Motorola MVME187 User Manual

Functional Description

2-23

The MVME187 includes many resources for the local processor. 
These include tick timers, software programmable hardware 
interrupts, watchdog timer, and local bus timeout. 

Four 32-bit programmable tick timers with 1 

µ

s resolution are 

provided, two in the VMEchip2 and two in the PCCchip2. The tick 
timers can be programmed to generate periodic interrupts to the 
processor. 

A watchdog timer function is provided in the VMEchip2. 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. 

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

The MVME187 provides a timeout function 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 infinite. 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.