Motorola MVME172 manual Step Register and Address Action and Reference

B

VMEchip2 Tick Timer 1 Periodic Interrupt Example

Step	Register and Address	Action and Reference
4	Tick Timer 1	Write $07 to this register (set bits
	Control Register	0, 1, and 2). This enables the Tick
	$FFF40060 (8 bits)	Timer 1 counter to increment,
		resets the count to zero on
		compare, and clears the overflow
		counter.

2.Set up local bus interrupter:

Step	Register and Address	Action and Reference
5	Vector Base Register	If not already initialized by the
	$FFF40088 (8 of 32 bits)	debugger, set interrupt base
		register 0 by writing to bits 28-31.
		Refer to the Vector Base Register
		description and to Table 2-3.
		Local Bus Interrupter Summary,
		in Chapter 2.
6	Interrupt Level Register 1	Write desired level of Tick Timer
	(bits 0-7)	1 interrupt to bits 0-2.
	$FFF40078 (8 of 32 bits)
7	Local Bus Interrupter	Set bit 24 (ETIC1) to one to
	Enable Register	enable Tick Timer 1 interrupts.
	$FFF4006C (8 of 32 bits)
8	I/O Control Register 1	Write a one to bit 23 to enable
	$FFF40088 (8 of 32 bits)	interrupts from the VMEchip2. A
		zero masks all interrupts from the
		VMEchip2.

Periodic Tick Timer 1 interrupts now occur, so you need an interrupt handler. Section 3 gives the details, as follows.

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