PSION Organiser II Forum

I’m starting to have a go at the hardware side of things, (definitely inspired by Andrew) so I have laid out a 32k RAMPAK on breadboard. I deliberately went with the DIP equivalents to make it easier to wire. It’s been a long time since I’ve used breadboard, started all neat, then address and data lines are strewn all over the place!

I only made one tiny mistake, I omitted a link from the positive busbar on one side to the other. Link in; and it SIZED the pack and is working perfectly. I’ve omitted the battery, but interestingly when monitoring the supply from the PSION - 4.5V - if I remove the PSION battery, it takes a long time for the voltage to decay. Even getting down to 1.5V, the HM62256 held its memory.

I'm always amazed by you electronics chaps that can do this stuff... I watched Olivier make his 256K Rampack, I bought one, best purchase I ever made for the Organiser (except perhaps the USB Comms Link!) I wish I had bought two.... Hopefully Andrew might make some with his great battery holder!

I use one of my 32K rampacks as a development tool, it is great for testing pack images, it is quick to format and then MAKE the pack to. No waiting for the Datapak formatter every time you want to try an update.

For others watching... out of interest the Technical Reference Manual and Schematics are (here) ...

Sincerely Martin

PS Rampak or Rampack? the debate continues....

Zenerdiode wrote: ↑Sat Jan 21, 2023 1:58 am I’m starting to have a go at the hardware side of things, (definitely inspired by Andrew) so I have laid out a 32k RAMPAK on breadboard. I deliberately went with the DIP equivalents to make it easier to wire. It’s been a long time since I’ve used breadboard, started all neat, then address and data lines are strewn all over the place!

I only made one tiny mistake, I omitted a link from the positive busbar on one side to the other. Link in; and it SIZED the pack and is working perfectly. I’ve omitted the battery, but interestingly when monitoring the supply from the PSION - 4.5V - if I remove the PSION battery, it takes a long time for the voltage to decay. Even getting down to 1.5V, the HM62256 held its memory.

Excellent work! Are you going to try to squeeze it all down to a datapack size?

I'm a bit allergic to batteries due to them leaking and going flat, so I did attempt using MRAM and FRAM in a datapack. That, so far, hasn't workd (I revisited it a few times, still didn't get it working). One problem was that the chips are expensive (£40, I think, each, or so). To work on different types of chip I made a 'datapack breakout' board which accepts plug in daughter boards so that you can use different memory technology without having to redo the glue logic each time. So I have a RAM daughter board and FRAM and MRAM. I'm not sure if I did a video. I can make the KICAD files available if you are interested.

MRAM and FRAM would be nice, as they are non volatile storage with the speed of RAM. Tricky to interface, though. I got one of them working as a datapack at slower speed on my Arduino datapack tool but not in the organiser itself. I'll see if I have photos.
Hmm, looks like I did a video:

https://youtu.be/3DFUNjhNuWg

i haven't got a photo of the breakout to hand, here's a 3d view:
The daughter boards plug in on the right and there's a lot of jumpers to configure the glue logic. Here's the RAM board: I didn't add battery connections as i didn't think I'd need them but then found it's tricky testing a ram pack without powering it down, so added a battery on flying leads.

Andrew

Martin wrote: ↑Sat Jan 21, 2023 8:29 am I'm always amazed by you electronics chaps that can do this stuff... I watched Olivier make his 256K Rampack, I bought one, best purchase I ever made for the Organiser (except perhaps the USB Comms Link!) I wish I had bought two.... Hopefully Andrew might make some with his great battery holder!

I use one of my 32K rampacks as a development tool, it is great for testing pack images, it is quick to format and then MAKE the pack to. No waiting for the Datapak formatter every time you want to try an update.

For others watching... out of interest the Technical Reference Manual and Schematics are (here) ...

Sincerely Martin

PS Rampak or Rampack? the debate continues....

Well...

I do have some 256K RAM pack PCBs here. V1.0 and I'm fully expecting them not to work, but it's a start. The RAM chips haven't turned up yet so I've not built them up. I'm planning on using the battery modification PCBs to hold the batteries, but it depends on the mechanical arrangement as to whether it'll fit.

3D view:
Andrew

Andrew...

Amazing! I'm happy to test one when you're ready and when you think they are fit for purpose put my name on two..

Incredibly impressed
Martin

Martin wrote: ↑Tue Jan 24, 2023 11:23 am Andrew...

Amazing! I'm happy to test one when you're ready and when you think they are fit for purpose put my name on two..

Incredibly impressed
Martin

No problem. I just need to get the RAM chips and find the problems that are definitely there. probably...

Andrew

I'm in too! ... I had two 256K RamDrive a long time ago but I sold them 10 years ago and now I regret it.
Nice project!

Interested in the 256k Rampak too - I wonder if it will be as keen to lose its contents as the old 32k ones are, hopefully not

It is worth remembering that Rampacks are volatile, because any surge or disruption in power supply can result in losing all data, for example removing a Rampack whilst the organiser is switched on, or plugging a Comms Link in on a powered organiser. The main thing to remember is always BACK UP any important data before removing a Rampack. The problem of the battery running low is always going to be a problem, but at least having a replaceable battery makes it easier, and it is not a problem as long as any data is backed up.
There is nothing worse than seeing the dreaded “Sizing Pack....”, when you haven’t backed up the data from a Rampack.
I assume the 256k uses more battery power than the 32k, but I have never checked it out.

I remember never had any issues with my Rampacks in the old times, but I mostly used them for testing, running OPL pgm or just used them as a buffer sometime. But I'm agree, they are "volatile" (and perhaps static and fragile compared to an eprom of course), so a good backup is a main rule in any case