Search found 604 matches

by myelin
Thu Apr 18, 2019 10:57 pm
Forum: for sale / freebies
Topic: Lots Of Duplicate Stuff On Everygamegoing
Replies: 5
Views: 146

Re: Lots Of Duplicate Stuff On Everygamegoing

Excellent :) When it came back from PayPal, I got an error about some PayPal process failing (sorry... didn't take a screenshot) but when I refreshed, the order showed up as paid and working fine, and I got a PayPal receipt. Glad it made it through to you!
by myelin
Thu Apr 18, 2019 9:31 pm
Forum: for sale / freebies
Topic: Lots Of Duplicate Stuff On Everygamegoing
Replies: 5
Views: 146

Re: Lots Of Duplicate Stuff On Everygamegoing

Very nice! I've placed an order for a bunch of my childhood favourites :)
by myelin
Tue Apr 16, 2019 5:48 am
Forum: hardware
Topic: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?
Replies: 95
Views: 3673

Re: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?

I haven’t posted in here for a bit... here’s a status update: - The Risc PC bootloader is working under emulation; I’m yet to test it on actual hardware. - The dual platform bootloader works great; one rom image for both Archimedes and RPC. - I’ve acquired an A310 and verified that the Arcflash hard...
by myelin
Mon Apr 15, 2019 3:26 am
Forum: hardware
Topic: A310 mono output works - no RGB
Replies: 10
Views: 237

Re: A310 mono output works - no RGB

I think I've figured it out for my case... I opened up the 9-pin RGB to SCART cable (advertised as an A3000 to SCART cable) and found that it was connected like this: - pin 20: CSYNC - pin 17: GND - pin 16: diode from pin 20 and capacitor to pin 17. - pin 15: R - pin 11: G - pin 7: B This is quite c...
by myelin
Sun Apr 14, 2019 2:46 am
Forum: hardware
Topic: A310 mono output works - no RGB
Replies: 10
Views: 237

Re: A310 mono output works - no RGB

Coincidentally I have this exact problem on an A310 I picked up off eBay a few weeks back. I believe I’ve eliminated the CMOS by running the Arcflash bootloader, which ignores the CMOS settings and just forces MODE 15 in a way that works fine on my A3000. I don’t have a monitor that’ll sync to what’...
by myelin
Tue Apr 09, 2019 8:25 pm
Forum: acorn atom and system
Topic: Atom 2k18 ?
Replies: 202
Views: 6111

Re: Atom 2k18 ?

What's the purpose of the split in the ground plane? (I assume purple = In2.Cu / bottom inner layer.)
by myelin
Tue Apr 09, 2019 1:41 pm
Forum: acorn atom and system
Topic: Atom 2k18 ?
Replies: 202
Views: 6111

Re: Atom 2k18 ?

Something I overlooked on my first 4 layer board: you want the ground plane to be the inner layer adjacent to your highest speed signals. So if your fast signals are on the top layer, put ground on the top inner layer and power on the bottom inner layer. If they’re on the bottom layer, make the bott...
by myelin
Sat Apr 06, 2019 10:56 pm
Forum: hardware
Topic: IDE->SD/CF Adapters (What works and what doesnt)
Replies: 23
Views: 1272

Re: IDE->SD/CF Adapters (What works and what doesnt)

Another success(-ish) report: I have my StrongARM Risc PC 600 booting with RISC OS 4.02 and a 16GB ADFS::4 drive made from the following: - A Monoprice Ultra IDE(40-pin) to Compact Flash Adapter (which is just a rebranded Syba one). I accidentally bought the kind with an IDE female plug rather than ...
by myelin
Sun Mar 31, 2019 10:58 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 300
Views: 20118

Re: Proposed: "The Ultimate Electron Upgrade"

I feel like Intel is particularly bad at this with the Max 10 documentation... I can’t find anything in their docs that explains that the 10M08SC only has one PLL, for example. No idea if that’s a “compact” or a “single supply” thing.
by myelin
Sun Mar 31, 2019 6:15 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 300
Views: 20118

Re: Proposed: "The Ultimate Electron Upgrade"

Update: I got it to build in Quartus with the correct chip as the target, using a combination of the DE1 project files and the Duo ULA VHDL. The only snag is that this chip only has one PLL, and it doesn’t support initialized memory. This means the 33.33 MHz clock will actually be more like 33.1 MHz...
by myelin
Fri Mar 29, 2019 6:44 pm
Forum: general
Topic: Today I received.....
Replies: 5108
Views: 375659

Re: Today I received.....

