TMS320 F28035 Experimenter Kit

Hello.

Have you downloaded ControlSUIT ?

If not, I strongly reccomend to do this. It contains LOTS of examples for LOTS of microcontrollers, for every peripheral device. Sure you'll find well commented ADC and PWM examples there ;)

Hello Disona,

I did and i tried changing an example from there but again I wasn't able to fully understand what to change in order to read the ADC pin.

Ok, I'll try to help.

Let's take this example: C:\ti\controlSUITE\device_support\f2803x\v130\DSP2803x_examples_ccsv5\adc_socsssssssssss

ADC channel is configured here:

AdcRegs.ADCCTL1.bit.INTPULSEPOS = 1; //ADCINT1 trips after AdcResults latch
AdcRegs.INTSEL1N2.bit.INT1E = 1; //Enabled ADCINT1
AdcRegs.INTSEL1N2.bit.INT1CONT = 0; //Disable ADCINT1 Continuous mode
AdcRegs.INTSEL1N2.bit.INT1SEL = 2; //setup EOC2 to trigger ADCINT1 to fire
AdcRegs.ADCSOC0CTL.bit.CHSEL = 4; //set SOC0 channel select to ADCINA4(dummy sample for rev0 errata workaround)
AdcRegs.ADCSOC1CTL.bit.CHSEL = 4; //set SOC1 channel select to ADCINA4
AdcRegs.ADCSOC2CTL.bit.CHSEL = 2; //set SOC2 channel select to ADCINA2
AdcRegs.ADCSOC0CTL.bit.TRIGSEL = 5; //set SOC0 start trigger on EPWM1A, due to round-robin SOC0 converts first then SOC1, then SOC2
AdcRegs.ADCSOC1CTL.bit.TRIGSEL = 5; //set SOC1 start trigger on EPWM1A, due to round-robin SOC0 converts first then SOC1, then SOC2
AdcRegs.ADCSOC2CTL.bit.TRIGSEL = 5; //set SOC2 start trigger on EPWM1A, due to round-robin SOC0 converts first then SOC1, then SOC2
AdcRegs.ADCSOC0CTL.bit.ACQPS = 6; //set SOC0 S/H Window to 7 ADC Clock Cycles, (6 ACQPS plus 1)
AdcRegs.ADCSOC1CTL.bit.ACQPS = 6; //set SOC1 S/H Window to 7 ADC Clock Cycles, (6 ACQPS plus 1)
AdcRegs.ADCSOC2CTL.bit.ACQPS = 6; //set SOC2 S/H Window to 7 ADC Clock Cycles, (6 ACQPS plus 1)

At first you should know, that ADC operates in terms of SOCs (start-of-conversion). SOC is some kind of parameter set, that holds three things: 1 channel to be converterd, sample-and-hold window for that conversion, and a trigger, that will start conversion. So you can configure 16 different conversion, and every of them may be started at any time, independent from each other.

In the code above 3 SOCs are configured. Let's skip first four lines (you can just copy them). The other 9 lines configure 3 SOCs. Let's take a look at one of them:

AdcRegs.ADCSOC2CTL.bit.CHSEL = 2; //set SOC2 channel select to ADCINA2
AdcRegs.ADCSOC2CTL.bit.TRIGSEL = 5;
AdcRegs.ADCSOC2CTL.bit.ACQPS = 6; //set SOC2 S/H Window to 7 ADC Clock Cycles, (6 ACQPS plus 1)

So, the first line actually selects ADC channel - what you cal a pin. It's written in ADC description, that CHSEL = 0 means chan. A0, CHSEL = 1 means chan. A1,
and so on to CHSEL = 7 - chan A7. Then, CHSEL = 8 means chan. B0, CHSEL = 9 means B1 and so on.

Next line is used to chose ADC start time. There are many options - you can start ADC conversion by software (set a special bit), you can start ADC conversion from a TIMER, and so on. Refer to ADC documentation. In this example TRIGSEL = 5 means that ADC conversion will start when EPWM1A timer will generate a Start-Of-Conversion signal. (You should configure EPWM1 to generate this signal).

The last register ACQPS selects Sample-and-Hold window. It can't be less then 6, and there's allways added "1". So ACQPS = 6 means, that your signal will be samples for 6+1=7 cycles. After that a conversion will start (about 10-15 cycles). After conversion finishes and result is ready you will get an interrupt (first four lines of ADC configuration set this).

Hope this will help.

Thank you very much for your help :)