#ident "ide/godzilla/xbow/Plan: $Revision 1.1$"


		XBOW LEVEL 1 DIAG PLAN
		=======================

Summary
-------
The Xbow level 1 Diagnostics check as much functionality as possible for a
system comprising the processor, the heart, the crossbow, the bridge 
and the local memory (plus eprom and serial port and scsi).

Background
----------
The Xbow is the only ASIC on the frontplane.
The frontplane also supplies power to the other logic boards.
Xbow provides 16 unidirectional connection between 8 ports: 
4 of these ports are 16 bits wide, 4 are 8 bits wide.

if the frontplane is not installed correctly, nothing can run 
(because there is no path to the PROM). 

The objective is to come up with a fool-proof, user-installable, mechanism
for the replacement of the frontplane in the field, by the user.

For IP30, the default configuration is 8=heart, F=bridge.

Objective
---------
What ide can do is some basic sanity tests:
- test/report  widget present and widget alive off Xbow; 16 (8, 9, A, B) 
	or 8 (C, D, E, F) bits. 
- R/W test
- other functional tests:
	access error test
	basic xfer tests between alive widgets (?)
	bad LLP tests

Execution
---------
write/debug code with existing - limited - xbow sable model in sable simulator.



