Hello, to clarify my setup:
I am using a saxotec A/D changer, which supports 16 Sensors. This is connected via RS232 to ttyS2 or ttyS3 (using foxcom). The A/D works the following way. You send a number to it and it gets the values for the given number of sensors, and sends it back. If you ask for 4 sensors you should be able to get a sampling rate of 1000Hz. Using the A/D with a normal PC this is not a problem, but with the FoxBoard it seems that the maximum frequency is 100Hz. I activated the DMA fast timer and I also used without DMA. It seems it does not make a difference (using Kernel 2.4). The fastest sampling rate I can get is 100Hz. In the code I used "select" to wait for the next data on the RS232. with kernel frequency I meant the timer frequency discussion from http://kerneltrap.org/node/5411 many thanks Juergen
