On Thu, 2006-01-19 at 17:04 -0500, Gu, John A. (US SSA) wrote: > I have a ADC (Analog-to-Digital Converter, Maxim 197) integrated with a > SBC (Single Board Computer) running the Linux Kernel. The ADC has its > sample rate of 10K per second (100 usec interval). The ADC can only > operate on a single trigger and read fashion. Creating a driver is a > good way to handle it. But I don't see any proper timer or delay logic > available for my situation. By using udelay() will block all the other > processes. Does the ADC signal the CPU via a IRQ ? Or do you have to poll it to see if it ready ? In both cases it is highly unlikely that you can do that with a standard kernel, since you will only have a small < 100us window to get your sample, and in the normal kernel there can be latencies of op to several 100ms so you would lose like 1000 or more samples. I suggest you look at the RTAI project and reask your question on their mailing list, cause data acquisition is not that special and people using RTAI use it a lot. The principle in your case would be a realtime task with a latency less than the valid sample window that puts the values in a FIFO, and than another less critical task to do "something" with those values. - Erwin
