8-bit Microcontrollers中的主题 Re: differential measurement

differential measurement

juliancox — Wed, 02 May 2018 08:36:50 GMT

Is there any way to make a differential measurement using the A/D converter on any of the S08 devices? I am migrating an application from a '51 device where the A/D provides access to the Ain+ and Ain-. I am not sure if using 2 A/Ds and getting the difference in software will be reliable enough as it will probably double the error and I don't want to add a separate device.

Re: differential measurement

vicentegomez — Wed, 02 May 2018 21:48:52 GMT

You can use two adc channels

Or you can use the analog comparator.

Just remember that the adc can not get negative inputs

regards

Vicente

Re: differential measurement

juliancox — Fri, 04 May 2018 09:35:15 GMT

Using two channels is not a differential measurement - it is a post-conversion calculation. Each channel will be subject to the usual errors and therefore the potential error will be doubled. Also both inputs will be positive. With approximately 5000000 (sic) variants of the S08 I was really wondering if one of them had a differential input. If they could do it for the comparator, why not the A/D?