Echelon Neuron C - Manual (Page 114)

94 Functions
The io_in( ) call has an unsigned short return-value that is the actual number of
bits read.
magcard
For magcard input objects, the syntax is:
io_in ( magcard-input-obj , buf );
buf A pointer to a 20 byte buffer of unsigned short bytes,
which can contain up to 40 hex digits, packed 2 per byte.
The io_in( ) call has a signed short return-value that is the actual number of hex
digits read. A value of -1 is returned in case of error.
magcard_bitstream
For magcard_bitstream input objects, the syntax is:
io_in ( magcard-bitstream-input-obj, buf, count );
buf A pointer to a buffer of unsigned short bytes, sufficient to
hold the number of bits (packed 8-per-byte) to be read.
count The number of data bits to be read.
The io_in() call has an unsigned long return-value that is the actual number of
data bits read. This value is either identical to the count argument, or a smaller
number that indicates a timeout event occurred during the read.
magtrack1
For magtrack1 input objects, the syntax is:
io_in ( magtrack1-input-obj , buf );
buf A pointer to a 78 byte buffer of unsigned short bytes,
which each contain a 6-bit character with parity stripped.
The io_in( ) call has an unsigned short return-value that is the actual number of
characters read.
muxbus
For muxbus I/O objects, the syntax is:
io_in (
muxbus-io-obj [, addr ]);
addr An optional address to read. Omission of the address
causes the firmware to reread the last address read or
written (muxbus is a bi-directional I/O device).
neurowire
For neurowire I/O objects, the syntax is:
io_in ( neurowire-io-obj , buf , count );
buf A (void *) pointer to a buffer.
count The number of bits to be read.