Typewriter User Manual

8- 28 MC68340 USER’S MANUAL MOTOROLA
• Enable the counter prescaler (CPE bit).
• Select the selected clock (CLK bit).
• If the PCLK bit is set, select the POTx bits.
• Select the mode of operation (MODEx bits).
• Select the operation of TOUT (OCx bits).
8.5.2 Timer Module Example Configuration Code
The following code is an example of a configuration sequence for the timer module.
***************************************************************************
* MC68340 basic timer module register initialization example code.
* This code is used to initialize the 68340's internal timer module
* registers, providing basic functions for operation.
* It sets up timer1 for square wave generation.
***************************************************************************
***************************************************************************
* equates
***************************************************************************
MBAR EQU $0003FF00 Address of SIM40 Module Base Address Reg.
MODBASE EQU $FFFFF000 SIM40 MBAR address value
***************************************************************************
* Timer1 module equates
TIMER1 EQU $600 Offset from MBAR for timer1 module regs
MCR1 EQU $0 MCR for timer1
* Timer1 register offsets from timer1 base address
IR1 EQU $604 interrupt register timer1
CR1 EQU $606 control register timer1
SR1 EQU $608 status register timer1
CNTR1 EQU $60A counter register timer1
PRLD11 EQU $60C preload register 1 timer1
COM1 EQU $610 compare register timer1
***************************************************************************
***************************************************************************
* Initialize Timer1
***************************************************************************
LEA MODBASE+TIMER1,A0 Pointer to timer1 module
* Disable timer1
CLR.W CR1(A0)
* Clear the TO, TG, and TC bits
CLR.W SR1(A0)
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cale Semiconductor,
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