Search found 196 matches

by waltermixxx
Thu Jan 18, 2018 5:44 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

they do their initial blinking on power up.
Pretty sure that is the only time they blink unless there is disk access.
pretty sure it does not blink at the 12 second mark when the heading on the tv changes from Acorn Atom to Acorn Atom + ATOMMC2

I will do more testing. :)
by waltermixxx
Thu Jan 18, 2018 11:35 am
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

I will have to check. It did this with two separate power supplies. Both at least 2.amp. Both are from name brand devices. The output with no load was about 5.25. I have a Rigol DSO scope, so I can watch the NMI line. The light on the device does flash upon power up. I could try issuing a link comma...
by waltermixxx
Wed Jan 17, 2018 11:24 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Here is a link to the youtube video.
hopefully it shows the issue...

https://www.youtube.com/watch?v=zzgItXsn9x0

no laughing at my commentary ;o)
by waltermixxx
Wed Jan 17, 2018 8:50 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Will do. :)
by waltermixxx
Wed Jan 17, 2018 8:21 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

before I installed the 32k daughter card, no scrambled screen on power up. and i got the Acorn Atom + ATOMMC right away. WIth the 32k ram daughter card I built, still no scrambled screen, just Acorn Atom at the top, with a cursor... and If I do a shift break before 12 seconds have past, I still only...
by waltermixxx
Wed Jan 17, 2018 6:29 am
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Regarding the 32k memory upgrade, I notice when I turn my Atom on, the screen says Acorn Atom initially, then after about 12 seconds, it changes to Acorn Atom + AtoMMC

Is that delay normal because of the extra ram?
by waltermixxx
Fri Jan 12, 2018 8:07 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Yup saw this: One final note, is that different manufacturers LS/HC/HCT 123 chips have slightly different time constants, and the R and C values have to be calculated from the datasheet of the chip you are using. Cheers. Phill. noisekiller.jpg I know there is a ball park R (8.2k) / C (150pf) to valu...
by waltermixxx
Fri Jan 12, 2018 6:00 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Nice job Walter ..... let the gaming begin ..... =D> The easiest way to add a noisekiller is this one: http://www.acornatom.nl/atom_nieuws/1985/nr3/19853086.htm It also replaces the video buffers with more common 74LS244 and 74LS245 chips. Greetings Kees I was thinking of going this route, once aga...
by waltermixxx
Fri Jan 12, 2018 3:20 am
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Ok the 32k ram daughtercard is done. :) seems to work fine. 38933202664_d3e30850e9_k.jpg 39641677201_02e630862d_k.jpg 38745358965_a49c04c043_k.jpg Wondering if Colour board should be next, or noise eliminator... I'm thinking noise eliminator, as I dont think I ever used colour as a kid with the atom...
by waltermixxx
Tue Jan 09, 2018 3:50 am
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Ok progress thus far. 8 address lines and a couple of CS lines to go. I know I'm drawing this out, (This thread, and this little project). But just like a good book, a good little wiring project makes me sad as I near the end. The book because I will miss the characters, and the little wiring projec...
by waltermixxx
Mon Jan 08, 2018 10:03 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Once again. Thank you.

:0)
by waltermixxx
Mon Jan 08, 2018 9:10 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Ok perhaps a goofy question, and perhaps I should have asked before starting to build my very basic 32k ram daughter card. :) I've looked in the Technical Manual, and even Splitting the Atom documentation, and I guess I'm wondering: Once I install the 32K memory and have memory from #0000 to #7FFF, ...
by waltermixxx
Mon Jan 08, 2018 7:20 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Thank you Dave,

Very much appreciated. :)

Cheers. :)
by waltermixxx
Mon Jan 08, 2018 1:06 am
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

I noticed that there were two inverters on pin 39 of the PHI2 pin. Is that used to add a propagation delay or just buffer it (without inverting it)? Would this be ok for my 32k ram upgrade, (this is from Briel's Apple 1 replica) : 32kram.png could i use this as is, or should i add two inverters to t...
by waltermixxx
Sun Jan 07, 2018 11:39 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Because of the vero board I had on hand was only one sided. There was no way to solder the header to the daughter card board to ensure a good solid connection to the Atom. I basically did it with what I had on hand. The 6502 is a spare, i have a few (and it's still working fine) :) The 32kB static r...
by waltermixxx
Sun Jan 07, 2018 10:15 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

I left room for a 16 pin chip :) just incase. :) (14 pin plus decoupling cap...) I will also add them on the daughter card for the cpu and ram chip :)

so I will add a 74LS00 :) Thank you :)
by waltermixxx
Sun Jan 07, 2018 7:58 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

I replaced the IC24 #A000 Rom socket with a nice machined socket, and I replaced the IC6 74LS138 socket as well, also machined. I installed a proper RCA jack for the Composite Monochrome video output. I also began work on my 32K ram CPU socket ram board. Because it's the first 32k of ram I figure I ...
by waltermixxx
Sat Jan 06, 2018 3:15 pm
Forum: acorn atom
Topic: Prime's ROM/RAM board
Replies: 15
Views: 1340

Re: Prime's ROM/RAM board

I too would like to register interest in a ram/rom board, if not too late.
I also have an AtoMMC interface.

