Got myself an Atom... Where to start?

discussion of games, software, hardware & emulators relating to the Acorn Atom and Acorn System machines.
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jonb
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Got myself an Atom... Where to start?

Post by jonb » Wed Mar 20, 2013 6:51 pm

I've just won an Atom on eBay. Expensively, I might add, but there it is, they are in demand.

Now, this one has no power supply, cables or manuals.

So first off, what is the power requirement? I read on another thread that 5v at 4A would suffice. It appears to have 12k of RAM and no other extensions.

So questions:

How to get a video signal from it?
Has anyone got a copy of the programming manual they want to sell?
Any recommendations for reasonably off the shelf power supplies?
Are the floating point ROMs and other extensions easy to come by?
What opportunities exist to expand it? Ad how much do they tend to cost?

Obviously my first task is to get it working....


This should be fun!

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Re: Got myself an Atom... Where to start?

Post by Prime » Wed Mar 20, 2013 7:29 pm

jonb wrote:I've just won an Atom on eBay. Expensively, I might add, but there it is, they are in demand.

So questions:

How to get a video signal from it?
Pins 9 and 10 of PL4 are mono composite video.
Has anyone got a copy of the programming manual they want to sell?
Any recommendations for reasonably off the shelf power supplies?
I use these : http://www.rapidonline.com/Electrical-P ... up-85-2940

Is it This : http://www.ebay.co.uk/itm/330887118709 one ?

Looks like from the picture it has the FP ROM, You can add a printer port by adding the socket, and the 6522. I believe that SirMorris still has some of his excellent AtoMMC MMC storage modules available.

Alas I have just sold the last of the current run of my RAM/ROM and Colour boards. Not sure if/when I'll do another run, depends on interest I suppose.

Cheers.

Phill.

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Re: Got myself an Atom... Where to start?

Post by jonb » Wed Mar 20, 2013 8:59 pm

Yes, that one. Hope the price wasn't too silly! I thought the fp rom went into the socket to the right of the black wire..? Be good if it does have it, but hardly a deal breaker. However I don't know if it actually works! I will be interested in expansions and especially the MMC (I've got one on the BBC Turbo MMC which is pretty brilliant... Are they compatible I wonder?).

It should be here by the weekend!

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Re: Got myself an Atom... Where to start?

Post by danielj » Wed Mar 20, 2013 9:09 pm

It's a different piece of kit to the beeb one. You need to get in touch with SirMorris!

d.

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Re: Got myself an Atom... Where to start?

Post by jonb » Wed Mar 20, 2013 9:43 pm

Errr... Who?

iainjh
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Re: Got myself an Atom... Where to start?

Post by iainjh » Wed Mar 20, 2013 11:19 pm

Hi

see my pm for some extra info, but a quick note on atom psu's as the guys here have already been so helpful to me when I asked the same questions!

Note the atom requires, as standard, an odd voltage and has to have a few links added to make it run with 5v. Have to be very careful to get that, the amperage and the polarity correct! Search sth for "5v psu atom" and you'll turn up some details. Also the standard socket was an odd size (not 2.1mm), if your 1st search hasn't found that search "2.1mm atom" on sth and you'll turn up a post or two about using a part from maplin that will "just about do".

One last note, my atom didnt work due to multiple points of failure but there's not much on the board and there always seems to be a way to fix it.

have fun with it!

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Re: Got myself an Atom... Where to start?

Post by 1024MAK » Thu Mar 21, 2013 1:46 am

jonb wrote:Errr... Who?
SirMorris

Mark

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oss003
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Re: Got myself an Atom... Where to start?

Post by oss003 » Thu Mar 21, 2013 8:07 am

Hi jonb,

here's a checklist to getting started:

1. Start with minimal configuration:

Code: Select all

RAM:
- Install IC's 51,52,10,11 (#0000-#03FF, #2800-#2BFF)
- Remove 2114's IC 12-19(#2C00-#3BFF)

VIDEO:
- Install IC's 42,43 (#8000-#83FF)
- Remove IC's 32-41 (#8400-#97FF)

ROM:
- Install IC 20 (#C000-#CFFF,#F000-#FFFF)
- Remove IC21,24 (Floating point #D000-#DFFF, Utility ROM #A000-#AFFF)

