Hi, I'm looking at the AFE4403 EVM's source code (FW_SRCV2.3_Release).
/* Variables to modify depending on the application */
const unsigned char ILED1_CURR_MAX_mA = 45; // LED1 max current reqd. for application
const unsigned char ILED1_CURR_MIN_mA = 5; // LED1 min current reqd. for application
const unsigned char ILED2_CURR_MAX_mA = 45; // LED2 max current reqd. for application
const unsigned char ILED2_CURR_MIN_mA = 5; // LED2 min current reqd. for application
const unsigned char LOW_THR_PERCENT = 10; // Low Threshold Percent
const unsigned char HIGH_THR_PERCENT = 90; // High Threshold percent
const unsigned char HYS_PERCENT = 3; // Hysteresis percent
const unsigned char TARGET_THR_PERCENT = 33; // Target Threshold percent
/* End of Variables to modify depending on the application */
calibRoutineParams calibParams;
void AFE44xx_PowerOn_Init(void){
Init_AFE44xx_DRDY_Interrupt();
AFE44xx_Default_Reg_Init();
}
VOID main (VOID){ // code for MSP430F5529
WDTCTL = WDTPW + WDTHOLD;
AFE44xx_PowerOn_Init();
// ...
while (1){
if (readDataFlag){
readDataFlag = 0;
AFE44xx_SPO2_Data_buf[0] = AFE44xx_Reg_Read(42); //read RED Data
AFE44xx_SPO2_Data_buf[1] = AFE44xx_Reg_Read(43); //read Ambient data
AFE44xx_SPO2_Data_buf[2] = AFE44xx_Reg_Read(44); //read IR Data
AFE44xx_SPO2_Data_buf[3] = AFE44xx_Reg_Read(45); //read Ambient Data
AFE44xx_SPO2_Data_buf[4] = AFE44xx_Reg_Read(46); //read RED - Ambient Data
AFE44xx_SPO2_Data_buf[5] = AFE44xx_Reg_Read(47); //read IR - Ambient Data
//P5OUT |= BIT0; //Turn on LED P5.0 (Green)
if (CALIBRATION_ENABLED == TRUE)
{
calibrationLED1(AFE44xx_SPO2_Data_buf[2]);
calibrationLED2(AFE44xx_SPO2_Data_buf[0]);
}
// ...
else if (wholeString[0] == CALIBRATION_CMD) // Calibration Code Command
{
if (wholeString[1] == CALIBRATION_TRUE)
{
CALIBRATION_ENABLED = TRUE;
AFE44xx_Default_Reg_Init();
calibParams.ILED1_CURR_MAX_mA = ILED1_CURR_MAX_mA; // LED1 max current
calibParams.ILED1_CURR_MIN_mA = ILED1_CURR_MIN_mA; // LED1 min current
calibParams.ILED2_CURR_MAX_mA = ILED2_CURR_MAX_mA; // LED2 max current
calibParams.ILED2_CURR_MIN_mA = ILED2_CURR_MIN_mA; // LED2 min current
calibParams.LOW_THR_PERCENT = LOW_THR_PERCENT; // Low Threshold Percent
calibParams.HIGH_THR_PERCENT = HIGH_THR_PERCENT; // High Threshold percent
calibParams.HYS_PERCENT = HYS_PERCENT; // Hysteresis percent
calibParams.TARGET_THR_PERCENT = TARGET_THR_PERCENT; // Target Threshold percent
initCalibrationRoutine(&calibParams);
}
else if (wholeString[1] == CALIBRATION_FALSE)
{
CALIBRATION_ENABLED = FALSE;
}
}
// ...
}
void calibrationLED1(unsigned long LED1data)
{
// Variable declaration
static unsigned int LED1_waitTimeCount = 0;
static unsigned int LED1_blockSizeCount = 0;
static unsigned int LED1_freezeTimeCount = 0;
static unsigned long LED1_Meas_DC = 0;
static unsigned long LED1_Meas_DC_Est = 0;
static unsigned long ILED1Code;
unsigned long LED1InterimCode;
// LED1 Calibration State machine
switch (LED1CalibrationState){
// ...
}
How does this LED calibration State machine work for LED1 (IR LED) and LED2 (Red LED)?
Also, does each calibration algorithm works the same? I was curious whether there are some common parts of the both "calibrationLED1" and "calibrationLED2" function.
Lastly, how did those min/max/threshold/hysteresis values calculated?
