Digital Signal Analyzer suggestions needed

[8BIT]

My friend is trying to fix an old arcade game and is looking for the following:

Quote:

Hey, Daryl, do you know of any boards, kits or projects that will monitor the data, address and control lines of a 6502? By itself or connected to a PC. I bought a 1983 Battlezone arcade machine and am getting close to all the troubleshooting I can do with a 4 chan scope and multimeter. Kinda like the ROMULATOR kit.

Can anyone recommend a solution at a reasonable cost? My friend has good electronic skills so a kit or DIY reference would be ok.

thanks!

Daryl

[barrym95838]

I think hoglet made a nice kit that would fit the bill, but I'm link-challenged at the moment.

[hoglet]

barrym95838 wrote:

I think hoglet made a nice kit that would fit the bill, but I'm link-challenged at the moment.

Was this the project you were thinging about?
https://github.com/hoglet67/6502Decoder/wiki

It's a post processor for logic analyzer capture files that reconstructs the processor state (for a 6502, 65C02, 65816). It's written in vanilla C, so should be compilable on most systems. There is also a Z80 version in a seperate project.

It works with any 16-bit logic analyzer, but one that can do synchronous capture (on the falling clock edge) is preferred. It needs a connection to the data bus, plus a few control signals(Phi2, RnW, Sync, Rdy, nRST). No address bus connection is used; all addresses are inferred from what's seen on the data bus.

It produces instruction traces like this:

Code: Select all

???? :          : RESET !!      A=?? X=?? Y=?? SP=?? N=? V=? D=? I=1 Z=? C=?
D9CD : A9 40    : LDA #40       A=40 X=?? Y=?? SP=?? N=0 V=? D=? I=1 Z=0 C=?
D9CF : 8D 00 0D : STA 0D00      A=40 X=?? Y=?? SP=?? N=0 V=? D=? I=1 Z=0 C=?
D9D2 : 78       : SEI           A=40 X=?? Y=?? SP=?? N=0 V=? D=? I=1 Z=0 C=?
D9D3 : D8       : CLD           A=40 X=?? Y=?? SP=?? N=0 V=? D=0 I=1 Z=0 C=?
D9D4 : A2 FF    : LDX #FF       A=40 X=FF Y=?? SP=?? N=1 V=? D=0 I=1 Z=0 C=?
D9D6 : 9A       : TXS           A=40 X=FF Y=?? SP=FF N=1 V=? D=0 I=1 Z=0 C=?
D9D7 : AD 4E FE : LDA FE4E      A=80 X=FF Y=?? SP=FF N=1 V=? D=0 I=1 Z=0 C=?
D9DA : 0A       : ASL A         A=00 X=FF Y=?? SP=FF N=0 V=? D=0 I=1 Z=1 C=1
D9DB : 48       : PHA           A=00 X=FF Y=?? SP=FE N=0 V=? D=0 I=1 Z=1 C=1
D9DC : F0 09    : BEQ D9E7      A=00 X=FF Y=?? SP=FE N=0 V=? D=0 I=1 Z=1 C=1
D9E7 : A2 04    : LDX #04       A=00 X=04 Y=?? SP=FE N=0 V=? D=0 I=1 Z=0 C=1
D9E9 : 86 01    : STX 01        A=00 X=04 Y=?? SP=FE N=0 V=? D=0 I=1 Z=0 C=1
D9EB : 85 00    : STA 00        A=00 X=04 Y=?? SP=FE N=0 V=? D=0 I=1 Z=0 C=1
D9ED : A8       : TAY           A=00 X=04 Y=00 SP=FE N=0 V=? D=0 I=1 Z=1 C=1
D9EE : 91 00    : STA (00),Y    A=00 X=04 Y=00 SP=FE N=0 V=? D=0 I=1 Z=1 C=1
D9F0 : C5 01    : CMP 01        A=00 X=04 Y=00 SP=FE N=1 V=? D=0 I=1 Z=0 C=0
D9F2 : F0 09    : BEQ D9FD      A=00 X=04 Y=00 SP=FE N=1 V=? D=0 I=1 Z=0 C=0
D9F4 : C8       : INY           A=00 X=04 Y=01 SP=FE N=0 V=? D=0 I=1 Z=0 C=0
D9F5 : D0 F7    : BNE D9EE      A=00 X=04 Y=01 SP=FE N=0 V=? D=0 I=1 Z=0 C=0

Dave

[BigEd]

Dave has made a marvellous thing there, very much recommended for everyone with a 6502 diagnosis challenge.

[plasmo]

I like the idea of inferring instructions from data because it reduces the amount of data collected significantly. I have a simple logic analyzer for RC2014, a re-purposed CPLD prototype board, that snoops the processor bus and sent data out on serial port at high rate. How fast the processor can ran is constrained by how much data and how fast the serial port operates. Dave's tool is helpful, thank you.
Bill

[BigDumbDinosaur]

8BIT wrote:

My friend is trying to fix an old arcade game...Can anyone recommend a solution at a reasonable cost?

What might be “reasonable cost?”

[Martin A]

Another Hoglet project : https://github.com/hoglet67/AtomBusMon/wiki

using a GODIL to replace the CPU entirely

[BigEd]

That's also splendid, but GODIL are not available any more, I think, so you will probably need some other FPGA board and a level shifter board. One remarkably excellent feature is that the 6502 is assisted by a second CPU which runs a nicely featured monitor with breakpoints, watchpoints, disassembler.

[8BIT]

Thank you everyone for your responses. Much appreciated!

Daryl