F28335, ADC SOC triggered by CPU Timer

Pankaj Kadam

Other Parts Discussed in Thread: TMS320F28335

Hi all,

I am using the TMS320F28335 Delfino Experimental kit.

I want to use CPU Timer0 to trigger the SOC for ADC. I am using the ADC in Dual, simultaneous mode. The same program worked fine using PWM as SOC trigger but at this stage of my project, I am will be using all the 6 PWM as a result had to switch to CPU Timer0.

I tried the following commands to initialize SOC via software trigger but how do I assign the software trigger to be from CPU Timer0?

AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 1 ;
AdcRegs.ADCTRL2.bit.SOC_SEQ2=1;

AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 1;
AdcRegs.ADCTRL2.bit.INT_ENA_SEQ2 = 1;

AdcRegs.ADCTRL2.bit.INT_MOD_SEQ1=1;
AdcRegs.ADCTRL2.bit.INT_MOD_SEQ2=1;

Best Regards,

Pankaj

over 11 years ago

0 Pankaj Kadam over 11 years ago

Intellectual 480 points

To my previous setting I also have the ADCINT set to the CPU Timer0 ISR

EALLOW;

PieVectTable.TINT0 = &cpu_timer0_isr;

PieVectTable.ADCINT= &cpu_timer0_isr;

EDIS;

IER |= M_INT1;

PieCtrlRegs.PIEIER1.bit.INTx7 = 1;
PieCtrlRegs.PIEIER1.bit.INTx6 = 1;

EINT; // Enable Global interrupt INTM
ERTM;

0 Bill Finger over 11 years ago in reply to Pankaj Kadam

Genius 3735 points

Mr. Kadam,

You want the code to reset and start the ADC sequence in your timer interrupt. You want the code to handle the results of the ADC operation in the ADC interrupt. They should be two separate functions.

Regards,

Bill

0 Pankaj Kadam over 11 years ago in reply to Bill Finger

Intellectual 480 points

Dear Bill,

From what you have suggested I wrote two different ISR, cpu_timer0_isr and adc_isr.

I have configured the timer0 to 100us, as a result cpu_timer0_isr is interrupted every 100us . In the cpu_timer0_isr I need to write a code that will generate ADC SOC which will be handled by adc_isr, thus capturing and values.

On page 36 of SPRU812A , it says the SOC_SEQ1 can be triggered by software but it doesn't specifies how to assign Timer0 as the SOC.

I have refereed to other controller as well the F28035 series, http://e2e.ti.com/support/microcontrollers/c2000/f/171/p/172041/635213.aspx#635213

In the 4th post, written by Markus Tamas, they have a command to set timer0 as SOC. While in my controller F28335 there is no such command.

AnalogSysctrlRegs.TRIG1SEL.bit.TRIG1SEL = 1; // Trigger by CPU Time 0

Is there a way I can similarly trigger SOC via cpu timer 0 in F28335?

Best regards,

Pankaj Kadam

0 Bill Finger over 11 years ago in reply to Pankaj Kadam

Genius 3735 points

Pankaj,

So, to trigger a conversion by software, you literally have to write software to start the conversion. For cascaded sequencing I use:

AdcRegs.ADCTRL2.bit.RST_SEQ1 = 1; // Reset SEQ1
AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 1; // Start SEQ1

For dual sequencers the code will be slightly different. Put this code in your timer ISR and you should be all set.

Regards,

Bill

0 Pankaj Kadam over 11 years ago in reply to Bill Finger

Intellectual 480 points

Dear Bill,

I have 3 dual (i.e CONV9, CONV10, CONV11, total 6 ) signals that I have to simultaneous capture.

Setting RST_SEQ1, (find attached) immediately resets sequencer to the initial CONV state. If you see the description of RST_SEQ1 in SPRU812A, it says its waits for the trigger. Its not a trigger.

I still tried it but it didn't trigger the SOC. I also checked the ADCST register. The SEQ1 is initiated but SOC of ADC doesn't take place, as the control never goes to the adc_isr in which I have a breakpoint.

I am in-between trying the XINT2, I set the GPIOxINT2SEL register , set adc_isr to handel external interrupt PIE group 5 and GPIOMUX register. Gave a 3.3V to GPIO31 as an external interrupt (similar to switching on a button) but the controller got disconnected from the IDE. I am just working on that how to give an external interrupt at the moment.

Any other hints will be helpful.

Best Regards,

Pankaj

0 Pankaj Kadam over 11 years ago in reply to Pankaj Kadam

Intellectual 480 points

Dear Bill,

I was able to solve my problem of the SOC trigger, I had commented the PIE line for the interrupt while testing for other conditions.

PieCtrlRegs.PIEIER1.bit.INTx6 = 1; // ADCINT enable

In the CPU_ISR I just wrote

AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 1 ;

PieCtrlRegs.PIEACK.bit.ACK7 = 1;

At the moment having trouble capturing the ADC values in Dual-Simultaneous mode. The code works fine for Sequential-Cascade mode.

Best Regards,

Pankaj

0 Pankaj Kadam over 11 years ago in reply to Pankaj Kadam

Intellectual 480 points

For future reference, the final changes in the code are:

Interrupt void cpu_timer0_isr(void) // ever 100us which in turn interrupts adc_isr

{

AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 1 ; // Enable SOCA from interrupt to start SEQ1

AdcRegs.ADCTRL2.bit.SOC_SEQ2 = 1 ;

PieCtrlRegs.PIEACK.bit.ACK7 = 1; // TINT0 ack

}

In ADC_Intitialization() added following changes

AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 1 ; // Enable SOCA from interrupt to start SEQ1

AdcRegs.ADCTRL2.bit.SOC_SEQ2 = 1; // Software triggered SOC SEQ2

AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 1; // Enable SEQ1 interrupt

AdcRegs.ADCTRL2.bit.INT_MOD_SEQ1=0; // 0: Interrupt every EOS

Thank you for pointing me, in the right direction.

Best Regards,

Pankaj

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F28335, ADC SOC triggered by CPU Timer