obuf - digital output buffer user functions
read from and write to a 16-bit digital-output buffer.
contains the address for storing the value that
into the output buffer. For example, the call
sets all output bits low. The call
sets all bits high. By changing the parameter
various output bits can be set low or high (based on its binary
turn on or off a selected bit in the 16-bit digital-output buffer
without affecting the status of other bits in the buffer.
of the output buffer where
is between 1 and 16.
of the output buffer.
returns -1 if
is out of range.