mirror of https://github.com/esphome/esphome.git
127 lines
3.2 KiB
C++
127 lines
3.2 KiB
C++
#include "ads1118.h"
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#include "esphome/core/log.h"
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namespace esphome {
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namespace ads1118 {
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static const char *const TAG = "ads1118";
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static const uint8_t ADS1118_DATA_RATE_860_SPS = 0b111;
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void ADS1118::setup() {
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ESP_LOGCONFIG(TAG, "Setting up ads1118");
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this->spi_setup();
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this->config_ = 0;
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// Setup multiplexer
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// 0bx000xxxxxxxxxxxx
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this->config_ |= ADS1118_MULTIPLEXER_P0_NG << 12;
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// Setup Gain
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// 0bxxxx000xxxxxxxxx
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this->config_ |= ADS1118_GAIN_6P144 << 9;
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// Set singleshot mode
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// 0bxxxxxxx1xxxxxxxx
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this->config_ |= 0b0000000100000000;
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// Set data rate - 860 samples per second (we're in singleshot mode)
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// 0bxxxxxxxx100xxxxx
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this->config_ |= ADS1118_DATA_RATE_860_SPS << 5;
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// Set temperature sensor mode - ADC
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// 0bxxxxxxxxxxx0xxxx
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this->config_ |= 0b0000000000000000;
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// Set DOUT pull up - enable
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// 0bxxxxxxxxxxxx0xxx
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this->config_ |= 0b0000000000001000;
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// NOP - must be 01
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// 0bxxxxxxxxxxxxx01x
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this->config_ |= 0b0000000000000010;
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// Not used - can be 0 or 1, lets be positive
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// 0bxxxxxxxxxxxxxxx1
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this->config_ |= 0b0000000000000001;
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}
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void ADS1118::dump_config() {
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ESP_LOGCONFIG(TAG, "ADS1118:");
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LOG_PIN(" CS Pin:", this->cs_);
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}
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float ADS1118::request_measurement(ADS1118Multiplexer multiplexer, ADS1118Gain gain, bool temperature_mode) {
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uint16_t temp_config = this->config_;
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// Multiplexer
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// 0bxBBBxxxxxxxxxxxx
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temp_config &= 0b1000111111111111;
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temp_config |= (multiplexer & 0b111) << 12;
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// Gain
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// 0bxxxxBBBxxxxxxxxx
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temp_config &= 0b1111000111111111;
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temp_config |= (gain & 0b111) << 9;
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if (temperature_mode) {
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// Set temperature sensor mode
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// 0bxxxxxxxxxxx1xxxx
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temp_config |= 0b0000000000010000;
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} else {
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// Set ADC mode
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// 0bxxxxxxxxxxx0xxxx
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temp_config &= 0b1111111111101111;
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}
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// Start conversion
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temp_config |= 0b1000000000000000;
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this->enable();
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this->write_byte16(temp_config);
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this->disable();
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// about 1.2 ms with 860 samples per second
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delay(2);
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this->enable();
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uint8_t adc_first_byte = this->read_byte();
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uint8_t adc_second_byte = this->read_byte();
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this->disable();
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uint16_t raw_conversion = encode_uint16(adc_first_byte, adc_second_byte);
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auto signed_conversion = static_cast<int16_t>(raw_conversion);
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if (temperature_mode) {
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return (signed_conversion >> 2) * 0.03125f;
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} else {
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float millivolts;
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float divider = 32768.0f;
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switch (gain) {
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case ADS1118_GAIN_6P144:
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millivolts = (signed_conversion * 6144) / divider;
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break;
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case ADS1118_GAIN_4P096:
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millivolts = (signed_conversion * 4096) / divider;
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break;
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case ADS1118_GAIN_2P048:
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millivolts = (signed_conversion * 2048) / divider;
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break;
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case ADS1118_GAIN_1P024:
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millivolts = (signed_conversion * 1024) / divider;
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break;
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case ADS1118_GAIN_0P512:
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millivolts = (signed_conversion * 512) / divider;
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break;
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case ADS1118_GAIN_0P256:
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millivolts = (signed_conversion * 256) / divider;
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break;
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default:
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millivolts = NAN;
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}
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return millivolts / 1e3f;
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}
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}
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} // namespace ads1118
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} // namespace esphome
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