4 ADC channel

gambler — Thu, 01 Mar 2007 09:07:15 GMT

Hi,

I am currently using 908AW32 ADC function to take measurement, but i can only activate one adc channel at a time by selecting adc channel in 'adc1sc1'. This resulting a delay in my program as i have to wait for each adc channel conversion to be completed before i can proceed with another adc channel.

Is there anyway that i can run 4 adc channel simultaneously or is there coding technique that can help me to improve the speed??

Re: 4 ADC channel

bigmac — Thu, 01 Mar 2007 09:43:15 GMT

Hello,

Tthe '9S08AW32, and other 8-bit devices, have a single ADC module. If you look at the block diagram in the data sheet (Fig 14.2), you will see that this consists of a SAR converter, plus an input multiplexer. With this arrangement, only one conversion can occur at any time.

So sequencing the required channels is the best you can do using internal resources. For rapid sequencing, you might use the ADC interrupt to commence each new conversion. This will permit you to do other things whilst waiting for each completion.

I believe some of the 16-bit MCUs do provide an automatic sequencing mode, but there is still only a single measurement at any time.

For each of the four channels, how many readings per second do you require?

Regards,

Mac

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4 ADC channel

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