The following describes ADC code implementation in the Sensor Controller Studio.

Start with configuring the needed data structures and task resources:

Data structures:

• cfg
  • resolution = 8
• output
  • value
• state
  • isLarger
  • nextVal

Task resources:

• Analog Pins
  • PIN_ANALOG
• COMPA
• Reference DAC
• RTC-Based Execution Scheduling
• Delay Insertion

C Code

Initialization Code:

//Select SAR ADC input pin compaSelectGpioInput(AUXIO_A_PIN_ANALOG); fwScheduleTask(1);

Execution Code:

//Enable comparator compaEnable(COMPA_PWRMODE_ANY); 

state.nextVal = 0x0080; // 1/2 VDD 

output.value = 0; //Set the reference DAC output to 1/2 VDD refdacStartOutputOnCompaRef(state.nextVal); refdacEnable(REFDAC_PWRMODE_ANY,REFDAC_REF_VDDS); 

U16 currBit = cfg.resolution; 
U16 step = 64; 

while(currBit > 0){ //Update DAC value refdacChangeOutputValue(state.nextVal); //Wait for DAC to stabilize... 
//An additional slight delay for DAC and comparator to stabilize... 
refdacWaitForStableOutput(); 

fwDelayUs(10); //Read comparator output compaGetOutput(state.isLarger); if(state.isLarger == 1){ 
state.nextVal += step; //Increase DAC value for next iteration 
}
else{ 
state.nextVal -= step; //Decrease DAC value for next iteration 
} 

step >>= 1; //Divide step by 2 
currBit -= 1; 

//Update output value 
output.value |= (state.isLarger << currBit); 
} 
refdacStopOutput(); 

compaSelectIntRef(COMPA_REF_VSS); //Disable peripherals 
refdacDisable(); 
compaDisable(); 
fwScheduleTask(1);

Termination Code:

//Disable peripherals 
refdacDisable(); 
compaDisable();