I/O:
- Remove IC 1,2,3,4 (VIA + buffers)
- Remove IC 50, (printer buffer)
- Remove grey wire (probably printer bit7)
2. Check VDG output:

Code: Select all

- Try pin 9/10 PL4 (composite video on monitor)
- Try SK1 (UHF modulator on TV) 
3. Check signals:

Code: Select all

- Check power supply is between 4,95 and 5,05V
- Check if 5V is present on PL6/7 (pin1 and 32)
- Check RST signal by pressing BRK-key (pin4 IC9 should go to 0V)
- Check RST signal by pressing BRK-key (pin35 IC25 should go to +5V)
- Check the 1 mHz signal with a scope on pin 37 IC 22 (6502)
- Check the 3.58 mHz signal with a scope on pin 33 IC 31 (6847)
- Check PHI2 on pin1 IC 9 and pin 6 IC9 with scope (6502)
- Check NRDS (pin 9 IC49)
- Check NWDS (pin 10 IC49)
- Check if RST, PHI2, NRDS and NWDS, +5V is measured on all chips
4. Check re-soldered spots

Code: Select all

- Check if there are no shortcuts or pins soldered together
- The best way is to remove the old solder and solder the pins again
5. Check the IC's:

Code: Select all

-  Try to exchange the 6847, 8255 or 6502
If this doesn't work then you have to trace the signals to find out where the problem lies.

Greetings
Kees


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jonb
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Re: Got myself an Atom... Where to start?

Post by jonb » Thu Mar 21, 2013 6:50 pm

Thanks Martin.

Good God, I do hope none of they keys are broken (although I do know the CTRL key is wonky, might have been glued!

If you read the item description you can see it is not tested, as the seller doesn't have the power supply or cables to test with. So I have taken a big chance, knowing that it should be reasonably easy to resurrect it if it really is a goner.

I just hope I don't have to take the keyboard apart..... :shock:

Good idea with those Ethernet cable insulators, mind. Doubt I have the patience!!

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Re: Got myself an Atom... Where to start?

Post by martinw » Thu Mar 21, 2013 8:05 pm

Not a problem, good luck with yours :)

Martin

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Re: Got myself an Atom... Where to start?

Post by jonb » Sat Mar 23, 2013 1:28 pm

OK. First job was a wash & brush up. Keys and upper case came up nice, but the lower case is yellowed in places. Not a big deal, really, it looks very nice otherwise.

It's an Issue 4 board. I've modded it for 5v per the technical manual and hard wired a switched mode supply (5v 3A should keep me going...). Also wired a trailing coaxial cable to PL4 for the video signal. Plugged it in, and all is well. Got the MMC on order from Charlie and I am nearly ready to go.

I need a proper power plug (I'm going to read up on that) and I would like to fit a video socket. What's the best way to do that? I've seen case mounted BNC sockets before but I am not sure I want to be hacking the case about. Maybe I should fit a better PL4 socket, as it is currently just a set of upright pins, and I imagine there is a plug you can get so it is accessible from the back of the machine. Any ideas?

How do I tell if the FP rom is there? Try and do some math? And, does it have any OS type *COMMANDS like the Beeb? I could not see anything in the (online scanned) manual and *HELP gave a COM? error.

Incidentally, the manual I read talks about the COPY key and arrows, which look to be just like a Beeb or Elk in use. It doesn't work, am I missing something? Cursor does move properly, and the copy key advances it, but it does not actually copy the character it has advanced over.

Finally, I tried some of the graphics modes. CLEAR 1 for example. The result is a screen with a blurred, skewed top. What might the problem be? It's the same in all modes apart from 0. Typing L. gives a line of garbled stuff. It is obviously printing the text but hard coded to mode 0!

Cheers

JonB

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Re: Got myself an Atom... Where to start?

