user manual

Functional Description

2-23

Local Resources

The MVME187 includes many resources for the local processor.

These include tick timers, software programmable hardware

interrupts, watchdog timer, and local bus timeout.

Programmable Tick Timers

Four 32-bit programmable tick timers with 1 µs 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.

Watchdog Timer

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.

Software-Programmable Hardware Interrupts

Eight software-programmable hardware interrupts are provided

by the VMEchip2. These interrupts allow software to create a

hardware interrupt.

Local Bus Timeout

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 µsec, 64 µsec, 256 µsec,

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.