Memory test for Atom?

discussion of games, software, hardware & emulators relating to the Acorn Atom
mattd
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Memory test for Atom?

Postby mattd » Sat Jun 24, 2017 3:38 am

Hi all,

Would anyone know of a memory (Ram) test program for the Atom. Mine seems to work fine, it's expanded but many games seem to crash - I suspect dodgy ram? Anyone have any advice?
Thanks
Matt

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Multiwizard
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Re: Memory test for Atom?

Postby Multiwizard » Sat Jun 24, 2017 6:06 am

Hi,

will this do?


Greetings, Wim... :-)
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mattd
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Re: Memory test for Atom?

Postby mattd » Sat Jun 24, 2017 7:07 am

Thanks!! :) No doubt bad news when I run it!! [-o<

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Re: Memory test for Atom?

Postby mattd » Sat Jun 24, 2017 7:25 am

Hi Multiwizard,

I ran it fine - but I think it just identifies RAM / ROM chips - not tests them. I've got 12 blocks of &0400 (12k) - so that's good but I suspect that some are faulty

Matt

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Multiwizard
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Re: Memory test for Atom?

Postby Multiwizard » Sat Jun 24, 2017 7:32 am

mattd wrote:Hi Multiwizard,

I ran it fine - but I think it just identifies RAM / ROM chips - not tests them. I've got 12 blocks of &0400 (12k) - so that's good but I suspect that some are faulty

Matt
It indeed just identifies RAMs...

I don't think there is a program which can actually check if they are not faulty... :-k


Greetings, Wim... :-)

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oss003
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Re: Memory test for Atom?

Postby oss003 » Sat Jun 24, 2017 8:27 am

Well you can expand the program to accordingly write #00, #FF, #AA and #55 to every byte and read if the data is ok.
Takes a while in Basic but is possible.

The easiest way is to fill blocks with definied data and then copy the block to #8000 in clear 4.
This way you can see if there's something wrong.

Greetings
Kees

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hoglet
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Re: Memory test for Atom?

Postby hoglet » Sat Jun 24, 2017 8:30 am

Here's a small memory test program you could type in from Atomic Theory and Practice:

Code: Select all

    1 REM MEMORY TEST
   10 INPUT"FROM"A,"  TO"B
   20 DO ?12=0; R=!8
   30 FOR N=A TO B STEP4;!N=RND; NEXT N
   35 ?12=0; !8=R
   40 FOR N=A TO B STEP4
   50 IF !N<>RND PRINT'"FAIL AT "&N'
   60 NEXT N
   70 P." OK"; UNTIL 0

It's in the Atom Software Archive, if you have that installed on your AtoMMC SD Card. (Section D, named RAM TEST).

Dave

mattd
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Re: Memory test for Atom?

Postby mattd » Sun Jun 25, 2017 4:25 am

Thanks Dave,

Even this program doesn't run without an odd error - 'Error 94 Line 61654'

Am I right to suspect RAM or any other ideas?

Matt

Edit - thought I'd add the screen from the RAMTEST program Multiwizard recommened - might help
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roland
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Re: Memory test for Atom?

Postby roland » Sun Jun 25, 2017 7:24 am

An easy way to check your ram is to swap the lower memorchips with the video ram. If there are any faulty ram ic's you will probably notice white dots or short lines in clear 4.

You can invert the screen with

FOR A=#8000 TO #97FF STEP 4;!A=!A:-1;NEXT

And you should not see any black pixels or lines.

You can run this test for the 'original' video memory and the swapped memory.

Beware that you will see some pixels after the test has finished. This is the promp, so thatis normal. It's a simple test but it gives a rough indication about your memory.
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oss003
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Re: Memory test for Atom?

Postby oss003 » Sun Jun 25, 2017 8:40 am

mattd wrote:Even this program doesn't run without an odd error - 'Error 94 Line 61654'

Am I right to suspect RAM or any other ideas?

Hi Matt,

If the program is at #2900 and you are testing this area, the program will be overwritten by the test and generates an error.
If you type P.&TOP and start testing after this address, it should work fine.

This means that you can test the areas:

#2800 - #28FF
TOP - #3BFF
#8200-#97FF

Greetings
Kees

mattd
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Re: Memory test for Atom?

