Search found 249 matches

by myelin
Sat Jan 13, 2018 7:06 pm
Forum: hardware
Topic: Simple Electron flash cartridge with 39SF010 + 74HCT00
Replies: 59
Views: 3129

Re: Simple Electron flash cartridge with 39SF010 + 74HCT00

Excellent! Sorry about the as65/beebasm mixup; this was my first Electron hardware project and I really was just learning the ropes at that point. I think tester.asm was the first 6502 assembly I’d written in 20+ years! When I get some time to verify everything I’ll go remove tester.asm and move the...
by myelin
Fri Jan 12, 2018 11:06 pm
Forum: hardware
Topic: Myelin's Electron PiTubeDirect Interface - Support thread
Replies: 0
Views: 73

Myelin's Electron PiTubeDirect Interface - Support thread

Now that some others are assembling this board, I'm starting a support thread for it. https://github.com/google/myelin-acorn-electron-hardware/tree/master/elk_pi_tube_direct This is an Electron cartridge that takes an XC9536XL or XC9572XL chip and provides level shifting and addressing so you can co...
by myelin
Fri Jan 12, 2018 11:00 pm
Forum: hardware
Topic: Simple Electron flash cartridge with 39SF010 + 74HCT00
Replies: 59
Views: 3129

Re: Simple Electron flash cartridge with 39SF010 + 74HCT00

I have one of these boards available. If you'd like it, please pm me with your details (if I haven't already got them) Postage costs only, first class large letter. Sorry - This has now gone! I believe I have a few more of these in stock, so if anyone would like me to post them one, PM me with your...
by myelin
Fri Jan 12, 2018 9:09 pm
Forum: off-topic
Topic: Decoupling capacitor for ic
Replies: 9
Views: 229

Re: Decoupling capacitor for ic

At 2MHz you don't have to be super precise with your capacitors. You may even find that your hardware works fine without them... I've seen microcontrollers running off battery power with no decoupling. There's a tiny amount of capacitance on the chip itself, plus you get some for free from the trace...
by myelin
Wed Jan 10, 2018 9:50 pm
Forum: hardware
Topic: Plus1 Cart slot enables?
Replies: 4
Views: 161

Re: Plus1 Cart slot enables?

More background... Acornsoft cartridges from the 80s have room for two ROMs on board; presumably one of them has an active-high CS and the other has an active-low /CS, with both wired to the ROMQA line. Modern cartridges usually just use one chip. My 32kB flash cartridge uses a 128kB flash chip and ...
by myelin
Wed Jan 10, 2018 9:41 pm
Forum: hardware
Topic: Plus1 Cart slot enables?
Replies: 4
Views: 161

Re: Plus1 Cart slot enables?

hicks wrote:I get the feeling I'm missing something here and will rapidly go #-o with the first reply to this post but here goes...

The answer here is the ROMQA line, which passes the LSB of the bank select value to the cartridge :)
by myelin
Tue Jan 09, 2018 11:06 pm
Forum: hardware
Topic: Fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 938

Re: Fast serial port/SD card adapter for the 1MHz Bus

TBH I think the best way to implement really fast serial would be to connect the Pro Micro directly to your FPGA, or to use a spare CPLD pin from the serial board as a "byte available" flag (or two pins for "received byte available" and "transmit buffer is empty"). I ca...
by myelin
Tue Jan 09, 2018 1:27 am
Forum: hardware
Topic: Fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 938

Re: Fast serial port/SD card adapter for the 1MHz Bus

I see what you're getting at with the main transfer loop, I wasn't sure whether one had to check for esc/0 during transfers? I was hoping that this might be a candidate for some DMA acceleration but as its a byte based protocol I suspect not without a lot of changes to the protocol... Changing it t...
by myelin
Tue Jan 09, 2018 12:25 am
Forum: hardware
Topic: Fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 938

Re: Fast serial port/SD card adapter for the 1MHz Bus

It's still (only) about as fast as MMFS, I reckon with a bit of tickling it might be possible to get it going a little faster. I'm not sure where the bottle neck is though, the client or the perl server? Mostly in the client, as far as I can tell. HostFS was written for a 19.2kb/s serial port rathe...
by myelin
Mon Jan 08, 2018 8:38 pm
Forum: hardware
Topic: Fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 938

Re: Fast serial port/SD card adapter for the 1MHz Bus

Aha. I'll try TAB later. No the serial port has been pretty straightforward. Thus is running the perl server under Cygwin. Do you know is there any way of getting two usb com ports on those uControllers? Having hostfs and noIce at the same time would be immense! That's a really good idea! I hadn't ...
by myelin
Mon Jan 08, 2018 7:27 pm
Forum: hardware
Topic: Fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 938

