Motorola MVME166D2, MVME166IG Multiprocessor Support, Multiprocessor Control Register Mpcr Method

Multiprocessor Support

Multiprocessor Support

The MVME166 dual-port RAM feature makes the shared RAM available to remote processors as well as to the local processor. This can be done by either of the following two methods. Either method can be enabled/disabled by the ENV command as its Remote Start Switch Method (refer to Appendix A).

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Multiprocessor Control Register (MPCR) Method

A remote processor can initiate program execution in the local MVME166 dual-port RAM by issuing a remote GO command using the Multiprocessor Control Register (MPCR). The MPCR, located at shared RAM location of $800 offset from the base address the debugger loads it at, contains one of two longwords used to control communication between processors. The MPCR contents are organized as follows:

$800

*

N/A N/A N/A (MPCR)

The status codes stored in the MPCR are of two types:

❏Status returned (from the monitor)

❏Status set (by the bus master)

The status codes that may be returned from the monitor are:

HEX	0	(HEX 00)	--	Wait. Initialization not yet complete.
ASCII	E	(HEX 45)	--	Code pointed to by the MPAR address is executing.
ASCII	P	(HEX 50)	--	Program Flash Memory. The MPAR is set to the
				address of the Flash memory program control packet.
ASCII	R	(HEX 52)	--	Ready. The firmware monitor is watching for a change.

You can only program Flash memory by the MPCR method. Refer to the

.PFLASH system call in the Debugging Package for Motorola 68K CISC CPUs User’s Manual for a description of the Flash memory program control packet structure.

The status codes that may be set by the bus master are:

ASCII	G	(HEX 47)	--	Use Go Direct (GD) logic specifying the MPAR address.
ASCII	B	(HEX 42)	--	Install breakpoints using the Go (G) logic.

MVME166IG/D2 3-21