Postby mattd » Mon Jun 26, 2017 9:07 am

Thanks Kees,

Getting plenty of OK's at the moment - I'm trying to work out those nested loops - what's the 'step 4' for - wouldn't it go through the addresses sequentially? I'm running for #2800 to #28ff (256 bytes right?) and it's going for a while.... :)

Thanks

Matt

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oss003
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Re: Memory test for Atom?

Postby oss003 » Mon Jun 26, 2017 12:03 pm

The Atom has 2 peek/poke instructions:

? means a 1 byte integer and
! means a 4 byte integer.

Peek/poke with 4 bytes integers is faster but you have to step by 4 bytes through the loop.

Greetings
Kees

mattd
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Re: Memory test for Atom?

Postby mattd » Tue Jun 27, 2017 12:59 am

That Makes sense now Kees - thanks

So, I think my RAM is OK (#2800 and above). Am I right to suspect the Page Zero RAM to be faulty - remember some software works fine, others crash? Obviously I can't test that through the same method!!

Would it be as straight forward as swapping 2 of the ram chips, say at #9000 into the page zero slots and seeing if that makes a difference? The actual chips used for video ram and program storage are the same physically right?

Thanks again for all of your time and patience!! :D
Matt

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roland
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Re: Memory test for Atom?

Postby roland » Tue Jun 27, 2017 7:25 am

I don't think your zero page ram is faulty. But it won't do any harm if you swap the zero page ram with two other ram chips (either video or program memory). That makes you sure that the zero page ram is either working fine or is faulty.

If all the ram is working OK then you should go look for bad contacts in the sockets of the other chips, or for dry solder joints on the main board. The random errors can occur when there are memory-read faults caused by bad contacts. Have there been modifications on the main board that might have caused short circuits or broken tracks?
256K + 6502 Inside
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mattd
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Re: Memory test for Atom?

Postby mattd » Tue Jun 27, 2017 8:44 am

Thanks Roland for you advice,

I'll take a look at the board at try swapping the zero ram out. It looks in good condition from what I recall. One thing to note is when I say 'random crash', each piece of software / game crashes at pretty much the same pint. So Atom Invaders for example gets to the exact same spot of displaying the invaders and freezes. So consistent and random if you get me!

Matt

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oss003
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Re: Memory test for Atom?

Postby oss003 » Tue Jun 27, 2017 10:44 am

Hi Matt,

If a CLEAR4 screen looks ok and after inverting it, it still looks ok, I would say that your video RAM is ok and swap all the video RAM with the user RAM.

Then do the CLEAR4 test again to see if there are bad RAM chips. If that also looks ok then you have another problem.

BTW did the RAM test report errors?

Greetings
Kees

mattd
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Re: Memory test for Atom?

Postby mattd » Wed Jun 28, 2017 9:08 am

OK, the plot thickens!
On Clear 4, there's a byte (or word!) near the top (see top image) - I assume this is the cursor as more appear as you type? So all good?
However, blind typing the invert code FOR A=#8000 TO #97FF STEP 4;!A=!A:-1;NEXT there's the usual noise as the code runs, but no complete white screen? Results are below image
Strange?

Matt

PS - appreciate the time you are spending to help my trouble shouting - in the interim, I'll open him up to see if there's any obvious connection faults to the eye.
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roland
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Re: Memory test for Atom?

Postby roland » Wed Jun 28, 2017 9:16 am

The screen looks fine.

Another method to make the screen white is this one:

FOR A=#8000 TO #97FF STEP 4;!A=-1;NEXT

Does that work?
256K + 6502 Inside
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mattd
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Re: Memory test for Atom?

Postby mattd » Wed Jun 28, 2017 9:22 am

Yes Roland, except a couple of black bits / bytes which I assume are the cursor.

In the interim, I did take the case off and double check all ram is pushed in enough within reason. The page zero actually moved a bit and I was hopeful! But same result when I run Astrobird - graphic glitch then crash to text screen with an Error 94 with no line this time!

Matt

PS - so maybe time to swap the video ram into lower ram? Shal I swap out the page zero (IC 51 & 51 right?)?

2nd Edit - maybe another clue is that some games / software are fine - I've just 'found' Moon Patrol (nice take on the game!) - works just fine.

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hoglet
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Re: Memory test for Atom?

Postby hoglet » Wed Jun 28, 2017 9:30 am

mattd wrote:Would anyone know of a memory (Ram) test program for the Atom. Mine seems to work fine, it's expanded but many games seem to crash - I suspect dodgy ram? Anyone have any advice?

