library for AMS ENS210 temperature and humidity sensor
Dependents: rIoTwear-temp-humid
AMS_ENS210.cpp
- Committer:
- UHSLMarcus
- Date:
- 2017-01-24
- Revision:
- 6:475b764b720d
- Parent:
- 5:22b8ef3a65e1
- Child:
- 7:d61772b5cd3b
File content as of revision 6:475b764b720d:
#include "AMS_ENS210.h" AMS_ENS210::AMS_ENS210(I2C * i2c) : _temp_mode(CONFIG_TEMP_OP_MODE), _humid_mode(CONFIG_HUMID_OP_MODE), _power_mode(CONFIG_POWER_MODE), _reset(0), temp_reading(0), humid_reading(0) { _i2c = i2c; } AMS_ENS210::AMS_ENS210(I2C * i2c, bool temp_single_shot, bool humid_single_shot) : _temp_mode(temp_single_shot), _humid_mode(humid_single_shot), _power_mode(CONFIG_POWER_MODE), _reset(0), temp_reading(0), humid_reading(0) { _i2c = i2c; } AMS_ENS210::AMS_ENS210(I2C * i2c, bool temp_single_shot, bool humid_single_shot, bool low_power) : _temp_mode(temp_single_shot), _humid_mode(humid_single_shot), _power_mode(low_power), _reset(0), temp_reading(0), humid_reading(0) { _i2c = i2c; } AMS_ENS210::~AMS_ENS210() {} bool AMS_ENS210::init() { return write_config(); } bool AMS_ENS210::reset() { _reset = true; bool success = write_config(true, false); _reset = false; return success; } bool AMS_ENS210::low_power_mode(bool low_power) { _power_mode = low_power; return write_config(true, false); } bool AMS_ENS210::low_power_mode() { return read_config(true, false)[0] & 1; // just mask bit 0 } bool AMS_ENS210::is_active() { char output[1]; i2c_read(SYS_STATUS, output, 1); return output[0] & 1; } bool AMS_ENS210::temp_continuous_mode(bool continuous) { _temp_mode = continuous; return write_config(false, true); } bool AMS_ENS210::temp_continuous_mode() { return read_config(false, true)[0] & 1; // just mask bit 0 } bool AMS_ENS210::humid_continuous_mode(bool continuous) { _humid_mode = continuous; return write_config(false, true); } bool AMS_ENS210::humid_continuous_mode() { return (read_config(false, true)[0] >> 1) & 1; // shift bit 1 and mask } void AMS_ENS210::i2c_interface(I2C * i2c) { _i2c = i2c; } I2C* AMS_ENS210::i2c_interface() { return _i2c; } bool AMS_ENS210::start(bool temp, bool humid) { char cmd[1] = {0 | temp | (humid << 1)}; return i2c_write(SENS_START, cmd, 1) == 1; //_i2c->write(ENS210_SLAVE_ADDR, cmd, 2) == 2; } bool AMS_ENS210::stop(bool temp, bool humid) { char cmd[1] = {0 | temp | (humid << 1)}; return i2c_write(SENS_STOP, cmd, 1) == 1; //_i2c->write(ENS210_SLAVE_ADDR, cmd, 2) == 2; } bool AMS_ENS210::temp_is_measuring() { char output[1]; i2c_read(SENS_STATUS, output, 1); return output[0] & 1; } bool AMS_ENS210::humid_is_measuring() { char output[1]; i2c_read(SENS_STATUS, output, 1); return output[0] >> 1 & 1; } bool AMS_ENS210::temp_has_data() { char output[3]; i2c_read(SENS_TEMP, output, 3); // do crc7 // Store read data to avoid reading from I2C again temp_reading = 0 | output[0] | (output[1] << 8); // bytes 1 and 2 make the 16 bit data bool valid = output[2] & 1; // bit 0 of byte 3 is the valid flag if (!valid) { if (!temp_continuous_mode()) { // when in single shot mode make sure sensor has started if (!temp_is_measuring()) start(true, false); // set start bit if sensor is idle } } return valid; } bool AMS_ENS210::humid_has_data() { char output[3]; i2c_read(SENS_HUMID, output, 