On Monday, October 05, 2015 8:54 AM, Ian Abbott wrote: > On 02/10/15 01:23, H Hartley Sweeten wrote: >> According to the users manual, the conversion timing (scanrate) is fixed >> to 100, 50, or 25 kHz. The pacer clock is then used to trigger each scan. >> >> Currently this driver tries to fake other conversion speeds by always >> sampling the inputs at 100 kHz and using the pacer clock to trigger each >> conversion. It does this by setting the SCANLIST_START bit for each >> entry in the scan list. According to the users manual, this bit has to be >> set for the first (and ONLY the first) entry of the scan list. > > I'm not sure. If you read the remainder of that paragraph in the > manual, it says you can use that bit to chop the scan list into pieces, > which is what I think the original code is doing. > > I'd say it's safest to leave the timing alone, as presumably any > existing users are happy with the way it is. But, the last part of the paragraph on page 30 says: "Although this may be useful for diagnosis or special applications, it is the abnormal way of setting the first channel flag and should be avoided unless absolutely necessary." There are also advantages to allowing the slower conversion times. Depending on the A/D converter, the slower conversion time will allow a better sample to be acquired. With the current command support the conversion is fixed at 100 kHz even if the user specifies a slower speed. But, if you prefer this patch to be dropped I can redo the series. Regards, Hartley _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
