internal temp sensor enable

Hi Ryan,

Thanks for your reply. I am trying to use the the following code to read the temperature sensor chennael count. I am using REFMSTR bit  and REFOUT bit REFCTL0 register is set. And i am using Vcc as a refrence for all the channels except the A10. For A10 i am using internal 1.5v as reference. For this code i am always receiving the constant value as a count. But if i run the BSP code from TI (adc12_a_ex8_tempSensor) i can see the variation in ADC count. I am not able to found the root cause for this ia ma debugging this issue more than a week, still i am struggling. Could you please help me this.

    // ADC12SHSx - Sample-and-Hold Source selection (Timer source - B0)
    // ADC12SSELx - Set clock Source (SMCLK)
    // ADC12CONSEQx - Repeat-sequence-of-channels mode select 
ADC12CTL1 |= 0x0C1E;
    // ADC12TCOFF = 0 to enable Temperature sensor
    // ADC12RES 12 bit conversion result resolution
ADC12CTL2 |= 0x0020;
    // ADC12ON = ADC12_A on in bit 4
ADC12CTL0 |= 0x0010;

    // Channel number is up to temp sensor channel
for (ix = 0; ix <= 10; ++ix)
{
        // clear all modulation control registers
    ADC12MCTLX[ix] = 0x00;
        // Select reference for each channel
    if(ix == 10)
    {
            // set the ref module with ref enable bit
            // for temp sensor channel alone
        REFCTL0 |= 0x0081;
            // 001b = V(R+) = AVCC and V(R-) = AVSS
            // set ADC12SREFx = 001 to set 1.5V internal voltage as reference
        ADC12MCTLX[ix] |= 0x10;
    } else
    {
            // 000b = V(R+) = AVCC and V(R-) = AVSS
            // set ADC12SREFx = 000 to set 3.3V Vcc as reference
        ADC12MCTLX[ix] &= 0x8F;
    }

    // ADC12INCHx - Input channel select as per the channel input value
ADC12MCTLX[ix] |= ix;
} 

    // Set EOS to memory control register.
ADC12MCTLX[10] |= 0x80;

    // ADC12ENC ADC12_A enable conversion in bit 1
ADC12CTL0 |= 0x0002;

ix = 0;
    // This loop will run till read all the channels
while (ix != adc_ptr->eosChanNo))
{
        // Interrupt flag check for each channel
    while (ADC12IFG == 0x0000)
    {
    } 

        // Check which channel interrupt flag is set
    for (ix = 0; ix < 10; ++ix)
    {
        if ((ADC12IFG >> ix) & 0x01)
        {
            break;
        }
    } 
        // Reset only particular channel flag
    adcReg_ptr->ADC12IFG &= ~(0x01 << ix);
    
        // Store the ADC converted value from the ADC memory register.
    *ptr[ix]) = ADC12MEMX[ix];
    ++ptr[ix];
} 

Prakash,

you already have another thread here:

Dennis

Ryan & Leo

I have made the changes as per the sample code in my code also i am polling the interrupt flag instead of interrupt method  its working fine. In sample code they are using the MCTL0 register by setting  ADC12INCHx as

1010b = Temperature diode

and  ADC12MEM0 register to store the read value. In the same code i have changed the MCTL0 to MCTL10 and the ADCTL1 register bit from 15 to 12 as 1010 to set conversion start address as channel 10 and i am expecting the converted value to be stored in ADC12MEM10. For this case i am always receiving the value is 0x0FFF;

The code as below

    // ADC12ENC bit should be cleared before initializing the ADC12_A
    // Reset the ADC Control registers & Clear Interrupt Registers
ADC12CTL0 = 0x0000;
ADC12CTL1 = 0x0000;
ADC12CTL2 = 0x0000;
ADC12IFG  = 0x0000;
ADC12IE   = 0x0000;

    // clear  memory control register.
//ADC12MCTLX[0] |= 0x00;
ADC12MCTLX[10] |= 0x00;