Re: Fast serial port/SD card adapter for the 1MHz Bus

Woo hoo! PS: How do I select on break? U,H don't seem to work Awesome! Did you run into any issues getting TubeHost to recognize the serial port? I had to mess around with it quite a bit on my Mac, although I was also trying to debug my UPURS adapter at the same time, which probably made it a lot h...
by myelin
Mon Jan 08, 2018 6:40 pm
Forum: hardware
Topic: Fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 938

Re: Fast serial port/SD card adapter for the 1MHz Bus

I just gave it a quick shot. I recompiled UPURSFS with the new locations but I just get "UPURSFS no selected; no RTS" is there other stuff I need to disable/enable? The trick is that you actually want to compile *HOSTFS*, not *UPURSFS*, because my board just looks like the Beeb's serial p...
by myelin
Mon Jan 08, 2018 2:20 am
Forum: hardware
Topic: Fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 938

Re: Fast serial port/SD card adapter for the 1MHz Bus

I've still not tried the SD adaptor yet but the serial port is brilliant! I got half an hour earlier and hacked together a driver for the very useful NoIce debugger . At 19,200 this was usable but a bit hesitant when single-stepping with a lot of watches set up, now even when its fetching a load of...
by myelin
Sat Jan 06, 2018 9:11 pm
Forum: hardware
Topic: What's the worst that could happen?
Replies: 16
Views: 514

Re: What's the worst that could happen?

crj wrote:Lost that one too. Bidding on another.

I'm now up to twice what I originally intended to pay. Grr!

What’s your budget? I’m sure someone on here might be able to help. I feel like random Beebs usually sell on eBay for £65-80, with Retroclinic-refurbished ones about double that.
by myelin
Sat Jan 06, 2018 7:19 pm
Forum: hardware
Topic: A3020 Restoration
Replies: 14
Views: 301

Re: A3020 Restoration

If it’s an IDE hard drive, attaching it to a Linux box and imaging it with ddrescue will give you a nice image of it, in case anything goes wrong on the host A3020.
by myelin
Sat Jan 06, 2018 8:16 am
Forum: hardware
Topic: Myelin's FX2 Tube/Cartridge Adapter - Development and Support
Replies: 12
Views: 337

Re: Myelin's FX2 Tube/Cartridge Adapter - Development and Support

Perfect — I’ll post a few to you next week, Dave, and maybe you can get Marcus sorted out too. Hehe... looking forward to seeing what you make of all the boards in that aforementioned stash. I believe the one that attracted the most interest was the USB cartridge programmer, but there’s also some El...
by myelin
Fri Jan 05, 2018 10:28 pm
Forum: hardware
Topic: What's the worst that could happen?
Replies: 16
Views: 514

Re: What's the worst that could happen?

Definitely avoid doing initial testing of any hardware on a machine you *really* care about :) Maybe drop Mark at Retroclinic a line and ask if he has any beat up Model B machines or motherboards to sell. For your particular application you would probably be quite happy with one with a lot of damage...
by myelin
Fri Jan 05, 2018 6:19 pm
Forum: hardware
Topic: Myelin's FX2 Tube/Cartridge Adapter - Development and Support
Replies: 12
Views: 337

Re: Myelin's FX2 Tube/Cartridge Adapter - Development and Support

By the way, what was the rationale for not powering the Pi from the adapter board? I assumed it wouldn't work after reading this in App Note 14: "No more than 150mA should be drawn by a cartridge in a fully configured Master 128 computer, ie with internal co-processor fitted. No more than 50mA...
by myelin
Fri Jan 05, 2018 6:03 pm
Forum: hardware
Topic: Myelin's FX2 Tube/Cartridge Adapter - Development and Support
Replies: 12
Views: 337

Re: Myelin's FX2 Tube/Cartridge Adapter - Development and Support

Excellent! I think this means that now, between the two of us, we've seen it working on Elk (with my CPLD-based cartridge expansion, and with your Plus 1 and various original expansions), Beeb, and Master 128. I'll update the docs accordingly. I had missed the "-c" argument to decode6502; ...
by myelin
Fri Jan 05, 2018 8:25 am
Forum: hardware
Topic: Open source firmware for Gotek floppy emulator released
Replies: 56
Views: 3013

Re: Open source firmware for Gotek floppy emulator released

I finally got around to trying the Gotek + FlashFloppy on my Master 128 and it worked very nicely! I don't have any ADFS images to try with, but it worked well with single sided 80 track (200k) DFS disks. I used the command line 'hxcfe' tool, which autodetected the format once I padded the files out...
by myelin
Fri Jan 05, 2018 6:50 am
Forum: hardware
Topic: Myelin's FX2 Tube/Cartridge Adapter - Development and Support
Replies: 12
Views: 337

