stardot.org.uk

1920x1080 here!

I'd be very interested in one (HAT + cable, shipped to San Francisco). Really glad to see this project reaching this stage Thanks Dave!

I'm probably going to be switching this between machines, and mounting it behind a monitor, so can I have a 100cm cable please?

Me too!

The only problem is the Y/PA/PB signals are relatively low voltage swing and tri-level (with some redundancy). Figure 10 in the 6847 data sheet best explains this. In the FPGA I use the differential LVDS I/O cells rather than external comparators. Each of PA and PB uses a pair of LDVS I/O cells, wh...

hoglet wrote: ↑

Sat Jul 07, 2018 1:13 pm

And lo and behold....
P1030968.JPG
(this was on an Issue 4 Elk)

Nice work! Looking forward to building up a few of these so I can have more than one machine with a display at once

8bitkick wrote: ↑

Sun Jul 08, 2018 4:34 am

Until you get your MMC this might be useful. I just saw your post which prompted me to get in online...

Thank you! Yes, that'll be super useful! Are you bringing your Atom to VCF? There's a slight chance that mine might arrive in time...

What's you plan in terms of extensions? Not sure yet! AtoMMC2 seems like an excellent start. I like the look of your scan converter. Also, do you think your RGBtoHDMI hardware could be adapted to work here? I guess you would need comparators on the inputs...? I'm still figuring out how the whole Y/...

After staring at it on eBay for a couple of weeks, I finally cracked and bought the 200 euro Atom from backtoyourpast (pricey, but out of the Atoms I've seen whose owners will ship to the USA, it seemed bearable). So... I expect to be an Atom owner once it arrives in San Francisco

A couple of things got me thinking on various threads about what is not about for the Electron, a dredge of previous threads really. - With Daniel's freewifi for the serial port ... nowhere to plug it in on Electron ... and no serial port remakes - With Beebmasters Eco hubs .... dont think there wa...

This does sound interesting, would be fun to connect a virtual arc to a virtual beeb over a virtual network :) Indeed! Hoping to do exactly that, and maybe have it use an USB Econet adapter (either my half-finished one, or flynnjs's one) as a bridge onto a real Econet. Not sure if that would play w...

It looks like Circle (bare-metal Pi programming environment) has network, USB, and SD card drivers, plus some other possibly useful bits and pieces, so the approach of using the CPLD as a level shifter and doing everything in the Pi may actually work, as long as the drivers for current podules use s...

meylin's idea is for all the communication between the host & Pi to be via the podule interface, similar to Pi-based coprocessors on the beeb. This will result in much tighter integration with the host, including the potential for it to be used to emulate existing IDE/network/etc. podules. But I'm ...

An idea I've been batting around for a while, after acquiring an A3000 and reading all the threads about IDE and networking podules, is to make a simple podule (well, mini-podule) that contains a flash chip, a CPLD, and a header for a Raspberry Pi. The mini-podule interface has 35 pins, and we want ...

Welcome! And that is a *very* clean looking Beeb! The motherboard and keyboard look brand new...

Would you be open to uploading the .sch files (pictured in the PDFs), and possibly your kicad_pcb file with everything except the connectors and board layout deleted, for interested folks to use as a starting point? (That way we can build on a verified base.) Here are my KiCad projects, I encourage...

Based on? You have to read the datasheet to see which IO are FT as some are but not others. The F103 has a dozen or so FT GPIO in the QFP on the cheap boards. Huh... and you're right. I just rechecked the STM32F103x8/xB datasheet, and it says that almost all the GPIO pins are 5V tolerant. I wonder ...

Gave up and just started snipping pins... finally found that IC6 was the culprit. Snipping its pin 1 made the machine boot again, although the Plus 1 ROM and MGC were invisible. Scoping IC6 pin 1 showed that it was sitting around 0.1V, which would have kept the bank select register cleared. Tying it...

Usually with this sort of issue, there is a low resistance path to ground inside the failed chip. Start by measuring the resistance with the Plus one disconnected. It's probably a few hundred ohms. (Try the meter lead both ways around). Good thinking! My meter measured a total open circuit in one d...

Note that the STM32F103 (Cortex-M3) chips used in the cheap boards from China are not 5V tolerant. I believe the STM32F407 (Cortex-M4) chip used in the STM32 F4 DISCOVERY board has a lot of GPIOs that are 5V tolerant and use TTL signalling levels, so they can be connected directly to 80s/90s hardwa...

If you haven't found the Plus 1 schematic, it's attached. The reset line goes to 4 x ICs! Could be a short or a faulty IC i.e. one of the input's doing the pulling-down . . . Yep... one for the bank select latch, and three for the parallel port (main buffer, status input, and strobe output). I'm gu...

Figured out part of what's going on... scoping up the reset pin, it's glitching low in sync with the rising edge of PHI0: Screenshot 2018-06-10 22.59.01 reset glitches.png I realized that I can get the same red/yellow pattern on screen by holding down BREAK on startup, so this confirms that the prob...

Going through a lot of my old hardware right now to get it ready for exhibition at VCF West with 8bitkick and Lion , and the key thing to get going is my Plus 1... time to take another look at it :) I tried the fibre pencil approach when Dave suggested it (over a year ago now!) but it's still flaky:...

GitHub would be great. I'm starting to understand Mercurial and Bitbucket a bit better after submitting a few changes to Arculator, but I'm still much more familiar with Git

I'm doing some work with Elkulator (getting it to replay bus cycles recorded from a real machine) and there seem to be several repositories around, none of which claims to be the canonical one. I'm guessing David Boddie's Bitbucket repo is the one to go with... is that right?

As some of you may have noticed, with the help of John Kortink I've made and sold a few IDE interfaces. The building and posting of PCB's is not something I want to do long-term, so I'm making the designs available, so anyone can make IDE interfaces. This is awesome! Thank you Ian! I'm not currentl...

You should have a cream-coloured self adhesive label, which must be fixed to the Electron before attaching the Plus 3. This label is made from a metallic substance, and its purpose is to provide an electromagnetic field between the Electron and the Plus 3. This will improve the performance of your ...

A project suggestion for anyone looking for one: embed 6502Decoder into b-em so you can capture machine state from a real machine and resume in the emulator (or use an attached machine as a monitor). Update: I've started on this, except with Elkulator, because I'm hoping to show off my heavily modif...

It shouldn’t be hard to adapt this code to run directly on a Pi, using its GPIO pins for the JTAG connection. Will have to look into that when I’m back :) It’s also possible that openocd already supports this Pi GPIO method (see: https://electronics.stackexchange.com/a/101482 ), in which case you ca...

I checked in my cpld programming notes: https://github.com/google/myelin-acorn-electron-hardware/blob/master/notes/pld_programming_and_jtag.md Also started on a simple cpld programmer Arduino sketch, which should make it possible to program the cplds on my boards with just an Arduino Leonardo or Pro...

That’s right... I’ve started committing .bit and .svf files into git, so people can do that, but have been fairly haphazard about it so far. Need to do a proper sweep through all the projects and bring them all up to date!