Hardware manual

EUROCOM-17-5xx 3 Programmers Reference

Hardware Manual 55

3.3.2.5 A16 Slave

Interface

(ICMS, ICGS)

A very useful feature of the VIC is a set of registers and switches for

message passing or event signaling.

There are eight bytewide general-purpose interprocessor communication

registers accessible from the VMEbus or the local bus (CPU).

• Registers 0 to 4 are general-purpose dual-port registers.

• Register5 is a dual-port read-only ID register to identify the VIC and its

revision level.

• Register6 is a module status register which is read-only from the

VMEbus.

• Register 7 provides semaphores for registers 0-4 and several system

control functions like a remote reset function.

Four ‘Interprocessor Communication Module Switches’ (ICMS) and four

‘Interprocessor Communication Global Switches’ (ICGS) are provided by

the VIC. These are bytewide mailbox switches to signal events by

generating an interrupt to the local CPU if accessed from the VMEbus. To

signal dedicated events/messages the ICMS locate a unique set of

addresses. To support this feature, two separate ICF address decoders are

installed on the EUROCOM-17-5xx board. The ICF1 decoder for

dedicated board specific messages and the ICF2 decoder to feature global

messages. Each decoder is enabled separately.

The intercommunication registers within the VIC chip are accessible in

A16 VMEbus address space only.

For programming the ICF decoder registers, see the description of the

slave base address register, slave mask register and enable slave select

Use the RMon setup menu to change the register values. Within the

256-byte space the VIC chip locates several intercommunication registers.