Re: Myelin's FX2 Tube/Cartridge Adapter - Development and Support

I've spent some time this evening trying this out on a Master 128, with some mixed results. The board works nicely as a PiTubeDirect adapter when connected to the Tube port. It requires different VHDL from the Electron version, because it needs to use the /TUBE signal from the Tube port rather than ...
by myelin
Thu Jan 04, 2018 10:47 pm
Forum: software & utilities for the pc, mac or unix
Topic: BBC micro style keycaps for modern keyboard
Replies: 26
Views: 628

Re: BBC micro style keycaps for modern keyboard

⋅ What are we actually going to have printed on the key caps? If we do an identical run of the key switches that exactly matches what was on the Beeb, then that would imply making some specialised Beeb keyboard - that in turn would mean spinning a PCB for the keyboard - easily do-able, bu...
by myelin
Thu Jan 04, 2018 7:58 pm
Forum: software & utilities for the pc, mac or unix
Topic: BBC micro style keycaps for modern keyboard
Replies: 26
Views: 628

Re: BBC micro style keycaps for modern keyboard

They still have the tooling to recreate the double shot (injection molding in two stages) BBC Micro key caps in the same typeface they have always used, called Gorton Modified. They are pricing it up now. I expect it will be expensive and probably only worth doing with a Kickstarter / group buy... ...
by myelin
Thu Jan 04, 2018 7:56 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 103
Views: 4418

Re: Open Source Logic Analyzer Experiments

FYI I've started a new thread for discussion of my adapter board: http://www.stardot.org.uk/forums/viewto ... =3&t=14319
by myelin
Thu Jan 04, 2018 7:55 pm
Forum: hardware
Topic: Myelin's FX2 Tube/Cartridge Adapter - Development and Support
Replies: 12
Views: 337

Re: Myelin's FX2 Tube/Cartridge Adapter - Development and Support

Nice work on the assembly! I just hand soldered everything for my board; the trick with the 0805 discretes is to put a blob of solder on one pad, then pick up the chip with tweezers, then hold the soldering iron on the pad with the blob of solder on it, push the chip into the molten blob, take the s...
by myelin
Thu Jan 04, 2018 5:57 pm
Forum: hardware
Topic: Myelin's FX2 Tube/Cartridge Adapter - Development and Support
Replies: 12
Views: 337

Myelin's FX2 Tube/Cartridge Adapter - Development and Support

Branching this off from Hoglet's Open Source Logic Analyzer thread ... This thread is for discussion of the FX2 Tube/Cartridge Adapter board I designed to make it easy to use Hoglet's work with the lcsoft fx2 mini, fx2pipe, and sigrok, to monitor the bus on your Electron, BBC, or Master. It also han...
by myelin
Wed Jan 03, 2018 2:02 am
Forum: hardware
Topic: Fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 938

Re: Fast serial port/SD card adapter for the 1MHz Bus

I got the solder station out this afternoon and put the thing together. So far I've only tried the serial port and it is working nicely! It is very fast, lovely to see a screenfull of Mode 0 popping up on the beeb in the flicker of an eye! Nice work! It's really exciting to see this up and running;...
by myelin
Tue Jan 02, 2018 9:30 pm
Forum: for sale / freebies
Topic: Floppy interface for Raspberry Pi
Replies: 12
Views: 641

Re: Floppy interface for Raspberry Pi

Jasper just posted me a board. I'll document the assembly process when it arrives. He says he's modified BeebEm to be able to take the 160MB raw (double sided 80 track DFS) disk image files, and it's working well. He also has some new code that hasn't made it up to GitHub yet.
by myelin
Tue Jan 02, 2018 8:40 pm
Forum: software & utilities for the pc, mac or unix
Topic: BBC micro style keycaps for modern keyboard
Replies: 26
Views: 628

Re: BBC micro style keycaps for modern keyboard

Myelin... once we have some nice SVGs, maybe we we could get a group order in, Setting up a single print run for keys is very expensive. With a few backers the price could come down considerably... I'm interested in this (as long as the keycaps are Cherry MX compatible). Looking at my notes from a ...
by myelin
Tue Jan 02, 2018 8:52 am
Forum: software & utilities for the pc, mac or unix
Topic: BBC micro style keycaps for modern keyboard
Replies: 26
Views: 628

Re: BBC micro style keycaps for modern keyboard

Excellent thanks Lazrus! Would you object to us sticking the SVG on GitHub (or similar) and working on smoothing out the wrinkles, creating a community keyset? If this can go up on GitHub under one of the standard open source licenses (Apache, GPL, MIT, BSD), that would be amazing -- my employer's ...

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