Myelin's USB Electron Cartridge Interface
Myelin's USB Electron Cartridge Interface
PROJECT STATUS: built and tested, and it works fine! I don't have any built up ones for sale, but will post you a circuit board for free if you can acquire the components and solder it yourself. (Updated May 22, 2019 -- I have three boards available.)
PCBs arrived in the mail today, and I just soldered up the first board!
CPLD + AVR + cartridge socket, so I can talk to Electron cartridges from my Mac.
PCB and untested VHDL: https://github.com/google/myelin-acorn- ... programmer
PCBs arrived in the mail today, and I just soldered up the first board!
CPLD + AVR + cartridge socket, so I can talk to Electron cartridges from my Mac.
PCB and untested VHDL: https://github.com/google/myelin-acorn- ... programmer
Last edited by myelin on Wed May 22, 2019 6:47 pm, edited 2 times in total.
SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Re: USB Electron Cartridge Interface
Success! Just got it to read out a Countdown to Doom cartridge 

SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Re: USB Electron Cartridge Interface
Well done!
This looks like it could be very useful for programming EEPROM/Flash cartridges - would it work for that purpose?

Re: USB Electron Cartridge Interface
Yep! That's the next thing I'm going to work on; right now it reads just fine but I haven't implemented writes (RnW is always high right now) or access to &FCxx/&FDxx. I made this mostly for debugging, but also so I can program flash cartridges outside the Electron. I haven't been able to find a way to tell the Electron to ignore cartridges on boot, which means that a cartridge containing code that causes a crash on startup is effectively bricked unless you have an external programmer like this.davidb wrote:Well done!This looks like it could be very useful for programming EEPROM/Flash cartridges - would it work for that purpose
I've just soldered up the one board, but I have a stack of 9 more PCBs if anyone is interested in one, and I'm happy to part with a few of them at cost for folks I know will make good use of them

SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Re: USB Electron Cartridge Interface

- 1024MAK
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Re: USB Electron Cartridge Interface
Yepsirmorris wrote:nice board!


Mark
For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
BeebWiki - for answers to many questions...
Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems
BeebWiki - for answers to many questions...
Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems
- 1024MAK
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Re: USB Electron Cartridge Interface
The normal way of doing this in hardware, is to have a two pin header / link / jumper shunt in series with the EEPROM or EPROM /CS (/CE) control line pin, with a 10k pull up resistor on the EEPROM or EPROM side. A production PCB can have the two link pads joined via a thin track. While on a development PCB, you cut the track, then either use a jumper shunt, or wire the pin header to a SPST switchmyelin wrote:I haven't been able to find a way to tell the Electron to ignore cartridges on boot, which means that a cartridge containing code that causes a crash on startup is effectively bricked unless you have an external programmer like this.

I'm interestedmyelin wrote:I've just soldered up the one board, but I have a stack of 9 more PCBs if anyone is interested in one, and I'm happy to part with a few of them at cost for folks I know will make good use of themThere's about US$11 of parts on there, and it looks like shipping to the UK would be about US$14, so we're talking about US$25 or £20 (although I could possibly ship a few to one person and have them distribute them).

Whereabouts in the world are you? As you are using US$, are you in the USA? One consideration we folk in Europe have for items sent from outside the EU, is import tax. For the UK, anything costing £15 of more, including the cost of postage will be charged VAT plus an handling fee of £8. VAT is currently 20%.
So at the current exchange rates, anything approaching US$19 gets us near the threshold

If you can let me know the size of the PCB, I can work out the cost of postage within the UK. And if required, the cost to other EU countries.
I'm happy to forward the PCBs to other Stardot members if you would like me to.
Mark
For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
BeebWiki - for answers to many questions...
Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems
BeebWiki - for answers to many questions...
Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems
Re: USB Electron Cartridge Interface
Or just lie on the customs form. Just saying. Don't judge me.
- 1024MAK
- Posts: 10475
- Joined: Mon Apr 18, 2011 5:46 pm
- Location: Looking forward to summer in Somerset, UK...
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Re: USB Electron Cartridge Interface
"You might very well think that; I couldn't possibly comment..."sirmorris wrote:Or just lie on the customs form.

Mark
For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
BeebWiki - for answers to many questions...
Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems
BeebWiki - for answers to many questions...
Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems
Re: USB Electron Cartridge Interface
And so the house of (expansion) cards falls.. 