Some breakout boards for 44-pin XC9500XL CPLDs that I designed a while back... I have a ton of XC9536XL chips floating around, and figured these might come in handy to prototype stuff with.
0B8D8325-993C-4377-83C7-4C868C67DCA5.jpeg
by myelin
Wed Mar 27, 2019 6:40 am
Forum: hardware
Topic: Blitz - Originally known, by the designer, as "Arcin32" - The 32Bit IDE Interface
Replies: 34
Views: 1044

Re: Blitz - Originally known, by the designer, as "Arcin32" - The 32Bit IDE Interface

daveejhitchins wrote:
Tue Mar 26, 2019 7:17 pm
Building two prototypes at the moment - it's really difficult to do anything anymore - with all finger, arms, legs and toes crossed :lol:

If it all works then there'll be a loud noise on the Forum - if it doesn't work there'll be an equally loud silence :shock:
Exciting! Fingers crossed :)
by myelin
Tue Mar 26, 2019 1:24 am
Forum: hardware
Topic: all you van tell about a5000
Replies: 8
Views: 381

Re: all you van tell about a5000

Here's the text of the TRM, which is missing from Chris's Acorns: http://pi-star.co.uk/riscos/A5000TRM.pdf IC61 (next to the CPU) divides the 50MHz signal from X6 down to 25MHz for the CPU. PHI2 (12MHz bus clock) is generated by the MEMC1A. X2 generates the 36MHz clock input to the MEMC1A, which it ...
by myelin
Mon Mar 25, 2019 1:58 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 300
Views: 20118

Re: Proposed: "The Ultimate Electron Upgrade"

Update: BGA FPGA fanout more or less done. Pics and files available here as usual.

The next step will be to figure out the FPGA pinout, and fire up Quartus Prime to verify that I have all the pins correct.
by myelin
Sat Mar 23, 2019 3:09 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 677
Views: 29470

Re: RGB to HDMI using a Pi Zero and a small CPLD

Not really relevant to the case where you’re just making one board, but if you’re doing more than one (or it’s a board with a ton of pins, or any BGA or QFN parts) using a stencil and a hot plate for soldering is much much easier than doing it by hand, and far less failure prone — you’ll always get ...
by myelin
Fri Mar 22, 2019 5:33 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 300
Views: 20118

Re: Proposed: "The Ultimate Electron Upgrade"

Not sure about colliding with master ram board as tbh wasnt it said this would need mrb removed and normal 6502 or whatever put back in... Especially true if new ula is effectively gonna do similar adding faster memory. That's true! I'm going to try to make everything fit in the "safe" space identi...
by myelin
Fri Mar 22, 2019 1:49 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 300
Views: 20118

Re: Proposed: "The Ultimate Electron Upgrade"

Perfect, thanks Dave! Is the orientation correct in the first picture -- the board extends about 4cm towards the back of the machine and only 1cm to the left of the ULA? That makes more sense -- I think Dave has it rotated 90 degrees clockwise in his "big mess of wires" pics, which would have it pro...
by myelin
Thu Mar 21, 2019 6:49 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 300
Views: 20118

Re: Proposed: "The Ultimate Electron Upgrade"

Hoglet - do you have any diagrams showing which signals come out where on Dave's breakout board? Possibly; I'll need to dig back through my notebooks. I'll have a look over the weekend. Do remind me if I forget. You should be able to work it out by checking which pins are connected to ground. Thank...
by myelin
Thu Mar 21, 2019 5:34 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 300
Views: 20118

Re: Proposed: "The Ultimate Electron Upgrade"

Actually... one more question. The KiCad Package_LCC:PLCC-68_THT-Socket package has pin 1 in the middle of the top row of pins, whereas the Electron motherboard has a '1' marked near the top of the left hand side of the ULA footprint. Where is pin 1 really? Hoglet - do you have any diagrams showing ...
by myelin
Wed Mar 20, 2019 7:57 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 300
Views: 20118

Re: Proposed: "The Ultimate Electron Upgrade"

Glad your feeling a bit more normal :wink: Thanks! Time to start wiring it up... only 109 IOs to worry about :P Hardware on standby . . . :mrgreen: :) Forgot one thing -- a micro USB socket! Thanks to the TinyFPGA project, there's now an open source bootloader that handles all the USB interfacing w...
by myelin
Wed Mar 20, 2019 12:12 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 300
Views: 20118

Re: Proposed: "The Ultimate Electron Upgrade"