Post by oss003 » Sat Mar 23, 2013 7:31 pm

Hi jonb
jonb wrote:How do I tell if the FP rom is there? Try and do some math? And, does it have any OS type *COMMANDS like the Beeb? I could not see anything in the (online scanned) manual and *HELP gave a COM? error.
Wished it worked like that but hé ...... it's an Atom ;-)
You can try some Floating Point commands like FPRINT 4/5 or FPRINT SIN(3.14)
Just check the commands in chapter 22 of Atomic Theory and Practice
http://www.acornatom.nl/atom_handleidin ... 3.html#163
jonb wrote:Incidentally, the manual I read talks about the COPY key and arrows, which look to be just like a Beeb or Elk in use. It doesn't work, am I missing something? Cursor does move properly, and the copy key advances it, but it does not actually copy the character it has advanced over.
Wished it worked like that but hé ...... it's an Atom ;-)
The cursor keys are working like this:

Code: Select all

CURSOR left/right         = move 1 position to the right
SHIFT + CURSOR left/right = move 1 position to the left
CURSOR up/down            = move 1 position up
SHIFT + CURSOR left/right = move 1 position down
COPY                      = copy character under the cursor into input buffer
jonb wrote:Finally, I tried some of the graphics modes. CLEAR 1 for example. The result is a screen with a blurred, skewed top. What might the problem be? It's the same in all modes apart from 0.
Wished it worked like that but hé ...... it's an Atom ;-)
Sounds like a video circuit- or monitor problem. Can you upload a screen image?
CLEAR 0 is text mode (black border) and CLEAR 1,2,3 and 4 are graphic modes (white border).
jonb wrote:Typing L. gives a line of garbled stuff. It is obviously printing the text but hard coded to mode 0!
Wished it worked like that but hé ...... it's an Atom ;-)
Typing L. lists the current program. If there's no program in memory, it's possible to display rubbish. After a BREAK, you must type OLD and then LIST to list the program. Type:

FOR I=32 TO 255;PRINT $I;NEXT

to display all characters.

Greetings
Kees

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Re: Got myself an Atom... Where to start?

Post by jonb » Sun Mar 24, 2013 12:35 pm

"Copy character under the cursor to the input buffer"

What does that mean if it doesn't mean "copy like BBC micro"? In other words, how do you get the stuff out of the input buffer into a line of BASIC? Or put another way, how do I edit a line of BASIC without having to type it all over again?

About modes other than zero - I think this means that you cannot PRINT in those modes, because the ROM's character output routine is hard coded for mode zero. Meaning by that, the memory format is different (more lines and columns) but the text output routine still thinks it is Mode 0. At least, that is what it looks like to me.
Wished it worked like that but hé ...... it's an Atom ;)
Is there an echo in here...? :D

Meanwhile, I have been to Maplin (oh God the things we do for love!) and scored a power plug. The one that fitted turned out to be 2.5mm / 5mm, although I have not yet wired it up so I don't know how good a connection it will give.


Thanks

JonB

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Re: Got myself an Atom... Where to start?

Post by Prime » Sun Mar 24, 2013 1:31 pm

jonb wrote:"
About modes other than zero - I think this means that you cannot PRINT in those modes, because the ROM's character output routine is hard coded for mode zero. Meaning by that, the memory format is different (more lines and columns) but the text output routine still thinks it is Mode 0. At least, that is what it looks like to me.
That's partly true, the 6847 has basically 2 modes of operation character mode which uses a character rom built into the 6847 to produce the familiar 32x16 text mode screen, this is mode 0. This mode only uses 512 bytes of memory, as each character only uses 1 byte.

It also has various bit mapped graphics modes up to 256x192, these are modes 1,2,3 & 4. These modes use up to 6K of memory as they use either 1 or 2 bits per pixel.

The Atom ROM only has support for printing characters in mode 0, it's quite possible to write routines to output text in the other modes, it's just not supported by the ROM. This is actually quite common for machines using the 6847, e.g. the Dragon 32/64, Tandy CoCo 1/2/MC10.

Cheers.

Phill.

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Re: Got myself an Atom... Where to start?

Post by oss003 » Sun Mar 24, 2013 1:49 pm

jonb wrote:"Copy character under the cursor to the input buffer"

What does that mean if it doesn't mean "copy like BBC micro"? In other words, how do you get the stuff out of the input buffer into a line of BASIC? Or put another way, how do I edit a line of BASIC without having to type it all over again?
Everything you type is copied into the input buffer at #0100. If you press ENTER, the input buffer is executed. So the COPY key copies the character into the input buffer but that is not visible on the screen.

Greetings
Kees

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jonb
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Re: Got myself an Atom... Where to start?

Post by jonb » Sun Mar 24, 2013 5:12 pm

Ok, I will try it. Doesn't sound like it is useful for editing basic though, unless one is very clever about it.

