Not able to do analog sensor data transmission using ZSTack(ZStack-Exp5438-2.5.1) (Generic App Sample Example)

Sir,
We are not able to do correct data transmission. Whatever values we adjust for the timeout delay, adc sampling frequency we are not able to get smooth wave at receiver side for every frequency.

Current settings are :

Packet data size : 80 bytes
ADC Sampling frequency: 725.33 Hz
Timeout delay: 250ms

I am getting smooth sine wave for frequencies that are multiple of 9Hz i.e. 9 , 18, 27, 90, 180, 270, etc...

According to me this is because

(1/725.33)*80 = 110ms

1/9 = 111ms

So, the values are correct but for any frequency other than 9Hz the samples are taken at wrong place so their reconstruction is not proper but for 9Hz and its multiples the samples are taken at proper place and so the reconstruction.

I think above inference is wrong because for some different settings when I applied the same logic I did not get the expected result

What should I do now to get smooth sine wave for frequencies between 0.1Hz to 250Hz?

Also as discussed in different thread we are not able to set the timeout value less than 150 ms so is there a solution for that.

Sir,

I am calling the ADC in  GenericApp_Init function and adc triggering is being done in process event before sending the data.

ADC being used is of 8 bit resolution.

I have used following code as posted:

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

#pragma vector=ADC12_VECTOR

__interrupt void ADC12_ISR(void)

{

//ADC12CTL0 &= ~ADC12ENC; // Disable ADC12 conversions

//REFCTL0 &= ~REFON; // Disable reference

theMessageData[index1] = (ADC12MEM0);

index1++;

if (index1 == 80)

{

index1 = 0;

ADC12CTL0 &= ~ADC12ENC;

__bic_SR_register_on_exit(LPM0_bits);

}

}

void adc(void)

{

P6SEL |= BIT7; // Pin 7.6 and 7.7 are inputs from the accelerometer to the ADC => they are configured as inputs to the ADC

P6DIR &= ~BIT7;

P7DIR=BIT5;

P7OUT=BIT5;

REFCTL0 |= REFMSTR+REFVSEL_2+REFON+REFTCOFF;

ADC12CTL0 = ADC12ON + ADC12SHT0_6+ ADC12MSC;

ADC12CTL1 = ADC12SHP + ADC12CONSEQ_2 + ADC12SSEL_3 +ADC12DIV_3 + ADC12PDIV ;  //7075hz hz sampling freq

ADC12CTL2 = ADC12RES_0; // +ADC12TCOFF; // Resolution=08 bits, 9 clock cycle conversion time on time

ADC12MCTL0 = ADC12INCH_7+ ADC12SREF_1;

ADC12IE = BIT0;

__delay_cycles(200000); // Allowing reference voltage to stabilize

}

void adctrigger(void)

{

ADC12CTL0 |= ADC12ENC | ADC12SC;

// ADC12CTL0 |= ADC12SC;

__bis_SR_register(LPM0_bits+GIE);

__no_operation();

}

///////////////////////////////////////////////////////////////////////////////////////////////////////////

Sir, 

As I explained earlier, adc()  is being called in GenericApp_Init function and adctrigger()  is being called in process event GenericApp_ProcessEvent function before transmission of data using GenericApp_SendTheMessage() function

Sir,

I am using the following code for transmitting the data :

////////////////////////////////////////////////////////////////////////////////////////////////

if ( events & GENERICAPP_SEND_MSG_EVT )

 {

        adctrigger();

   // Send "the" message

   GenericApp_SendTheMessage();

   // Setup to send message again

   osal_start_timerEx( GenericApp_TaskID,

                       GENERICAPP_SEND_MSG_EVT,

                       GENERICAPP_SEND_MSG_TIMEOUT );

   // return unprocessed events

   return (events ^ GENERICAPP_SEND_MSG_EVT);

 }

/////////////////////////////////////////////////////////////////////////////////////////////////////

Sir,
I will be checking my ADC_ISR code for MSP430,meanwhile can u please suggest some ADC_ISR codes.
it will be of very much help.
thank you

Sir,

You said: ADC interrupt would keep rising in your application and I think this would make Z-Stack doesn't have spare time to send message.

Please can you elaborate on this. I thought we are supposed to collect the data and then send it on the air and that was our approach for constructing ADC_ISR logic.