Re: USB Electron Cartridge Interface
I'm in San Francisco, so it sounds like the tax thing is going to be pretty unavoidable, unless someone over there wants to acquire components and do the assembly, in which case I'd be happy to post over a few PCBs. The £8 handling fee and the postage means that sending them in bulk and having you forward them out is almost certainly the best plan.1024MAK wrote:I'm interested![]()
Whereabouts in the world are you? As you are using US$, are you in the USA? One consideration we folk in Europe have for items sent from outside the EU, is import tax. For the UK, anything costing £15 of more, including the cost of postage will be charged VAT plus an handling fee of £8. VAT is currently 20%.
So at the current exchange rates, anything approaching US$19 gets us near the threshold. Now, it may actually work out cheaper to take the tax hit in one go and ship everyone’s boards in a single package from you rather than sending individual packets to individuals. Hence me giving you the details.
If you can let me know the size of the PCB, I can work out the cost of postage within the UK. And if required, the cost to other EU countries.
I'm happy to forward the PCBs to other Stardot members if you would like me to.
FYI I'm working on a few other things that folks may be interested in... a simple expansion ("Minus One") that gives three cartridge slots (but none of the other features of the Plus One), and also a 32k dual ported SRAM cartridge that you can read/write over USB as well as from the Electron. And some more flash cartridge designs (one that's super short, so it barely pokes out the top of the Plus One, and one that is exactly the same form factor as the PCBs in the Acornsoft cartridges). So you may or may not want to wait until I have more designs to send over as well

SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
- daveejhitchins
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Re: USB Electron Cartridge Interface
Just a thought . . .
Could we get the boards made from this end? That's if you're willing to share the board Data?
Dave H
Could we get the boards made from this end? That's if you're willing to share the board Data?
Dave H

Re: USB Electron Cartridge Interface
See the link in the first message, Dave. 

Re: USB Electron Cartridge Interface
Yup, that's absolutely fine! Double check with me before ordering anything so I can make sure the latest gerbers etc are up on github, but this is all open source and I'd love it if you or anyone else here would like to make some 

SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Re: USB Electron Cartridge Interface
Interesting... Although I have a BBC Master.
btw, is there an Acorn fan/user group in the San Francisco bay area? I'm in the south bay area.
btw, is there an Acorn fan/user group in the San Francisco bay area? I'm in the south bay area.
- daveejhitchins
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Re: USB Electron Cartridge Interface
I probably read that, but it was earlier than yesterday . . . You can't ask me to remember everythingdavidb wrote:See the link in the first message, Dave.

If anyone is interested I'll be willing to host the purchase and distribution?
Dave H

Re: USB Electron Cartridge Interface
Oh good, someone else in this part of the world! I grew up in New Zealand, where Acorn machines were pretty dominant for a while, and wasn't sure if anyone else in the Bay Area knew about thematcurtis wrote:Interesting... Although I have a BBC Master.
btw, is there an Acorn fan/user group in the San Francisco bay area? I'm in the south bay area.

SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Re: USB Electron Cartridge Interface
myelin, atcurtis - you guys have seen the google maps thread, haven't you?
http://www.stardot.org.uk/forums/viewto ... =41&t=8933
http://www.stardot.org.uk/forums/viewto ... =41&t=8933
Re: USB Electron Cartridge Interface
Excellentdaveejhitchins wrote:If anyone is interested I'll be willing to host the purchase and distribution?

SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Re: USB Electron Cartridge Interface
Now I have.sydney wrote:myelin, atcurtis - you guys have seen the google maps thread, haven't you?
http://www.stardot.org.uk/forums/viewto ... =41&t=8933
Re: USB Electron Cartridge Interface
I am British and I grew up in England. I just live/work in the SF bay area these days. I wasted a lot of time playing Elite in my youthmyelin wrote:Oh good, someone else in this part of the world! I grew up in New Zealand, where Acorn machines were pretty dominant for a while, and wasn't sure if anyone else in the Bay Area knew about thematcurtis wrote:Interesting... Although I have a BBC Master.
btw, is there an Acorn fan/user group in the San Francisco bay area? I'm in the south bay area.There's a guy here at the SF Google office who nearly worked for Tynesoft (they went out of business before his internship started). No idea if there's an official group, although I imagine if we keep mentioning SF on Stardot, more of us Bay Area folks will come out of the woodwork!

