source: multiio/pcmmio/original/README @ 9175425

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#  $Id$
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This is a port of the Winsystems Linux driver to RTEMS.

In general, the goal was to minimize changes to the user level
library and only replace Linux IO calls to the device driver
with direct access functions. 

The driver uses 4 Classic API Barriers.

--joel sherrill

Issues
======
+ The library is not reentrant. The GNU/Linux version uses global variables
  to track the state of certain variables and access to these is not protected.
  This design flaw is carried over into the RTEMS version.

+ We want to timestamp samples and the initial code did not do that.  I
  added this.

RTEMS Shell Commands
====================
The following RTEMS Shell configuration aids are defined to assist in
adding PCMMIO related commands to your shell.
  CONFIGURE_PCMMIO_ALIASES
  CONFIGURE_PCMMIO_COMMANDS

pcmmio_din - Read Discrete Inputs
    pcmmio_din [-i iterations] [-p period] [-v]
    Where: maximum iterations defaults to 1
           the period is in milliseconds and defaults to 1000

pcmmio_dout - Write a Discrete Output
    pcmmio_dout bit value
    Where: bit must be 0-47
           value must be 0 or 1

pcmmio_adc - Read Analog Inputs
    pcmmio_adc [-i iterations] [-p period] [-v]
    Where: maximum iterations defaults to 1
           the period is in milliseconds and defaults to 1000

pcmmio_adc - Write Analog Output
    pcmmio_dac dac voltage
    Where: dac must be 0-7
           voltage must be -10V to +10V

Aliases
  + adc  - alias for pcmmio_adc 
  + dac  - alias for pcmmio_dac 
  + din  - alias for pcmmio_din 
  + dout - alias for pcmmio_dout