PEP Modular Computers Modular Computers RS485

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SMART I/O User’s Manual

March 12, 1996

Page 2 - 36

Chapter 2 SMART-BASE

O_PRELOAD : With this call the counter preload register can be

set. The syntax is as follows :

<RetVar> := OPERATE(<iovar>, O_PRELOAD, <prevar>);

where the

<iovar>

is typically t_in and

is the value for the preload register

which lies between 1 and 0xFFFFFF.

O_START_CNTDWN : This function starts the counter counting-down.

When the counter reaches zero, it rolls over to the

maximum value of 0xFFFFFF on the following

clock pulse and starts afresh. The syntax is as

follows :

<RetVar> := OPERATE(<iovar>,O_START_CNTDWN,<prevar>);

where the

<iovar>

is a variable attached to the

Timer I/O (typically t_in) and

may be

one of

OA_PITCLOCK

for selection of the

6 MHz/32 clock input or

OA_TIN

for selection of

t_in inputs.

PEP Modular Computers Modular Computers RS485 - Page 76