3); // do crc7 // Store read data to avoid reading from I2C again humid_reading = 0 | output[0] | (output[1] << 8); // bytes 1 and 2 make the 16 bit data bool valid = output[2] & 1; // bit 0 of byte 3 is the valid flag if (!valid) { if (!humid_continuous_mode()) { // when in single shot mode make sure sensor has started first if (!humid_is_measuring()) start(false, true); // set start bit if sensor is idle } } return valid; } uint16_t AMS_ENS210::temp_read() { uint16_t reading = 0; if (!temp_continuous_mode()) { // when in single shot mode, data is read and saved in temp_has_data() reading = temp_reading; } else { char output[3]; i2c_read(SENS_TEMP, output, 3); // do crc7 if (output[2] & 1) // bit 0 of byte 3 is the valid flag reading = 0 | output[0] | (output[1] << 8); // bytes 1 and 2 make the 16 bit data } return reading; } uint16_t AMS_ENS210::humid_read() { uint16_t reading = 0; if (!humid_continuous_mode()) { // when in single shot mode, data is read and saved in humid_has_data() reading = humid_reading; } else { char output[3]; i2c_read(SENS_HUMID, output, 3); // do crc7 if (output[2] & 1) // bit 0 of byte 3 is the valid flag reading = 0 | output[0] | (output[1] << 8); // bytes 1 and 2 make the 16 bit data } return reading; } /*** Private ***/ bool AMS_ENS210::write_config(bool system, bool sensor) { int w_bytes = 0; char cmd[1]; if (system) { cmd[0] = 0 | _power_mode | _reset << 7; // bit 0 of SYS_CTRL is power mode, bit 7 is reset w_bytes += i2c_write(SYS_CONFIG, cmd, 1); //_i2c->write(ENS210_ENS210_ENS210_ENS210_ENS210_ENS210_ENS210_SLAVE_ADDR, cmd, 2); } if (sensor) { cmd[0] = 0 | _temp_mode | (_humid_mode << 1); // bit 0 is temp mode, bit 1 is humid mode w_bytes += i2c_write(SENS_OP_MODE, cmd, 1); //_i2c->write(ENS210_ENS210_ENS210_ENS210_ENS210_ENS210_ENS210_SLAVE_ADDR, cmd, 2); } return w_bytes == (system + sensor); } const char *AMS_ENS210::read_config(bool system, bool sensor) { // todo, maybe throw excpetion if i2c read fails? static char output[2] = {0, 0}; if (system) i2c_read(SYS_CONFIG, output, 1); if (sensor) i2c_read(SENS_OP_MODE, output+system, 1); return output; } int AMS_ENS210::i2c_read(char reg_addr, char* output, int len) { int read_count = 0; _i2c->start(); // send start condition for write if(_i2c->write(ENS210_SLAVE_ADDR_W) == 1) { // write slave address with write bit if(_i2c->write(reg_addr) == 1) { // write register address _i2c->start(); // send another start condition for read if(_i2c->write(ENS210_SLAVE_ADDR_R) == 1) { // write slave address with read bit for (int i = 0; i < len; i++) { // read len bytes output[i] = _i2c->read(i < len-1 ? 1 : 0); // ack all reads aside from the final one (i == len-1) read_count++; } } } } _i2c->stop(); // send stop condition return read_count; } int AMS_ENS210::i2c_write(char reg_addr, char* input, int len) { int write_count = 0; _i2c->start(); // send start condition for write if(_i2c->write(ENS210_SLAVE_ADDR_W) == 1) { // write slave address if(_i2c->write(reg_addr) == 1) { // write register address for (int i = 0; i < len; i++) { // write len bytes if(_i2c->write(input[i]) == 1) write_count++; // write each byte, if successful increment count } } } _i2c->stop(); // send stop condition return write_count; }