Getting online with a 1987 Psion Organiser II

OK, I admit this project hasn't advanced very much recently as I've had quite a lot of other stuff to be getting on with. But I have been trying to make use of the Psion (in its standard form!) in my everyday life. Is it worth buying a Psion Organiser II for a few pounds off eBay in 2019 - if you don't intend to modify it? Well, here are a few uses for the device.

- It's a good, loud alarm clock. You can set 8 alarms up to a week in advance.

- The database is good for storing small amounts of information for short periods of time. I've used it to note down things like phone numbers and brief 'reminder' notes.

- Psion Tetris (see last log) is good fun for whiling away 10 idle minutes.

- You can buy a selection of Datapaks* containing original 1980s Organiser programs on eBay for £7.50 a pop. Things like word processors, the 'Travel Pack' and the 'Games Pack.' I haven't tried any of these but some of them could still be fun and/or useful.

Of course, if (unlike me) you own a fancy smartphone you can do all of these things at lightning speed in glorious Technicolor. But hey, that's what ordinary people do - and being ordinary is a bit of a waste of time.

As a final note - I have noticed recently that some modern (USB) Psion Comms Links have appeared on eBay for the not inconsiderable sum of £35 + postage. Realistically I think the Comms Link route is the only viable way to get the Psion (sort-of) online, so I am tempted to take the plunge. If I do, rest assured I'll witter on about it here...

The good news: I have managed to physically connect the Pi and Psion. I have also managed to send a simple 'signal' (literally 'pulses' i.e. single bits) from the Psion to the Pi's UART RX pin using SSCR* - but not the other way round. At least, not yet.

It turns out that reading and 'toggling' the pins in the Psion top slot isn't easy! As far as I know there is no simple command in OPL (the Organiser's built-in BASIC-esque high level programming language) that will let me set/read the state of the 3 general-purpose pins in the top slot. It looks like I will need to concoct some simple (?) machine code routines to toggle and read these pins. Until then, I have to stick to Organiser Tetris for my 8-bit entertainment...

Reading data from the Pi using SSCR would only be possible if I get hold of an 'official' Psion Organiser Comms Link, or something hardware compatible with this device. The Comms Link was the commercial name of the RS232-based device Psion produced in the '80s to allow the Organiser to communicate with the PCs of the time - back when PCs had serial ports and monochrome monitors. Psion Comms Links still pop up on eBay from time to time but they aren't cheap. A modern USB version has also been produced and sells for 20 Euros plus postage.

For now, though, I'm going to try and do without a Comms Link. Let's delve into the wonderful world of 1980s machine code...

*pedantic note:  the only pin I can toggle with SSCR is pin 2 on the top slot (SD0) which is not the pin I showed in the table in my last post!

So this week I've soldered the low-voltage side of the SparkFun converter board 'onto' the Raspberry Pi. I've let four long leads run freely from the high-voltage side of the board that can be pushed into the pins of the Psion top slot (breadboard-style!)

I've put the connections so far into a table. Now I need to put a fresh Raspbian Lite on the Pi and try to work out how to 'use' the Psion top slot. I believe it has 3 general purpose pins that can be read and written to using some kind of machine code. This page is proving very interesting https://www.jaapsch.net/psion/topslot.htm#p16.