Hi TI team,
I am trying to program the FDC2212 sensor registers using the Teensy board and I am having difficulty with using I2C protocol to read/write from registers. I believe that the register address is 8bits and each register contains 16bits. In my debugging, when I attempt to read from registers after writing, I keep getting 1111111111111111 as the output. I have tried exploring various solutions (including the code Josue kindly provided in FDC2214 in the Arduino environment - Sensors forum - Sensors - TI E2E support forums) but I am still having this issue. Any advice or feedback is appreciated. My code is below:
#define CDC_I2C_ADDR 0x2B
#define SDA1 17
#define SCL1 16
uint16_t I2CReadRegister(uint8_t registerAddr){
Wire.beginTransmission(CDC_I2C_ADDR);
Wire.write(registerAddr);
Wire.endTransmission();
Wire.requestFrom(CDC_I2C_ADDR, 2); // This register is 16 bits = 2 bytes long
// Read into a 2-byte buffer
byte buf[2];
uint8_t b1 = Wire.read();
uint8_t b2 = Wire.read();
uint16_t val = (b1 << 8) | b2;
return val;
}
void I2CwriteRegister(uint8_t registerAddr, uint8_t val, uint8_t val2) {
byte writeArray[2];
writeArray[0] = val;
writeArray[1] = val2;
Wire.beginTransmission(CDC_I2C_ADDR);
Wire.write(registerAddr);
Wire.write(writeArray, 2);
Wire.endTransmission();
}
void setup() {
Wire.setSDA(SDA1);
Wire.setSCL(SCL1);
Wire.begin();
Wire.setClock(100000); // speed of I2C interface, max value 400kbits
Serial.begin(9600); // Default to 9600 baud rate for COM port
initCDC();
}
void initCDC() {
// Setting clock dividers for Ch0 and Ch1
// Affected fields: CHx_FIN_SEL, CHx_FREF_DIVIDER
// CHx_FIN_SEL: b01 divide by 1. Choose for sensor frequencies between 0.01MHz and 8.75MHz (expected ~5-6 MHz)
// CHx_FREF_DIVIDER: Sets the divider for channel x reference. Use this to scale the maximum conversion frequency.
I2CwriteRegister(CLOCK_DIVIDERS_CH0, 0b00010000, 0b00000001); // finalized b0001_00_0000000001
//I2CwriteRegister(CLOCK_DIVIDERS_CH1, 0b00010000, 0b00000001); // finalized b0001_00_0000000001
Serial.println(I2CReadRegister(CLOCK_DIVIDERS_CH0), BIN);
//I2CReadRegister(CLOCK_DIVIDERS_CH1);
// Sensor drive current: ensure oscillation amplitude is between 1.2V and 1.8V
// Affected fields: CHx_IDRIVE
// CHx_IDRIVE: defines the Drive Current used during the settling + conversion time of the channel x sensor clock. Set such that 1.2V <= sensor oscillation amplitude (pk) <= 1.8V
// Notes: Measure Vpk with an oscilloscope and adjust the IDRIVE value manually
//I2CwriteRegister(DRIVE_CURRENT_CH0, 0b00000000, 0b00000000); // not finalized: start with 0.108mA and measure the voltage then retry. b11000_00000000000
//I2CwriteRegister(DRIVE_CURRENT_CH1, 0b00000000, 0b00000000); // not finalized b00111_00000000000 set to 0.044mA, can take it down as long as sensor activates
//I2CReadRegister(DRIVE_CURRENT_CH0);
//I2CReadRegister(DRIVE_CURRENT_CH1);
// Sensor activation time: The amount of settling time required for the sensor oscillation to stablize
// Set to a value that is long enough to allow stable oscillation.
// The FDC will use this settling time to allow the LC sensor to stabilize before initiation of a conversion on Channel 0.
// If the amplitude has not settled prior to the conversion start, an Amplitude warning will be generated if reporting of this type of warning is enabled.
// Affected fields: CHx_SETTLECOUNT
//I2CwriteRegister(SETTLECOUNT_CH0, 0b00000000, 0b11111111); // not finalized: set to 100 clk cycles b0000000001100100
//I2CwriteRegister(SETTLECOUNT_CH1, 0b00000000, 0b00000111); // finalized to minimum allowed value (dummy channel) b0000000000000100
//I2CReadRegister(SETTLECOUNT_CH0);
//I2CReadRegister(SETTLECOUNT_CH1);
// The number of reference clock cycles used to measure the sensor frequency. Higher the number, the longer the conversion time.
// Affected fields: CHx_RCOUNT
//I2CwriteRegister(RCOUNT_CH0, 0b00100000, 0b00000000); // not finalized: start with ENOB = 13bits and then readjust as needed b0010000000000000
//I2CwriteRegister(RCOUNT_CH1, 0b00000000, 0b00001001); // finalized to minimum allowed value (dummy channel) b0000000000001001
//I2CReadRegister(RCOUNT_CH0);
//I2CReadRegister(RCOUNT_CH1);
// Enable interrupts to report status and error conditions (also referred to as ERROR_CONFIG in datasheet)
// Affected fields: ERROR_CONFIG
// WD_ERR2OUT: b1 Report Watchdog Timeout errors in DATA_CHx.CHx_ERR_WD register field
// AH_WARN2OUT: b1 Report Amplitude High warnings in the DATA_CHx.CHx_ERR_AW register field
// WD_ERR2INT, DRDY_2INT: General Watchdog Timeout error and Data Ready Flag set to off since we want specific flags for CH0 only.
// Only care about CH0 and ignore the flags in CH1 (dummy channel)
//I2CwriteRegister(STATUS_CONFIG, 0b00110000, 0b00000000); // not finalized: should toggle between AH_WARN2OUT and AL_WARN2OUT for amplitude errors. b00_1_1_0_00000_0_0000_0
//I2CReadRegister(STATUS_CONFIG);
// Channel Multiplexing Configuration
// Affected Fields: AUTOSCAN_EN, RR_SEQUENCE, DEGLITCH
// AUTOSCAN_EN, RR_SEQUENCE: b00 Enable multi-channel operation, scanning on Ch0, Ch1
// DEGLITCH: b101 set input deglitch filter bandwidth to 10MHz, the lowest setting that exceeds the oscillation tank oscillation frequency (~5-6 MHz). b1_00_0001000001_101
//I2CwriteRegister(MUX_CONFIG, 0b10000010, 0b00001101);
//I2CReadRegister(MUX_CONFIG);
// Device Configuration (this register write must occur last because device configuration is not permitted while the FDC is in active mode).
// Affected Fields: ACTIVE_CHAN, SLEEP_MODE_EN, SENSOR_ACTIVATE_SEL, REF_CLK_SRC, INTB_DIS, HIGH_CURRENT_DRV
// ACTIVE_CHAN: inconsequential since we are running in multichannel operation
// SLEEP_MODE_EN: b0 exit Sleep mode to begin conversion process
// SENSOR_ACTIVATE_SEL: b0 set to Full Current Activation Mode - the FDC will drive maximum sensor current for a shorter sensor activation time.
// REF_CLK_SRC: b1 use the external clock frequency 40MHz
// INTB_DIS: the INTB pin will be asserted when status register updates.
// HIGH_CURRENT_DRV: b0 The FDC will drive all channels with normal sensor current (1.5mA max).
//I2CwriteRegister(CONFIG, 0b00010110, 0b00000001); // not finalized: toggle SENSOR_ACTIVATE_SEL if Vpk is too high >1.8V b00_0_1_0_1_1_0_0_0_000001
//I2CReadRegister(CONFIG);
Serial.println("Done.");
}
Many thanks,
Shane
