ADC Conversation time related query

utsavikalpesh — Sun, 28 Jun 2015 09:26:29 GMT

Hi,

I am working with CodeWarrior v10.3 and of MQX v4.0 (TWRK60D100M)

I am running ADC demo and is working perfectly.

What my purpose is to get approximately 1200 adc outputs within a 500ms.

My Bus frequency is 48 Mz(seen from bsp_cmp.h) and my ADC Conversation frequency is 5 Mz (seen from _adc_hw_init() in adc_kadc.c)

Now From ADC Calculator, I found My Conversion Time is 4.8us.

But I am seeing when I am trying to reduce _time_delay(100) in adc_demo.c file then number of ADC output reading is very less.

Why?? If conversation rate is fast (in us..!!) then why only _time_delay(100) is sufficient for reading output?? the delay should be in us not in ms

But when I am putting _time_delay(100) , number of ADC output reading is more.

Here is snippet to calculate numbers of ADC output reading and Time taken for it :

(I measured that to complete 1200 reading it takes appx 121 sec and 9 ms....!!)

for(i = 0; ; i++)

{

/* channel 1 sample ready? */

if (read(f_ch1, &data, sizeof(data) ))

{

printf("ADC ch 1: %4d \n ", data.result);

count++;

}

else

printf(" \n");

if (i == 1200) {

_time_get(&RequiredTime);

printf("<--------------EndTIme MILISEC : %d \n",RequiredTime.MILLISECONDS);

printf("***************EndTIme SEC : %d \n",RequiredTime.SECONDS);

printf("Count: %d",count);

printf("Pausing channel #1...");

if (IO_OK == ioctl (f_ch1, ADC_IOCTL_PAUSE_CHANNEL, NULL))

printf("stopped!\n");

else

printf("failed!\n");

}

if (i == 1200) {

i = 0;

count = 0;

printf("Resuming channel #1...");

if (IO_OK == ioctl (f_ch1, ADC_IOCTL_RESUME_CHANNEL, NULL))

printf("resumed!\n");

else

printf("failed!\n");

}

_time_delay(100);

}

Re: ADC Conversation time related query

utsavikalpesh — Tue, 30 Jun 2015 06:53:31 GMT

Hi..

I am sorry but I found later that by reducing time_period of ADC_INIT_CHANNEL_STRUCT, I am able to read 1200 adc outputs within a 29ms..!! Thats great.

Re: ADC Conversation time related query

soledad — Tue, 30 Jun 2015 17:00:30 GMT

Hello Utsavi,

Thank you for your contribution.

Regards

Soledad

topic ADC Conversation time related query in MQX Software Solutions

ADC Conversation time related query

Re: ADC Conversation time related query

Re: ADC Conversation time related query