Documentation for the timer module

(This documentation was generated automatically from the file timer.asm by asmdoc on Nov 22, 2000.)


Version: 1.0
Author: Ken Clowes

This module contains utility timer routines.


           
Summary
doPeriodically            Defines a subroutine that shoud be executed periodically.

           
Details

doPeriodically

Defines a subroutine that shoud be executed periodically. The staring address of the subroutine is specified in register IX and the number of clock cycles between invocations is specified by the 16-bit unsigned number in Accumulator D.

Timer 5 is used and may not be used by the application for other purposes. The routine can be called whether interrupts are masked or unmasked. This setting of the I-bit is restored when this setup subroutine returns. Of course, the I-bit must be cleared before the specified function will run periodically.

Another subroutine can be specified in subsequent calls. If the specified subroutine starts at address 0, nothing happens and periodic OC5 timer interrupts are disabled.

Parameters:
AccD Number of E-clock cycles between invocations
IX Starting address of subroutine.
Returns:
Nothing
Side effects:
none