    // ADC core ON
ADC12CTL0 = ADC12ON;
    // using ADC12OSC as a clock
ADC12CTL1 = ADC12SHP;
ADC12CTL0 |= ADC12SHT0_8;

    // 001b = V(R+) = AVCC and V(R-) = AVSS
ADC12MCTLX[0] = ADC12SREF0 | ADC12INCH_0;
ADC12MCTLX[10] = ADC12SREF0 | ADC12INCH_10;

    // To set the channel start address
    // This is used to set the start channel as 10
ADC12CTL1 |= ADC12CSTARTADD3  | ADC12CSTARTADD1;

REFCTL0 = REFGENACT | REFON;
__delay_cycles(75);

    // Enable repeat single channel
ADC12CTL1 |= ADC12CONSEQ0;

ADC12CTL0 |= ADC12ENC;
ADC12CTL0 |= ADC12SC;

//while (!(ADC12IFG == 0x0000))
while (!(ADC12IFG & 0x0400))
{
} 

//temp = ADC12MEM0;

temp = ADC12MEM10;

RYAN and LEO

I have modified my code as per the sample code in that instead of interrupt i am using polling method. In sample code they are using MCTL0 with MEM0 memory register. I have slightly modified the to read the channel 10 value by setting MCTL10 and MEM10 and changed the ataring adress in ADCTL0 as 0101 (bit 15 -12). For this case i am always receiving the valua as 0x0FFF. Could you please guide me. The code as below

    // ADC12ENC bit should be cleared before initializing the ADC12_A
    // Reset the ADC Control registers & Clear Interrupt Registers
ADC12CTL0 = 0x0000;
ADC12CTL1 = 0x0000;
ADC12CTL2 = 0x0000;
ADC12IFG  = 0x0000;
ADC12IE   = 0x0000;

    // clear  memory control register.
//ADC12MCTLX[0] |= 0x00;
ADC12MCTLX[10] |= 0x00;

    // ADC core ON
ADC12CTL0 = ADC12ON;
    // using ADC12OSC as a clock
ADC12CTL1 = ADC12SHP;
ADC12CTL0 |= ADC12SHT0_8;

    // 001b = V(R+) = AVCC and V(R-) = AVSS
ADC12MCTLX[0] = ADC12SREF0 | ADC12INCH_0;
ADC12MCTLX[10] = ADC12SREF0 | ADC12INCH_10;

    // To set the channel start address
    // This is used to set the start channel as 10
ADC12CTL1 |= ADC12CSTARTADD3  | ADC12CSTARTADD1;

REFCTL0 = REFGENACT | REFON;
__delay_cycles(75);

    // Enable repeat single channel
ADC12CTL1 |= ADC12CONSEQ0;

ADC12CTL0 |= ADC12ENC;
ADC12CTL0 |= ADC12SC;

//while (!(adcReg_ptr->adc12Ifg == 0x0000))
while (!(ADC12IFG & 0x0400))
{
} 

//temp = ADC12MEM0;
temp = ADC12MEM10;

Thanks for your reply I have modified the ADC12SHT0 t0 ADC12SHT1 in ADCCTL0 and its working fine. And i have the following queries please clarify

1. How do we calculate the sampling time if we are using timer as a trigger source. (SMCLK of 20MHz is used as a ADC clock and the sampling rate is 100000).

2. Is there any sample code/application document available for timer trigger based ADC implementation in repeated sequence mode to read temperature sensor value too? I am developing the code for this application as i shared in my first discussion. If i get any document it will be useful

Thanks in advance

Leo Bosch said:

You also will discover that a sequence can be split up into two parts which each a different Sampling time

means "from channel 0 to 7 different sampling rtae and for channel 10 diffferent sampling rate". Is my undersatnding correct. Also i need to read the channel 0 to 10 in repeated sequence mode for timining consideration is it possible or not? Thanks in advance

Hi could any one reply .

Leo Bosch said:

You also will discover that a sequence can be split up into two parts which each a different Sampling time.

From that i have understood the sampling time is differ for temperature channel from th remaining channel? Am i wright? If, not please help me to understand correctly.