ADC

[officialkesh]

Posted on November 19, 2013 at 06:06

Hello ,

         I am working on application in which battery voltage need to be read at regular interval say 1 ms .I am newbie to this.(1) Which one is more preferred here

ADC with DMA

or

ADC w\o DMA

?(2) How many bits accuracy would be enough ?

6-bit, 8 bit or 12 bit

?(3) Do I need to use timer ?Thanks in Advance.. #adc #discovery #board #adc-and-dma

[frankmeyer9]

Posted on November 19, 2013 at 08:57

         I am working on application in which battery voltage need to be read at regular interval say 1 ms .I am newbie to this.

How fast do you expect the battery voltage to change ? Once a minute will probably suffice, too. DMA and/or timer would probably be an overkill then.(2) How many bits accuracy would be enough ?

6-bit, 8 bit or 12 bit

? What accuracy do you need, i.e. what decisions are based upon this ? If you just check for a discharge threshold, 6 bit are probably sufficient. But since you have 12 bit, you are not in a hurry, and have no advantage in using byte-sized variables, I would go with 12 bit.

[officialkesh]

Posted on November 19, 2013 at 09:39Thank you fm.I am thinking instead of continuous mode in ADC ...if I go with Timer for battery voltage monitoring would that save battery power at all ?

[frankmeyer9]

Posted on November 19, 2013 at 10:38

I am thinking instead of continuous mode in ADC ...if I go with Timer for battery voltage monitoring would that save battery power at all ?

To check a battery voltage, I would use a software triggered single-shot mode. And one measurement about every minute is sufficient. Battery voltages hardly change in a few milliseconds (except you short them...), so you gain no information. To save power, you should rather consider how to put the device into sleep modes. Keeping the MCU in run mode permanently will quickly drain you batteries.

[officialkesh]

Posted on November 19, 2013 at 11:09

Thank you so much fm.....:)