Cheers. :0)
by waltermixxx
Thu Jan 04, 2018 10:37 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Technically an OLD Acorn Atom user.... my first one in 1982 or so. :) and I'm old.... :)

and thanks for the welcome, as it's been a very long time, I may as well be a new user. :)

Cheers.
by waltermixxx
Thu Jan 04, 2018 6:53 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

And it looks better now that I've got the memory sorted out. All 15k accounted for. Thanks guys for your help. I am truly chuffed!! I swapped the ram around after checking the connection from pin 12 of IC6 to pin 8 of IC12/13. The connection was good so a swap was required. I guess reseating them as...
by waltermixxx
Wed Jan 03, 2018 1:54 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

Re: My New Acorn Atom :)

Cool, Thank you. I will try and swap ram, and definitely replace that socket. I am so happy with this Atom, it brings back so many memories. (At least 12k of memories...he he he). I even bought a 5"black and white tv just for the experience. Thanks again Roland, my wife thanks you as well, as I...
by waltermixxx
Tue Jan 02, 2018 10:43 pm
Forum: acorn atom
Topic: My New Acorn Atom :)
Replies: 39
Views: 933

My New Acorn Atom :)

So my atom arrived (Thanks again, Roland!!! :0) ), and it seems to work, but it was definitely jostled on its month long trip to me. A few loose chips, and a couple that jumped out of their sockets... easy fix. :) here she is in all her glory: Atom.jpg IMG_1160.JPG I have installed AtoMMC interface ...
by waltermixxx
Sun Dec 24, 2017 4:11 pm
Forum: acorn atom
Topic: Happy Holidays! :)
Replies: 2
Views: 257

Happy Holidays! :)

Best Wishes to all :)

And a quick thank you to all the folks supporting and inquiring about all things Acorn Atom! Once again Happy Holidays, a Very Merry Christmas, and an exceedingly Happy New Year!! :)

Cheers!!
by waltermixxx
Tue Dec 12, 2017 3:17 pm
Forum: acorn atom
Topic: NTSC Colour board. :)
Replies: 9
Views: 353

Re: NTSC Colour board. :)

Me again :) I have a question, as you can see above, (scroll up a few posts to the picture of my Acorn Atom Motherboard.) i have 8k of ram connected in the "video ram" section of the Atom board. :) I know that normally the MC6847 can use up to 6K of ram #8000-97FF. because there is 8k i su...
by waltermixxx
Fri Dec 08, 2017 11:58 pm
Forum: acorn atom
Topic: NTSC Colour board. :)
Replies: 9
Views: 353

Re: NTSC Colour board. :)

thank you... :) lots of good info in that document. :) Cheers. :) the 74LS573 looks like a nice fit, along with the 74LS123. :) i have lots of stuff to do to my atom: 32k RAM upgrade (deadbug on my 6502) 0000-7FFF and remove existing ram chips (unless I get lucky enough to get on the list of folks w...
by waltermixxx
Fri Dec 08, 2017 8:54 pm
Forum: acorn atom
Topic: NTSC Colour board. :)
Replies: 9
Views: 353

Re: NTSC Colour board. :)

A question about "snow or noise on the screen" when playing games, on a real Acorn Atom, with 6k of Video ram: will this happen in black and white as well as colour games? If I understand correctly the snow is from a timing issue caused when the cpu and the MC6847 are accessing video ram a...
by waltermixxx
Tue Dec 05, 2017 8:41 pm
Forum: acorn atom
Topic: NTSC Colour board. :)
Replies: 9
Views: 353

Re: NTSC Colour board. :)

its a newer version of it. it looks like... :) I will let folks know how it works out. I sent a note to Ed, (Zippster) and he confirmed the board does come with the MC6847 and MC1372. I purchased the board and will update the thread and post pictures of the Atom when it arrives, with the colourboard...
by waltermixxx
Tue Dec 05, 2017 6:45 pm
Forum: acorn atom
Topic: NTSC Colour board. :)
Replies: 9
Views: 353

Re: NTSC Colour board. :)

Zippster, a guy in the U.S. builds lots of very cool projects for the Tandy Colour Computer.
I'm looking to purchase one of these from him, it's designed for the CoCo 2.

I just have to double check with him if the 1372 is included. :)

20171203_092724.jpeg


20171203_092654.jpeg
by waltermixxx
Tue Dec 05, 2017 6:28 pm
Forum: acorn atom
Topic: need Acorn Atom expert
Replies: 6
Views: 284

Re: need Acorn Atom expert

Once I get my Acorn Atom, (I have one coming to me from the Netherlands) I would be happy to record some fond memories of using my Acorn Atom, but I have to be honest, I'm the odd man out, in that these were much more popular in the U.K. and I don't think I knew anyone who had an Acorn Atom buy myse...
by waltermixxx
Sat Dec 02, 2017 6:37 pm
Forum: acorn atom
Topic: I've got an Acorn Atom... Woot Woot :) (changed title (again) :)
Replies: 23
Views: 840

Re: I've got an Acorn Atom... Woot Woot :) (changed title (again) :)

No that doesn't work because the AtoMMC rom and DISATOM are both #Axxx versions. You could install an #Exxx AtoMMC rom instead of a #Axxx version and place the AtoMMC rom on top. But if he did that wouldn't it preclude the use of SDDOS which IIRC is an $E000 ROM? I do have some RAMROM boards left, ...

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