SAD Board Self Test Procedure

1)	Do a WORD write to SNDRST ($604000).  This is alledged to reset
	both the SCOM chip AND the 6502.

2)	Do a BYTE read of RDCHAR ($600000).  This is the initial read of
	the port, it should be $FF, but if not keep reading unitl it is.
	A time out of 16 milliseconds is plenty long for this -- should be
	$ff almost immediately.

3)	Do a BYTE write to WCHAR ($600000) of $07.  This is the send status
	command.

4)	The 6502 should respond within about 50 microseconds with a value that
	can be read from RCHAR.  A time out of 16 milliseconds will be plenty
	long.  The following bits in the returned status byte indicate the
	corresponding problem.

	P1BAD = 080		;80 = 6502 program PROM bad
	P2BAD = 040		;40 = 6502 program PROM bad
	P3BAD = 020		;20 = 6502 program PROM bad
	R1BAD = 010		;10 = 1st (0000) RAM bad
	R2BAD = 008		;08 = 2nd (0800) RAM bad
	IRBAD = 004		;04 = IRQs not present
	YMBAD = 002		;02 = YAMAHA timed out
	MLBAD = 001		;01 = mainline not running

Note that P1BAD, P2BAD, or P3BAD all indicate a problem in the 6502 program
PROM.  This is probably for historical reasons.  I am told by Brad that there
is currently no way to test the validity of the four PCM PROMs.

Thank you.

	Jed