[Techtoolslist] Jedi RAM testing

[Danny Pearson]

Hi all, I finally managed to find an hour or two to do some more on this
based on the good suggestions I got and I think it's pretty complete, either
way with a new baby about to arrive I think it's all I can do on this for
now.   I've uploaded the script (Jedi.9lc) to the /incoming directory on the
FTP server.   I'd appreciate if someone could give it a once over (a test
would be great) and check that I've got the right IC's for each designated
test.  

Thanks to James at QuarterArcade for the great script generator that
provided most of the structure for this script.

Cheers,

Dan

-----Original Message-----
From: techtoolslist-bounces at flippers.com
[mailto:techtoolslist-bounces at flippers.com] On Behalf Of John Robertson
Sent: 03 December 2009 18:06
To: Technical Tools Mail List
Subject: Re: [Techtoolslist] Jedi RAM testing

John Robertson wrote:

> Danny Pearson wrote:

>> Hi, I've got a noob question regarding ram testing and using the 

>> 9010.   I'm

>> trying to build a script to do some basic testing on Return of the Jedi

>> using a known working board as a benchmark.  So far I'm just 

>> concentrating

>> on the main CPU, not the sound CPU and I've got the ROM test all 

>> working,

>> now I'm moving on to the RAM.  The schematics for Jedi list a ram 

>> area at

>> 2400-27FF as Scrolling Playfield(high) and this appears to me to only 

>> have 4

>> data bits.   If you run the built in RAM test on the Fluke for this 

>> area it

>> fails, and from what I've managed to glean from the reading I've done 

>> this

>> is as it should be as only 4 bits of data area are returned (a nibble?),

>> whereas I assume the RAM test algorithm uses a whole 8 bits (byte).   

>> I've

>> written the following script to exercise this (and other similar RAM 

>> areas).

>> Can you tell me if I'm on the right lines?   So far I've never done 

>> anything

>> other than the built in 9010 tests so forgive me if this is a stupid

>> question;

>>

>>       REG1 = 2400

>> 1:    !LABEL 1

>>     IF REG1 = 2800 GOTO 3

>>       WRITE @ REG1 = FF

>>       WRITE @ REG1 = AA

>>     READ @ REG1

>>     IF REGE = FA GOTO 2

>>     dpy Failed Response = $1 = $E

>>       aux Failed Response = $1 = $E

>>     GOTO 3

>> 2:    !LABEL 2

>>     aux Success Response = $1 = $E

>>     INC REG1

>>     GOTO 1

>>

>> 3:     !LABEL 3

>>     dpy TEST COMPLETE

>>     aux TEST COMPLETE

>>

>>

>> Cheers,

>>

>> Dan

>>

>>   

> Looks like a good solution to the problems encountered with other 

> 4-bit RAM (2101/5101/etc.) as well. However your test should include 

> (at a minimum) F5 and FA to check that bits aren't locked.

>

> However if you only use FA and F5 then you have no way of finding 

> stuck address nodes.

>

> So it wouldn't hurt to add an offset count  - something like F0, F1, 

> F2, F3, F4, F5, F6, F7...FE, then skip one space and run that again - 

> this is to try and catch data/address rows or columns that are stuck - 

> trying to check that bits in (for example) location 000h are not the 

> same as location 010h which can happen if RAM internal (or external) 

> addressing has problems.

>

> John :-#)#

>


Actually what would work is if you have the data count climb in one 
direction then fall in the other.

Address - Data
000h - F0
001h - F1
002h - F2
...
00Eh - FE
00Fh - FF
010h - FF
011h - FE
012h - FD
...
01Eh - F1
01Fh - F0

I think that would catch stuck address nodes...

John :-#)#

-- 
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
                 www.flippers.com 
"Old pinballers never die, they just flip out"

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