Talon2000
Well-known member
I'm still trying to learn all this, so please bare with me. Basically I'm trying to figure out the best way to troubleshoot Asteroids boards. It shouldn't be as difficult as I'm making it out to be, or is it?
Ok I've got several asteroids boards with the same symtoms.
Test mode comes up good.
No Ram errors, No rom errors.
But under normal game play, get constant reset on pin 40of the CPU
Currently just trying to learn how to trouble shoot 1 board, so I haven't done all these test on the rest yet.
Have done the following
Verified Rom sigs with Fluke
Verified Ram with Fluke
Verified Bus with Fluke
Have written the following AVG test program to get + sign with Fluke
And well I get the + Sign.
WRITE @ 4000 = FF
WRITE @ 4001 = A3
WRITE @ 4002 = 00
WRITE @ 4003 = 02
WRITE @ 4004 = FF
WRITE @ 4005 = 97
WRITE @ 4006 = 00
WRITE @ 4007 = 90
WRITE @ 4008 = 00
WRITE @ 4009 = A2
WRITE @ 400A = 00
WRITE @ 400B = 00
WRITE @ 400C = 00
WRITE @ 400D = 90
WRITE @ 400E = FF
WRITE @ 400F = 33
WRITE @ 4010 = 00
WRITE @ 4011 = E0
DPY-CONFIRM PLUS PATTERN. CONT#
DPY-+=EXIT%1#
0: LABEL 0
WRITE @ 3000 = 00
IF REG1 = 25 GOTO 2
GOTO 0
2: LABEL 2
DPY-##
Went ahead and did sig analysis with the catbox to double check the address lines, and data lines.
Ran Sig analysis on the VG Address selector,and address generator.
I'm assuming since the sigs are good for those two areas, that the VG program counter is functioning correctly?
I don't have sigs for the vector generator buffer, I'll have to work on that since I have several revision boards, some with R2, and some with P2. But I'm getting out what is going in, so I assume the buffer is ok.
I've removed pin 10 of A9 (halt) and CPU still resets
I then removed pin 1 of L6 (DMAGO) and CPU still resets.
So it sounds like I have an MPU problem, but I'm not sure where to go from here.
Does that sound about right, or am I just not getting it..
Ok I've got several asteroids boards with the same symtoms.
Test mode comes up good.
No Ram errors, No rom errors.
But under normal game play, get constant reset on pin 40of the CPU
Currently just trying to learn how to trouble shoot 1 board, so I haven't done all these test on the rest yet.
Have done the following
Verified Rom sigs with Fluke
Verified Ram with Fluke
Verified Bus with Fluke
Have written the following AVG test program to get + sign with Fluke
And well I get the + Sign.
WRITE @ 4000 = FF
WRITE @ 4001 = A3
WRITE @ 4002 = 00
WRITE @ 4003 = 02
WRITE @ 4004 = FF
WRITE @ 4005 = 97
WRITE @ 4006 = 00
WRITE @ 4007 = 90
WRITE @ 4008 = 00
WRITE @ 4009 = A2
WRITE @ 400A = 00
WRITE @ 400B = 00
WRITE @ 400C = 00
WRITE @ 400D = 90
WRITE @ 400E = FF
WRITE @ 400F = 33
WRITE @ 4010 = 00
WRITE @ 4011 = E0
DPY-CONFIRM PLUS PATTERN. CONT#
DPY-+=EXIT%1#
0: LABEL 0
WRITE @ 3000 = 00
IF REG1 = 25 GOTO 2
GOTO 0
2: LABEL 2
DPY-##
Went ahead and did sig analysis with the catbox to double check the address lines, and data lines.
Ran Sig analysis on the VG Address selector,and address generator.
I'm assuming since the sigs are good for those two areas, that the VG program counter is functioning correctly?
I don't have sigs for the vector generator buffer, I'll have to work on that since I have several revision boards, some with R2, and some with P2. But I'm getting out what is going in, so I assume the buffer is ok.
I've removed pin 10 of A9 (halt) and CPU still resets
I then removed pin 1 of L6 (DMAGO) and CPU still resets.
So it sounds like I have an MPU problem, but I'm not sure where to go from here.
Does that sound about right, or am I just not getting it..
