Motorola MVME162 Manual De Usuario

Functional Description

1-19

The MVME162 includes many resources for the local processor. These include 
tick timers, software-programmable hardware interrupts, watchdog timer, 
and local bus timeout. 

Six 32-bit programmable tick timers with 1 

µ

s resolution are provided, two in 

the VMEchip2 and four in the MCchip. The tick timers can be programmed to 
generate periodic interrupts to the processor. Refer to the VMEchip2 and 
MCchip in the MVME162 Embedded Controller Programmer’s Reference Guide for 
detailed programming information.

A watchdog timer function is provided in the VMEchip2 and the MCchip. 
When the watchdog timer is enabled, it must be reset by software within the 
programmed time or it times out. The watchdog timer can be programmed to 
generate a SYSRESET signal, local reset signal, or board fail signal if it times 
out. Refer to the VMEchip2 and the MCchip in the MVME162 Embedded 
Controller Programmer’s Reference Guide for detailed programming information.

The watchdog timer logic is duplicated in the VMEchip2 and MCchip ASICs. 
Because the watchdog timer function in the VMEchip2 is a superset of that 
function in the MCchip (system reset function), the timer in the VMEchip2 is 
used in all cases except for the version of the MVME162 which does not 
include the VMEbus interface ("No VMEbus Interface" option).

Eight software-programmable hardware interrupts are provided by the 
VMEchip2. These interrupts allow software to create a hardware interrupt.

The MVME162 provides a timeout function in the VMEchip2 and the MCchip 
for the local bus. When the timer is enabled and a local bus access times out, a 
Transfer Error Acknowledge (TEA) signal is sent to the local bus master. The 
timeout value is selectable by software for 8 

µ

sec, 64 

µ

sec, 256 

µ

sec, or infinity. 

The local bus timer does not operate during VMEbus bound cycles. VMEbus 
bound cycles are timed by the VMEbus access timer and the VMEbus global 
timer.