STATS
Todays date:
Monday 20th of January 2025 11:25:03 AM
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Page last updated
18 December 2024
It's a Rodez
It's actually a Rodez V1.0 BBC User Port Switch.
Some people would refer to it as a 'Port Splitter' or 'Expansion Unit'. I add those quotes just for the search engines.
If you haven't read it already, see the previous page to learn how I came to own a BBC Micro in the first place.
I think the seller felt sorry for me, so he gave me a good price.
When I encountered the need for a User Port expansion, and had to design my own switch, we agreed to name it after him.
On EBay, his seller ID was Rodez.
Bare board
The new, unpopulated board.
With a connector of the correct size. See lower down the page.
Populated board
The board with all parts populated.
Two wire links beneath second chip. To prevent them flapping about I added some superglue.
Unfortunately, it spilled slightly, causing the greasy looking smear at bottom left.
I will not use that again.
Working board
Connected and working.
I could only find white LEDs for my quick test. Turns out they were ultra bright.
Out of habit I used a resistor for 3.3v supply. This circuit is 5 volts.
I need to adjust the resistor to bring the glare down a touch.
Mounted in the left socket is my Turbo MMFS card.
The right socket will contain my Concept Keyboard.
Now that I have the switch working, I can work on the Concept Keyboard code, test and save my work.
Without having to disconnect, re-connect.
Don't do what I did
Don't do what I did !!!.
I checked the circuit diagram over, and over.
I checked the PCB layout over and over.
If you look closely at the image, you will see that the connector will not fit.
I understood IDC type connectors were all the same size. They are not.
The one I chose from the parts list on the schematic design software, were 2mm pitch.
The IDC connector on the BBC Micro User Port is a 2.54 millimetre pitch.
The software I use automatically exports the part type over to the PCB design sheet.
I never even though to check that.
This added more cost and production time because I had to redesign the board and re-order.
Gutted !!!
But we did fix it. As can be seen on the next page.