So, now I have a proper power lead, a tape lead and a flying video lead which is plugged into PL4 (not soldered).
image.jpg
image.jpg (1.32 MiB) Viewed 1035 times
It begins to look like a real early 80s setup!
image.jpg
image.jpg (1.03 MiB) Viewed 1035 times
But I am still having graphic mode problems..
image.jpg
image.jpg (956.73 KiB) Viewed 1035 times
I imagine a capacitor has stopped doing its job as well. Where should I start here? It's composite video.

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Re: Got myself an Atom... Where to start?

Post by danielj » Sun Mar 24, 2013 5:32 pm

In all honesty, I'd just replace all the electrolytics on the board - CPC are free on all orders at the moment, so just whack one in there.

7x22uf axial, 10V - order code CA07190 (Minimum order 5)
1x10uf axial, 25V - order code CA07171 (Minimum order 5)

d.

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jonb
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Re: Got myself an Atom... Where to start?

Post by jonb » Sun Mar 24, 2013 5:34 pm

Happy to report it DOES have the FP rom. Whoo hoo!

Funny, I expected to see an EEPROM but it looks like any other plastic DIL chip. But what this means is that I still have a spare socket (I guess this is where the programmer's toolkit should go).

It's all a bit moot though, because I have asked Prime for a ROM RAM card, and I have the MMC thingie on order with Charlie.

Happy days!

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Re: Got myself an Atom... Where to start?

Post by oss003 » Sun Mar 24, 2013 6:05 pm

Looks like a sync problem, have a look at The Corfiot's solution on Ian's Atom.

http://www.stardot.org.uk/forums/viewto ... 5&start=30

The best way is to replace all capacitors like Daniel mentioned.

Greetings
Kees
TheCorfiot wrote:I thought Iain may appreciate an update..

Replaced Q1, transistor in video circuit...
Caps also replaced as they were reading way out too.
Awaiting delivery of low profile 3.58 and 4.0 MHz crystals...

Now to try and find some instructions on installing and using the AtomMMC.

Thanks all.

TC :D

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Re: Got myself an Atom... Where to start?

Post by TheCorfiot » Sun Mar 24, 2013 6:33 pm

Hi jonb

Excellent stuff with the Atom, you will love the 2 addons you have ordered...

Can I please ask you to post up the part number from maplin of the dc power socket you fitted please for Iain's atom.
Getting one to fit on the board is not an issue on the ones I have tried but access when the lid is fitted is impossible.

Thanks in advance....

Regarding your video problem, replace the caps in the video output circuit, according to the atom technical manual any value polarised electrolytic cap between 10 to 47 microfarads at 10v will suffice.

TC

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Re: Got myself an Atom... Where to start?

Post by jonb » Sun Mar 24, 2013 7:04 pm

TheCorfiot wrote:Can I please ask you to post up the part number from maplin of the dc power socket you fitted please for Iain's atom.
Getting one to fit on the board is not an issue on the ones I have tried but access when the lid is fitted is impossible.
Happily!

Maplin DC Power Plug 2.5mm / 5.0mm. Code: L49AY - £1.69, the rip-off merchants!

My Atom shows signs of "shaving" around the ports. Nothing major, but enough to make a difference if connectors are tight. The Maplin plug has a screw on plastic shroud which is hexagonal in cross section; it could be that having flat sides is helping here. If you find it doesn't fit, you can always do away with the shroud and fit heat shrink tubing in its place. Naturally put some insulation on the +ve connection to prevent shorts, and you can shave away at the base of the plug too, if it's that tight. The plastic is slightly soft, so you can use a craft knife.

Also.. It does sound like various sockets were fitted, so this one might be no use for yours. Take the Atom to Maplin and try them out, they have quite a range of overpriced plugs in there.

Another idea that occurs is to desolder the plug and refit it with a spacer so it is a little bit away from the board. This, too, might help, as looking at mine I can see it is tighter against the top cover than the base (the board is screwed to the top cover, as you probably know).

Cheers

JonB

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Re: Got myself an Atom... Where to start?

Post by iainjh » Sun Mar 24, 2013 8:13 pm

Jon, I bought the same plug (did you see my pm?) and that was useful for me to a degree, as it only barely makes inside the 'original' socket.

it's the motherboard socket that's knackered on my atom and proving difficult to locate.

Maplin's do a 2.1mm board socket but the legs dont line up well with the holes on the board.

