1115_PGA_SHIFT // default
#define ADS1115_PGA_1P024 0x03 << ADS1115_PGA_SHIFT
#define ADS1115_PGA_0P512 0x04 << ADS1115_PGA_SHIFT
#define ADS1115_PGA_0P256 0x05 << ADS1115_PGA_SHIFT
#define ADS1115_PGA_0P256B 0x06 << ADS1115_PGA_SHIFT
#define ADS1115_PGA_0P256C 0x07 << ADS1115_PGA_SHIFT
#define ADS1115_MV_6P144 0.187500
#define ADS1115_MV_4P096 0.125000
#define ADS1115_MV_2P048 0.062500 // default
#define ADS1115_MV_1P024 0.031250
#define ADS1115_MV_0P512 0.015625
#define ADS1115_MV_0P256 0.007813
#define ADS1115_MV_0P256B 0.007813
#define ADS1115_MV_0P256C 0.007813
#define ADS1115_MODE_SHIFT 8
#define ADS1115_MODE_CONTINUOUS 0x00 << ADS1115_MODE_SHIFT
#define ADS1115_MODE_SINGLESHOT 0x01 << ADS1115_MODE_SHIFT // default
#define ADS1115_RATE_SHIFT 5
#define ADS1115_RATE_8 0x00 << ADS1115_RATE_SHIFT
#define ADS1115_RATE_16 0x01 << ADS1115_RATE_SHIFT
#define ADS1115_RATE_32 0x02 << ADS1115_RATE_SHIFT
#define ADS1115_RATE_64 0x03 << ADS1115_RATE_SHIFT
#define ADS1115_RATE_128 0x04 << ADS1115_RATE_SHIFT // default
#define ADS1115_RATE_250 0x05 << ADS1115_RATE_SHIFT
#define ADS1115_RATE_475 0x06 << ADS1115_RATE_SHIFT
#define ADS1115_RATE_860 0x07 << ADS1115_RATE_SHIFT
#define ADS1115_COMP_MODE_SHIFT 4
#define ADS1115_COMP_MODE_HYSTERESIS 0x00 << ADS1115_COMP_MODE_SHIFT // default
#define ADS1115_COMP_MODE_WINDOW 0x01 << ADS1115_COMP_MODE_SHIFT
#define ADS1115_COMP_POL_SHIFT 3
#define ADS1115_COMP_POL_ACTIVE_LOW 0x00 << ADS1115_COMP_POL_SHIFT // default
#define ADS1115_COMP_POL_ACTIVE_HIGH 0x01 << ADS1115_COMP_POL_SHIFT
#define ADS1115_COMP_LAT_SHIFT 2
#define ADS1115_COMP_LAT_NON_LATCHING 0x00 << ADS1115_COMP_LAT_SHIFT // default
#define ADS1115_COMP_LAT_LATCHING 0x01 << ADS1115_COMP_LAT_SHIFT
#define ADS1115_COMP_QUE_SHIFT 0
#define ADS1115_COMP_QUE_ASSERT1 0x00 << ADS1115_COMP_SHIFT
#define ADS1115_COMP_QUE_ASSERT2 0x01 << ADS1115_COMP_SHIFT
#define ADS1115_COMP_QUE_ASSERT4 0x02 << ADS1115_COMP_SHIFT
#define ADS1115_COMP_QUE_DISABLE 0x03 // default
#define ADS1115_DEBUG 0
#if ADS1115_DEBUG
#include <cstdio>
#define debug(fmt, args ...) do {hal.console->printf("%s:%d: " fmt "\n", __FUNCTION__, __LINE__, ## args); } while(0)
#define error(fmt, args ...) do {fprintf(stderr,"%s:%d: " fmt "\n", __FUNCTION__, __LINE__, ## args); } while(0)
#else
#define debug(fmt, args ...)
#define error(fmt, args ...)
