User`s manual

OP7100 Software
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Digital I/O
No specific drivers have been written for the OP7100 digital I/O. The
inport and outport functions in the Dynamic C BIOS.LIB library can
be used to read the inputs and write the outputs. The eight digital inputs
(DIN0–DIN7) are bitmapped bits 0 through 7 of the input at 0x4140. Each
digital output (OUT0–OUT7) is controlled by bit 0 at 0x4140 through
0x4147.
For example, OUT2 can be turned on using the following statement.
outport( 0x4142,1 );
Likewise, OUT7 can be turned off using the following statement.
outport( 0x4147,0 );
The inport function reads all eight inputs simultaneously, so the bitwise
AND operator (&) is useful in checking the status of a particular input. For
example, the statement
if( inport(0x4140) & 0x04 )
can be used to check whether DIN2 (whose bit mask is 0x04) is on.
Likewise
if( inport(0x4140) & 0x80 )
can be used to check the status of input DIN7.
The Dynamic C function IBIT can be used to determine the state of one
input bit. For example, to check DIN2 (which is bit 2 of the inputs), use the
statement
if( IBIT(0x4140,2) )
instead of the more complex statement below.
if( inport(0x4140) & 0x04 )
While IBIT works well for the digital inputs, its output equiv-
alents, ISET and IRES, will not work with the digital output
bits because the output register of the OP7100 is write-only.
ISET and IRES will only operate on output registers whose
current state can be read by the processor.
Refer to the Dynamic C Function Reference manual for more
information on the use of these functions.
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