iRAM/640 - Ram Expansion - public repository

eto · 00:00, 30 January 25

As always promised I just have published the iRAM/640 repository with the Gerbers and JED files for the GALs, so now everybody can start building the expansion:

https://github.com/etomuc/CPC6128_iRAM-640

The documentation is still minimal and will be improved if necessary. For any questions or required clarifications please use this thread here.

d_kef · 08:48, 30 January 25

Thanks a lot for that.
It seems to be the perfect new year gift for my 6128.

d_kef

McArti0 · 09:25, 30 January 25

And PCBway...

dodogildo · 09:30, 30 January 25

Excellent service for the CPC community. Can't wait to try building it coming weeks!

Prodatron · 19:17, 30 January 25

Now I wonder if someone would like to build a batch, I would buy one or two more for sure.

McArti0 · 07:27, 31 January 25

What is the cheapest way to program ATF16v8?

TLL866II-PLUS with new Firmware 12.xx cost ~50$

Can it be cheaper?

Rabs · 07:30, 31 January 25

Quote from: eto on 00:00, 30 January 25As always promised I just have published the iRAM/640 repository with the Gerbers and JED files for the GALs, so now everybody can start building the expansion:

https://github.com/etomuc/CPC6128_iRAM-640

The documentation is still minimal and will be improved if necessary. For any questions or required clarifications please use this thread here.

Excellent work, thanks. I have some PCBs on order.

dodogildo · 12:37, 31 January 25

Are the instructions on the repository still relevant, in light of current discussions in the main thread?

McArti0 · 13:09, 31 January 25

Now main tread is about ext for cpc464.

eto · 14:38, 31 January 25

Quote from: dodogildo on 12:37, 31 January 25Are the instructions on the repository still relevant, in light of current discussions in the main thread?

The other thread is about the ongoing development - currently it's about the edition for the 464 and 664.

Rabs · 22:54, 13 February 25

@eto is there any reason why you did not socket all the ICs. Just wondered before I start to build.

eto · 23:18, 13 February 25

Quote from: Rabs on 22:54, 13 February 25@eto is there any reason why you did not socket all the ICs. Just wondered before I start to build.

The reason is space. It's a tight fit in the 6128 and with a socket the keyboard casing might touch the ICs and put pressure on the expansion. For the CPU I could move the socket just far enough so it will be behind the keyboard.

I'm not 100% sure any more if it's really impossible to use sockets as Prodatron mentioned that he could even fit the expansion under the metal shield of a German 6128 and I was convinced that it would not fit.

Rabs · 17:17, 14 February 25

@eto just checking the GitHub repository lists 22uF in the BOM but the silk screen has 10uf. Guess it does not really matter.

Rabs · 18:01, 14 February 25

@eto all working. Great thanks. I did socket the ICs on my first go, just to make sure I got the PALs programmed ok but as you suggested it does not quite fit. Will do the next one as per your instructions.

Great GitHub repository. Many thanks for the hard work and sharing.

eto · 10:35, 15 February 25

Quote from: Rabs on 18:01, 14 February 25@eto all working. Great thanks. I did socket the ICs on my first go, just to make sure I got the PALs programmed ok but as you suggested it does not quite fit. Will do the next one as per your instructions.

Great GitHub repository. Many thanks for the hard work and sharing.

AWESOME! Thanks for your feedback.

I'll add the information that it's a good idea to have one PCB with sockets to test the PAL programming. I also did that.

GUNHED · 16:36, 16 February 25

Quote from: Prodatron on 19:17, 30 January 25Now I wonder if someone would like to build a batch, I would buy one or two more for sure.

And I would like to buy two of them too. Bigger batch, smaller price.

Rabs · 22:06, 19 February 25

@eto all done as per your instructions and fits under the keyboard nicely.

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Rabs · 22:15, 19 February 25

The only dilemma I had was what type of pin header to use. Standard pin headers seemed a bit thick. In the end I used Samtec TS-120-T-A.

They have a thinner and smaller insertion pin when compared to standard header pins but you have to be very careful when inserting into the original Z80 socket. In the end, I removed the main PCB from the case to make sure I aligned the pins correctly.

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Prodatron · 00:48, 20 February 25

Quote from: Rabs on 22:06, 19 February 25@eto all done as per your instructions and fits under the keyboard nicely.

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What a clean CPC!
I just love the iRam640.

d_kef · 15:22, 21 February 25

Another happy customer

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d_kef

Rabs · 15:35, 21 February 25

Need a nice badge for the case now. My sticky label does not do it justice

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eto · 16:10, 21 February 25

You need a new badge that says "Amstrad 640k Colour Personal Computer" ;-)

Maybe Badge Man can do that: https://www.retro8bitshop.com/

McArti0 · 17:56, 21 February 25

https://www.cpcwiki.eu/forum/hardware-related/wip-internal-512k-expansion/msg242825/#msg242825

https://www.cpcwiki.eu/forum/hardware-related/wip-internal-512k-expansion/msg242898/#msg242898

McArti0 · 18:03, 21 February 25

@Rabs and @d_kef ! You have 120ns ram from new.

d_kef · 19:05, 21 February 25

Quote from: McArti0 on 18:03, 21 February 25@Rabs and @d_kef ! You have 120ns ram from new.

I've seen 2 or 3 v2 6128 motherboards in the past and all of them had 120ns RAM chips.

d_kef

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iRAM/640 - Ram Expansion - public repository