#endif
extern const AP_HAL::HAL& hal;
#define ADS1115_CHANNELS_COUNT 6
const uint8_t AP_ADC_ADS1115::_channels_number = ADS1115_CHANNELS_COUNT;
/* Only two differential channels used */
static const uint16_t mux_table[ADS1115_CHANNELS_COUNT] =
{
ADS1115_MUX_P1_N3,
ADS1115_MUX_P2_N3,
ADS1115_MUX_P0_NG,
ADS1115_MUX_P1_NG,
ADS1115_MUX_P2_NG,
ADS1115_MUX_P3_NG
};
AP_ADC_ADS1115::AP_ADC_ADS1115():
_i2c_sem(NULL),
_channel_to_read(0)
{
_samples = new adc_report_s[_channels_number];
}
bool AP_ADC_ADS1115::init()
{
hal.scheduler->suspend_timer_procs();
_gain = ADS1115_PGA_4P096;
_i2c_sem = hal.i2c->get_semaphore();
hal.scheduler->register_timer_process(AP_HAL_MEMBERPROC(&AP_ADC_ADS1115::_update));
hal.scheduler->resume_timer_procs();
return true;
}
bool AP_ADC_ADS1115::_start_conversion(uint8_t channel)
{
union {
uint16_t w;
uint8_t b[2];
} config;
config.w = ADS1115_OS_ACTIVE | _gain | mux_table[channel] |
ADS1115_MODE_SINGLESHOT | ADS1115_COMP_QUE_DISABLE | ADS1115_RATE_250;
config.w = config.b[0] << 8 | config.b[1];
if (hal.i2c->writeRegisters((uint8_t)ADS1115_ADDRESS_ADDR_GND, ADS1115_RA_CONFIG, 2, (uint8_t *) &config) != 0) {
return false;
}
return true;
}
size_t AP_ADC_ADS1115::read(adc_report_s *report, size_t length) const
{
for (size_t i = 0; i < length; i++) {
report[i].data = _samples[i].data;
report[i].id = _samples[i].id;
}
return length;
}
float AP_ADC_ADS1115::_convert_register_data_to_mv(int16_t word) const
{
float pga;
switch (_gain) {
case ADS1115_PGA_6P144:
pga = ADS1115_MV_6P144;
break;
case ADS1115_PGA_4P096:
pga = ADS1115_MV_4P096;
break;
case ADS1115_PGA_2P048:
pga = ADS1115_MV_2P048;
break;
case ADS1115_PGA_1P024:
pga = ADS1115_MV_1P024;
break;
case ADS1115_PGA_0P512:
pga = ADS1115_MV_0P512;
break;
case ADS1115_PGA_0P256:
pga = ADS1115_MV_0P256;
break;
case ADS1115_PGA_0P256B:
pga = ADS1115_MV_0P256B;
break;
case ADS1115_PGA_0P256C:
pga = ADS1115_MV_0P256C;
break;
default:
pga = 0.0f;
hal.console->printf("Wrong gain");
hal.scheduler->panic(PSTR("ADS1115: wrong gain selected"));
break;
}
return (float) word * pga;
}
void AP_ADC_ADS1115::_update()
{
/* TODO: make update rate configurable */
if (hal.scheduler->micros() - _last_update_timestamp < 100000) {
return;
}
union {
uint8_t b[2];
int16_t w;
} word, config;
if (!_i2c_sem->take_nonblocking()) {
return;
}
if ( hal.i2c->readRegisters(ADS1115_ADDRESS_ADDR_GND, ADS1115_RA_CONFIG, 2, config.b) != 0 ) {
error("i2c->readRegisters failed in ADS1115");
_i2c_sem->give();
return;
}
/* check rdy bit */
if ((config.b[1] & 0x80) != 0x80 ) {
_i2c_sem->give();
return;
}
if ( hal.i2c->readRegisters(ADS1115_ADDRESS_ADDR_GND, ADS1115_RA_CONVERSION, 2, word.b) != 0 ) {
_i2c_sem->give();
return;
}
word.w = word.b[0] << 8 | word.b[1]; /* Exchange MSB and LSB */
float sample = _convert_register_data_to_mv(word.w);
_samples[_channel_to_read].data = sample;
_samples[_channel_to_read].id = _channel_to_read;
/* select next channel */
_channel_to_read = (_channel_to_read + 1) % _channels_number;
_start_conversion(_channel_to_read);
_i2c_sem->give();
_last_update_timestamp = hal.scheduler->micros();
}

46
libraries/AP_ADC/AP_ADC_ADS1115.h Normal file
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@ -0,0 +1,46 @@
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#ifndef __AP_ADC_ADS1115_H__
#define __AP_ADC_ADS1115_H__
#include <inttypes.h>
#include "AP_ADC.h"
#include <AP_HAL.h>
struct adc_report_s
{
uint8_t id;
float data;
};
class AP_ADC_ADS1115
{
public:
AP_ADC_ADS1115();
bool init();
size_t read(adc_report_s *report, size_t length) const;
uint8_t get_channels_number() const
{
return _channels_number;
}
private:
static const uint8_t _channels_number;
uint32_t _last_update_timestamp;
uint16_t _gain;
int _channel_to_read;
adc_report_s *_samples;
AP_HAL::Semaphore* _i2c_sem;
void _update();
bool _start_conversion(uint8_t channel);
float _convert_register_data_to_mv(int16_t word) const;
};
#endif