I can see again! So very nice to be able to once again read text on my phone and (with magnification) work with fine pitch QFP chips :) I think all my design questions here are now answered. The final one was what to do with the CAS OUT line, but I realized that because we're in an FPGA with a high ...
by myelin
Tue Mar 19, 2019 5:15 pm
Forum: software
Topic: Detecting Risc PC vs earlier machines in assembly code
Replies: 12
Views: 518

Re: Detecting Risc PC vs earlier machines in assembly code

So this all worked splendidly. I now have a build of my bootloader which fits in 384kB, and consists of: - first 336kB: cut-down RISC OS IOMD32 build with just kernel, HAL, and some IO modules - next 8 bytes: pointers to RPC and Arc versions of the bootloader - Arc (MEMC) bootloader - RPC (IOMD) boo...
by myelin
Tue Mar 19, 2019 1:06 am
Forum: hardware
Topic: Should i get an A3000 or a RISCPC ?
Replies: 36
Views: 973

Re: Should i get an A3000 or a RISCPC ?

soviet wrote:
Tue Mar 19, 2019 12:08 am
But ended up winning an auction in uk for a a3000 4 megs ram that have the battery redone having pictures from the inside and is tested and seem to be en very good condition including mouse for a great price 160 GBP :D
Congratulations! Sounds like a nice machine :)
by myelin
Mon Mar 18, 2019 10:04 pm
Forum: hardware
Topic: PCF8583 breakout board
Replies: 7
Views: 442

Re: PCF8583 breakout board

For anyone interested here, I've designed a small PCB which includes the PCF8583 (through hole version), crystal, and supporting components . It has two diodes, so you can wire in an off-board battery -- assuming that you'll have a pair of AA batteries mounted somewhere far away from the sensitive s...
by myelin
Mon Mar 18, 2019 9:29 pm
Forum: hardware
Topic: A5000 woes
Replies: 26
Views: 1595

Re: A5000 woes

One thing to remember, with flux . . . it needs 'activating'! - I find, with stubborn joints: apply the flux and heat, allowing it do its job. Then apply soldering iron. This also helps to reduce thermal shock to the part being worked on. I didn't know that! So I should apply flux, heat it a bit wi...
by myelin
Mon Mar 18, 2019 8:07 pm
Forum: hardware
Topic: A5000 woes
Replies: 26
Views: 1595

Re: A5000 woes

Lots and lots of flux and a hot air reflow gun should do a good job. Hot air reflow gun ordered! In the meantime I've tried reflowing with a soldering iron and flux pen; no luck bringing any of the connections back to life, although it bubbled nicely and I did see a small solder ball forming on my ...
by myelin
Mon Mar 18, 2019 7:47 pm
Forum: general
Topic: Today I received.....
Replies: 5108
Views: 375659

Re: Today I received.....

Some breakout boards for 6-pin and 9-pin mini DIN sockets, so I can use a pre-made mini DIN cable to connect a SmallyMouse2 to my A3000 rather than having to wire it up myself, and so I can hook up an Archimedes keyboard.
2019-03-18 12.43.51.jpg
by myelin
Mon Mar 18, 2019 6:20 am
Forum: hardware
Topic: Another A5000
Replies: 15
Views: 338

Re: Another A5000

Oh dear. That A5000 doesn’t look much better than the one I’m trying to repair right now. If it boots to the supervisor you’re doing better than I am, though — mine needs some soldering and perhaps replacement wiring to get working again. Good luck! (But also... if vinegar washing your motherboard a...
by myelin
Sun Mar 17, 2019 1:14 am
Forum: hardware
Topic: A5000 woes
Replies: 26
Views: 1595

Re: A5000 woes

Looks like I may have overdone the vinegar washes... here’s the “before” photo: 8C176905-5C59-43DB-A044-5A61902E8B20.jpeg And after: E65E1AC7-185A-4C0A-A3A6-97A805BCD52E.jpeg Managed to get rid of quite a bit of verdigris, at least. Looks like quite a few address lines are disconnected, although the...
by myelin
Thu Mar 14, 2019 5:32 pm
Forum: hardware
Topic: Should i get an A3000 or a RISCPC ?
Replies: 36
Views: 973

Re: Should i get an A3000 or a RISCPC ?

They are all "untested" no pictures of the insides, and i have seen pictures and videos about the internal battery that seem to completely destroy the boards. Yeah, that's pretty much the state of things for any of the machines with soldered batteries (A3000, A4000, A5000, RPC). You have two unappe...