Read Only datapack
Posted: Sun Jan 29, 2023 9:56 am
I'm not sure if this is documented anywhere, I can't explicitly see anything:
While messing about doing things I accidentally erased a datapack which was an original Psion pack with a program on it. It was for the Psion 1 but I don't think that's important. No problem I thought, I'll just reprogram it. After several reprogramming attempts I failed to program the pack. After a flash of inspiration I checked the PCB and found that the VPP signal wasn't connected to the EPROM. So, even though it looks like a datapack and has most if not all of the same circuitry, it is not writeable. I didn't know that Psion did this, I assumed their programs were on normal datapacks with a write-protected bit in the header.
On the PCB: you can see that pin 1 just goes to 5V, not the VPP signal.
Anyway, maybe this is common knowledge, but I was surprised.
Andrew
While messing about doing things I accidentally erased a datapack which was an original Psion pack with a program on it. It was for the Psion 1 but I don't think that's important. No problem I thought, I'll just reprogram it. After several reprogramming attempts I failed to program the pack. After a flash of inspiration I checked the PCB and found that the VPP signal wasn't connected to the EPROM. So, even though it looks like a datapack and has most if not all of the same circuitry, it is not writeable. I didn't know that Psion did this, I assumed their programs were on normal datapacks with a write-protected bit in the header.
On the PCB: you can see that pin 1 just goes to 5V, not the VPP signal.
Anyway, maybe this is common knowledge, but I was surprised.
Andrew