秋月電子、スイッチサイエンス、Aliexpressなどで販売されているADS1015ブレークアウト基板を使ってみた。
ADCはAVR内蔵のものしか使ってみたことがないがADS1015はかなり安定しているように見える。これはいいかも。基準電源を内蔵しているので部品点数も少なくて済む。但し、I2Cなので高速サンプリングは期待できないが．．．って、それは気にしないことにして、いつものようにライブラリを作ってみた。ADS1015とADS1115の両方に対応してみた。
【続編】
ADS1015/ADS1115ライブラリを改良してみた。
【サンプル・スケッチ】
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#include <Wire.h> #include "ADS1015.h" ADS1X15<> adc; void setup() { Serial.begin(115200); while (!Serial) continue; Wire.begin(); Wire.setClock(400000); // 400KHz adc.mux(ADS1X15_MUX_AIN0_GND); adc.pga(ADS1X15_PGA_6144V); adc.begin(); } void loop() { static int32_t next; switch (adc.handle()) { case ADS1X15_STATUS_NO_DEVICE: if (millis() - next >= 1000) { next += 1000; Serial.println("no device."); } break; case ADS1X15_STATUS_READY: if (millis() - next >= 1000) { next += 1000; Serial.print(adc.voltage()); Serial.println(" uV"); } break; default: break; } } |
【ライブラリ】
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/* * ADC Library for ADS1015 * * Sasapea's Lab: 2019-11-10 */ #ifndef __ADS1015_H #define __ADS1015_H #define ADS1015 #define ADS1X15_RESOLUSION 12 #define ADS1X15_DR_DEFAULT ADS1X15_DR_1600SPS typedef enum { ADS1X15_PGA_6144V, ADS1X15_PGA_4096V, ADS1X15_PGA_2048V, ADS1X15_PGA_1024V, ADS1X15_PGA_0512V, ADS1X15_PGA_0256V, ADS1X15_PGA_0128V, } ADS1X15_PGA; #define ADS1X15_REFERENCES \ { 6144000, 4096000, 2048000, 1024000, 512000, 256000, 128000 } typedef enum { ADS1X15_DR_128SPS, ADS1X15_DR_250SPS, ADS1X15_DR_490SPS, ADS1X15_DR_920SPS, ADS1X15_DR_1600SPS, ADS1X15_DR_2400SPS, ADS1X15_DR_3300SPS, } ADS1X15_DR; #define ADS1X15_CONVERSION_TIMES \ { 1000127 / 128, 1000249 / 250, 1000489 / 490, 1000919 / 920, \ 1001599 / 1600, 1002399 / 2400, 1003299 / 3300 } #include "ADS1X15.h" #endif |
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/* * ADC Library for ADS1115 * * Sasapea's Lab: 2019-11-10 */ #ifndef __ADS1115_H #define __ADS1115_H #define ADS1115 #define ADS1X15_RESOLUSION 16 #define ADS1X15_DR_DEFAULT ADS1X15_DR_128SPS typedef enum { ADS1X15_PGA_6144V, ADS1X15_PGA_4096V, ADS1X15_PGA_2048V, ADS1X15_PGA_1024V, ADS1X15_PGA_0512V, ADS1X15_PGA_0256V, } ADS1X15_PGA; #define ADS1X15_REFERENCES \ { 6144000, 4096000, 2048000, 1024000, 512000, 256000 } typedef enum { ADS1X15_DR_8SPS, ADS1X15_DR_16SPS, ADS1X15_DR_32SPS, ADS1X15_DR_64SPS, ADS1X15_DR_128SPS, ADS1X15_DR_250SPS, ADS1X15_DR_475SPS, ADS1X15_DR_860SPS, } ADS1X15_DR; #define ADS1X15_CONVERSION_TIMES \ { 1000007 / 8, 1000015 / 16, 1000031 / 32, 1000063 / 64, \ 1000127 / 128, 1000249 / 250, 1000474 / 475, 1000859 / 860 } #include "ADS1X15.h" #endif |
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/* * ADC Library for ADS1X15 * * Sasapea's Lab: 2019-11-10 */ #ifndef __ADS1X15_H #define __ADS1X15_H #include <stdint.h> #include <stdbool.h> #ifndef ARDUINO #define makeWord(h, l) (((uint16_t)h << 8) | (uint8_t)l) #endif #ifndef lowByte #define lowByte(w) (uint8_t)(w) #endif #ifndef highByte #define highByte(w) (uint8_t)((w) >> 8) #endif #define ADS1X15_DEVICE_ADDRESS 0x48 #define ADS1X15_RETRY_INTERVAL 1000000 typedef enum { ADS1X15_STATUS_NO_DEVICE, ADS1X15_STATUS_IDLE, ADS1X15_STATUS_BUSY, ADS1X15_STATUS_READY, } ADS1X15_STATUS; typedef enum { ADS1X15_REG_CONVERSION, ADS1X15_REG_CONFIG, ADS1X15_REG_LO_THRESH, ADS1X15_REG_HI_THRESH, } ADS1X15_REG; typedef enum { ADS1X15_OS_NONE, ADS1X15_OS_CONVERSION, } ADS1X15_OS; typedef enum { ADS1X15_MUX_AIN0_AIN1, ADS1X15_MUX_AIN0_AIN3, ADS1X15_MUX_AIN1_AIN3, ADS1X15_MUX_AIN2_AIN3, ADS1X15_MUX_AIN0_GND, ADS1X15_MUX_AIN1_GND, ADS1X15_MUX_AIN2_GND, ADS1X15_MUX_AIN3_GND, } ADS1X15_MUX; typedef enum { ADS1X15_MODE_CONTINUOUS, ADS1X15_MODE_POWER_DOWN, } ADS1X15_MODE; typedef