I have a couple of questions that might help narrow this down....

Do any games run reliably? Bug Byte Galaxians for example?

Could you post a photo of your Atom board?

Does it have a floating point ROM installed in IC21? Some games do require this.

Do you get random crashes when you are using it normally, e.g. when typing in and running simple basic programs?

Dave

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Multiwizard
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Re: Memory test for Atom?

Postby Multiwizard » Wed Jun 28, 2017 9:36 am

mattd wrote:Mine seems to work fine, it's expanded but many games seem to crash - I suspect dodgy ram? Anyone have any advice?

It also can depend on which ROM you use in IC24, a game could need a P-Charm, but another game could need the AXR1, JBOX or another type of ROM...


Greetings, Wim... :-)
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hoglet
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Re: Memory test for Atom?

Postby hoglet » Wed Jun 28, 2017 9:50 am

mattd wrote:OK, the plot thickens!
On Clear 4, there's a byte (or word!) near the top (see top image) - I assume this is the cursor as more appear as you type? So all good?
However, blind typing the invert code FOR A=#8000 TO #97FF STEP 4;!A=!A:-1;NEXT there's the usual noise as the code runs, but no complete white screen? Results are below image
Strange?

This is indeed strange, assuming you didn't make a mistake blind typing.

Can you try the following:

Code: Select all

A=#9000
!A=0
PRINT &!A
!A=!A:-1
PRINT &!A
!A=-1
PRINT &!A
!A=!A:-1
PRINT &!A

mattd
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Re: Memory test for Atom?

Postby mattd » Wed Jun 28, 2017 10:04 am

Hi Dave,

Yes some games, i.e. Moon Patrol works fine, however BB Galaxians doesn't - starts with Glitches then crashes - both using '*Menu' and loading directly.

Photo attached below- hires

IC21 is present - I haven't tested beyond mucking around with the A&F Utilikit that came with my Atom - I've since swapped that utility rom out for SirMorris's MMC rom of course.

simple basic programs I type are fine - I might try to basic programs from th archive and see what happens..

Hi Multiwizrd - not sure what ROm is in IC24 - can I get a signature from the ROMTEST program in the archive?

Matt
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mattd
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Re: Memory test for Atom?

Postby mattd » Wed Jun 28, 2017 10:13 am

Also Dave,

The test in #9000 work fine - 0 to all the F's - F's again with the !A=-1, and then back to 0

Matt

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oss003
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Re: Memory test for Atom?

Postby oss003 » Wed Jun 28, 2017 10:21 am

Only notice a missing C11 .....

Greetings
Kees
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hoglet
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Re: Memory test for Atom?

Postby hoglet » Wed Jun 28, 2017 10:24 am

mattd wrote:The test in #9000 work fine - 0 to all the F's - F's again with the !A=-1, and then back to 0

That good. Can you try your original test again:

Code: Select all

CLEAR 4;FOR A=#8000 TO #97FF STEP 4;!A=!A:-1;NEXT

You are missing the 6522 - a few games depend on this, but not Galaxians (I just tested it).

Do you have a spare 6502 you could swap in?

Dave

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oss003
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Re: Memory test for Atom?

Postby oss003 » Wed Jun 28, 2017 10:35 am

Reseating some IC's sometimes help, like the 6502, 6847 and 8255.

mattd
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Re: Memory test for Atom?

Postby mattd » Wed Jun 28, 2017 10:50 am

OK Dave,
The original test just worked fine. I tested a basic game (with some mc) Grand Prix - works fine.

No spare 6502 chip. I might try resetting the chips..although it's getting late here and I've a a couple of beers :D

EDIT - main chips all reseated nicely :D - same results though :?

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Re: Memory test for Atom?

Postby mattd » Wed Jun 28, 2017 11:19 am

Dave - a probably dumb question, but are all 6502 chips standard? I've got a 'for repairs' spare vic-20 sitting here...

Matt

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hoglet
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Re: Memory test for Atom?

Postby hoglet » Wed Jun 28, 2017 11:28 am

mattd wrote:Dave - a probably dumb question, but are all 6502 chips standard? I've got a 'for repairs' spare vic-20 sitting here...

The MOS 6502 from a VIC 20 should work fine in an Atom.


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