Re: USB Electron Cartridge Interface
FYI I've verified that writing to cartridges (everything that uses nOE or nINFC, at least) works over the USB interface. I could read out all 256 ROM images from my MGC (by writing 0 to &FC08 and then cycling through setting &FC00=0 to 127 and reading banks 0 and 1).daveejhitchins wrote:If anyone is interested I'll be willing to host the purchase and distribution?
How about I post you a few PCBs and you can decide what to do with them? No cost; I don't need all of mine so you can have as many as I can convince USPS to post over without charging me a fortune

SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
- daveejhitchins
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Re: USB Electron Cartridge Interface
Yes please
I'll ensure that people who will actually make good use of these will have one.
Many thanks - Dave H
If anyone would like a board, please pm me.


Many thanks - Dave H

If anyone would like a board, please pm me.
Re: USB Electron Cartridge Interface
It took me four and a half months to get around to it, but I finally posted some of the boards off to Dave
Totally unassembled, so there'll be a bit of pottering around to get them working, but folks in the UK might finally get to play with these in a little bit!

SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.
- daveejhitchins
- Posts: 6081
- Joined: Wed Jun 13, 2012 6:23 pm
- Location: Newton Aycliffe, County Durham
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Re: USB Electron Cartridge Interface
^^^ Just a reminder.daveejhitchins wrote:If anyone would like a board, please pm me.
Thanks Phil . . .
Dave H

Re: USB Electron Cartridge Interface
San Jose here! Relocated Brit. Acorn Atom, BBC, Electron and A3000 seemed to follow me here...myelin wrote:Oh good, someone else in this part of the world! I grew up in New Zealand, where Acorn machines were pretty dominant for a while, and wasn't sure if anyone else in the Bay Area knew about thematcurtis wrote:Interesting... Although I have a BBC Master.
btw, is there an Acorn fan/user group in the San Francisco bay area? I'm in the south bay area.There's a guy here at the SF Google office who nearly worked for Tynesoft (they went out of business before his internship started). No idea if there's an official group, although I imagine if we keep mentioning SF on Stardot, more of us Bay Area folks will come out of the woodwork!
One idea crossed my mind - get down to Vintage Computer Festival West next year with Acorn machines and represent!
http://vcfed.org/wp/festivals/vintage-c ... ival-west/
- daveejhitchins
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- Joined: Wed Jun 13, 2012 6:23 pm
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Re: USB Electron Cartridge Interface
Oh yes . . . You've just got to go when they're saying this:8bitkick wrote:One idea crossed my mind - get down to Vintage Computer Festival West next year with Acorn machines and represent!
and check-out if they have the full Acorn kit!VCFW Says wrote:Don’t forget — CHM is the world’s best computer museum . . .

If you need anything (?) I'm sure we should be able to assist, somehow!
Dave H

Re: USB Electron Cartridge Interface
Thanks Dave! The CHM (where they host VCFW yearly) is excellent... I have a membershipdaveejhitchins wrote:Oh yes . . . You've just got to go when they're saying this:8bitkick wrote:One idea crossed my mind - get down to Vintage Computer Festival West next year with Acorn machines and represent!and check-out if they have the full Acorn kit!VCFW Says wrote:Don’t forget — CHM is the world’s best computer museum . . .![]()
If you need anything (?) I'm sure we should be able to assist, somehow!
Dave H

Along with an Apple I signed by Woz and the original Apollo Guidance Computer that is

VCFW happens yearly and enthusiasts come along to demo their working machines. Would love to join some stardot friends there and represent acorn machines
I will start a seperate thread to see if/how we can get a California ABUG going

- daveejhitchins
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Re: USB Electron Cartridge Interface
I have four three of these boards available. If you'd like one, please pm me with your details (if I haven't already got them) Postage costs only, first class large letter.
One board per person, first come etc.
If you'd like me to fit the SMD parts just send them along.
Dave H
Other boards from myelin:
Flash Cartridge
******************************************************
Acorn Electron PitubeDirect Interface
I have four three two of these boards available - same rules as above. ******************************************************
One board per person, first come etc.
If you'd like me to fit the SMD parts just send them along.
Dave H

Other boards from myelin:
Flash Cartridge
******************************************************
Acorn Electron PitubeDirect Interface
I have four three two of these boards available - same rules as above. ******************************************************