enum { ADS1X15_COMP_MODE_TRADITIONAL, ADS1X15_COMP_MODE_WINDOW, } ADS1X15_COMP_MODE; typedef enum { ADS1X15_COMP_POL_ACTIVE_LOW, ADS1X15_COMP_POL_ACTIVE_HIGH, } ADS1X15_COMP_POL; typedef enum { ADS1X15_COMP_LAT_DISABLE, ADS1X15_COMP_LAT_ENABLE, } ADS1X15_COMP_LAT; typedef enum { ADS1X15_COMP_QUE_ONE, ADS1X15_COMP_QUE_TWO, ADS1X15_COMP_QUE_FOUR, ADS1X15_COMP_QUE_DISABLE, } ADS1X15_COMP_QUE; typedef union { struct { ADS1X15_COMP_QUE comp_que :2; ADS1X15_COMP_LAT comp_lat :1; ADS1X15_COMP_POL comp_pol :1; ADS1X15_COMP_MODE comp_mode:1; ADS1X15_DR dr :3; ADS1X15_MODE mode :1; ADS1X15_PGA pga :3; ADS1X15_MUX mux :3; ADS1X15_OS os :1; } reg; uint16_t val; } ADS1X15_CONFIG; template<typename WIRE = TwoWire, WIRE& WOBJ = Wire> class ADS1X15 { private: uint8_t _addr; int32_t _value; uint32_t _start; ADS1X15_CONFIG _config; ADS1X15_CONFIG _active; ADS1X15_STATUS _status; uint8_t write(ADS1X15_REG reg, uint16_t data) { WOBJ.beginTransmission(_addr); WOBJ.write(reg); WOBJ.write(highByte(data)); WOBJ.write(lowByte(data)); return WOBJ.endTransmission(); } uint8_t read(ADS1X15_REG reg, uint16_t *data) { WOBJ.beginTransmission(_addr); WOBJ.write(reg); uint8_t rv = WOBJ.endTransmission(false); if (rv == 0) { if (WOBJ.requestFrom(_addr, sizeof(*data)) == sizeof(*data)) { uint8_t high = WOBJ.read(); uint8_t low = WOBJ.read(); *data = makeWord(high, low); } else rv = 4; } return rv; } uint8_t start(void) { uint8_t rv = write(ADS1X15_REG_CONFIG, _config.val); if (rv == 0) _active = _config; return rv; } uint8_t fetch(void) { uint16_t val; uint8_t rv = read(ADS1X15_REG_CONVERSION, &val); if (rv == 0) { if (_active.reg.mux < ADS1X15_MUX_AIN0_GND) _value = (int16_t)val; else _value = val; } return rv; } void os(ADS1X15_OS value) { _config.reg.os = value; } void mode(ADS1X15_MODE value) { _config.reg.mode = value; } public: ADS1X15(uint8_t addr = ADS1X15_DEVICE_ADDRESS) : _addr(addr) , _value(0) , _start(0) , _status(ADS1X15_STATUS_NO_DEVICE) { const ADS1X15_CONFIG _DEFAULT = { ADS1X15_COMP_QUE_DISABLE, ADS1X15_COMP_LAT_DISABLE, ADS1X15_COMP_POL_ACTIVE_LOW, ADS1X15_COMP_MODE_TRADITIONAL, ADS1X15_DR_DEFAULT, ADS1X15_MODE_POWER_DOWN, ADS1X15_PGA_2048V, ADS1X15_MUX_AIN0_AIN1, ADS1X15_OS_CONVERSION, }; _config = _active = _DEFAULT; } void mux(ADS1X15_MUX value) { _config.reg.mux = value; } void pga(ADS1X15_PGA value) { _config.reg.pga = value; } void dr(ADS1X15_DR value) { _config.reg.dr = value; } void comp_mode(ADS1X15_COMP_MODE value) { _config.reg.comp_mode = value; } void comp_pol(ADS1X15_COMP_POL value) { _config.reg.comp_pol = value; } void comp_lat(ADS1X15_COMP_LAT value) { _config.reg.comp_lat = value; } void comp_que(ADS1X15_COMP_QUE value) { _config.reg.comp_que = value; } uint8_t resolution() { return ADS1X15_RESOLUSION; } uint32_t reference() { static const uint32_t REFERENCES[] = ADS1X15_REFERENCES; return REFERENCES[_active.reg.pga]; } int32_t measured_value() { return _value; } int32_t voltage(void) { return (int32_t)((double)measured_value() * reference() / 32768); } void begin() { _start = micros() - ADS1X15_RETRY_INTERVAL; } ADS1X15_STATUS handle(void) { static const uint32_t CONVERSION_TIMES[] = ADS1X15_CONVERSION_TIMES; switch (_status) { default: case ADS1X15_STATUS_NO_DEVICE: if (micros() - _start < ADS1X15_RETRY_INTERVAL) break; case ADS1X15_STATUS_IDLE: _status = (start() ? ADS1X15_STATUS_NO_DEVICE : ADS1X15_STATUS_BUSY); _start = micros(); break; case ADS1X15_STATUS_BUSY: if (micros() - _start < CONVERSION_TIMES[_active.reg.dr]) break; if (fetch() == 0) { _status = ADS1X15_STATUS_IDLE; return ADS1X15_STATUS_READY; } _start = micros(); _status = ADS1X15_STATUS_NO_DEVICE; break; } return _status; } }; #endif |