Anyone seen sphilmainwaring recently? :)

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Re: Got myself an Atom... Where to start?

Post by jonb » Sun Mar 24, 2013 9:53 pm

iainjh wrote:Jon, I bought the same plug (did you see my pm?) and that was useful for me to a degree, as it only barely makes inside the 'original' socket.

it's the motherboard socket that's knackered on my atom and proving difficult to locate.

Maplin's do a 2.1mm board socket but the legs dont line up well with the holes on the board.

Anyone seen sphilmainwaring recently? :)
Sure Iain, I read your PM and was grateful for it. In it, you mentioned a 2.1mm plug which I tried in mine and it doesn't fit. That's why I said it is 2.5mm, but I also said that I'd read there were different sockets.

What's the matter with yours? Loose? Or physically broken (cracked, etc). Maybe the -ve contact is bent back too far? Can you pull it out? I considered using a tooth scraper to do this on mine (it's a hooked tool with a pin- like tip that might be able to reach inside the plug). But it wasn't necessary in the end. Like I say, take the Atom to Mappers and do a bit of trial and error in their "plug" aisle, you never know!

For my part, 2.5mm is spot on, and I can even feel a slight click as it is pushed all the way in. I even tested it with a meter and there was no break of connectivity when wiggled.

Of course... "your mileage may vary", but it is worth a punt, surely? I understand you must be quite frustrated by the whole thing but I am sure you will sort it eventually. Good luck!

Cheers

JonB

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Re: Got myself an Atom... Where to start?

Post by jonb » Sun Mar 24, 2013 10:04 pm

Ah, I see, your power socket is cracked.. no plug is going to give you a good connection. If you cannot find something to replace it with, fit a flying lead for now.

By the way.. I read your thread and it looks to me like you have a very nice setup there!

:wink:


Me, I'm still struggling with a cassette deck!

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Re: Got myself an Atom... Where to start?

Post by jonb » Tue Mar 26, 2013 9:15 pm

danielj wrote:In all honesty, I'd just replace all the electrolytics on the board - CPC are free on all orders at the moment, so just whack one in there.

7x22uf axial, 10V - order code CA07190 (Minimum order 5)
1x10uf axial, 25V - order code CA07171 (Minimum order 5)

d.
They might have free delivery but they want a handling charge of £5.95 on an order of £3.80, and that's plus VAT.

WTF??! :evil:

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Re: Got myself an Atom... Where to start?

Post by Garrettimus » Tue Mar 26, 2013 9:48 pm

I want to by an Atom too, it's the only Acorn machine I don't have (OK, I don't have all the Master variations either). How easy is it to buy the AtomMMC? What about games?

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Re: Got myself an Atom... Where to start?

Post by danielj » Tue Mar 26, 2013 10:08 pm

jonb wrote:
danielj wrote:In all honesty, I'd just replace all the electrolytics on the board - CPC are free on all orders at the moment, so just whack one in there.

7x22uf axial, 10V - order code CA07190 (Minimum order 5)
1x10uf axial, 25V - order code CA07171 (Minimum order 5)

d.
They might have free delivery but they want a handling charge of £5.95 on an order of £3.80, and that's plus VAT.

WTF??! :evil:
No!
Type "WEBFREE" in the "comments" box for the order... They'll subtract the £6 when you're invoiced (it won't look like it at the time, but it does get taken off and you never get charged it).

http://cpc.farnell.com/jsp/bespoke/besp ... ebfree.jsp

d.

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Re: Got myself an Atom... Where to start?

Post by danielj » Tue Mar 26, 2013 10:10 pm

Garrettimus wrote:I want to by an Atom too, it's the only Acorn machine I don't have (OK, I don't have all the Master variations either). How easy is it to buy the AtomMMC? What about games?
If Charlie (SirMorris on here) has any, very easy. Games, I think there was a big list of all atom games knocking around somewhere...

d.

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Re: Got myself an Atom... Where to start?

Post by jonb » Tue Mar 26, 2013 10:11 pm

Forum user sirmorris makes the MMC card, you can PM him for details of availability. I've not got mine yet but I read lots of good comments. Once you have it I imagine loading games is just a matter of preparing an SD card and copying game images to it for loading on the Atom.

I am sure others with experience will chip in here, at least I hope so, because right now I don't actually know how to use it! :oops:

Edit: Ah! Dan beat me to it! :)

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