ai_rinsn requirements

I am working on a driver and have been successful at getting some data. 
  I am struggling with the role of the analog input read instruction.

At first I thought this function was called from comedi_data_read to 
acquire a single channel of data so I implemented my ai_rinsn first was 
was able to read from a single channel.

Next I tried an instruction list and was able to read data using the 
third program in the comedi tutorial.

I have implemented my _cmdtest function and am working on the _docmd 
function.  My first plan is to do a polling and implement interrupts a 
bit later.  I am not sure how I am supposed to get data by polling 
except through my ai_rinsn function.

Hence my question, do polling, instructions, and comedi_data_read all 
use the ai_rinsn function?  If that is true, how much set-up should I be 
doing in the ai_rinsn because I already completly configure the card for 
polling and would re-doing portions everytime the ai_rinsn is called.

Bob

Received on 2004-06-08Z21:34:34