Search found 512 matches

by dominicbeesley
Fri Feb 16, 2018 3:26 pm
Forum: hardware
Topic: 65c02 VHDL/Verilog core
Replies: 2
Views: 158

Re: 65c02 VHDL/Verilog core

Thanks Dave, these both look the part! I'll have a play and report back if I ever get time to finish this board!

D
by dominicbeesley
Fri Feb 16, 2018 11:49 am
Forum: hardware
Topic: 65c02 VHDL/Verilog core
Replies: 2
Views: 158

65c02 VHDL/Verilog core

Hello, I'm about to send off my latest (blit/dma/cpu/sound) board for fabrication and was wondering how to test this in a master. In the beeb I've tended to first bring these up using a VHDL core (T65) which works well and I'm familiar with. However, I know that the T65 core is incomplete and doesn'...
by dominicbeesley
Tue Feb 13, 2018 12:56 am
Forum: hardware
Topic: bbc master RDY
Replies: 3
Views: 232

Re: bbc master RDY

Thanks for that Dave, as I suspected but good to get confirmation.

That pulseview display looks brilliant! I need to get that working here...is it a plugin you've made?

D
by dominicbeesley
Mon Feb 12, 2018 9:57 pm
Forum: hardware
Topic: bbc master RDY
Replies: 3
Views: 232

bbc master RDY

I notice that the Master uses the 65c12's RDY line, and is connected to the PBC(IC21) and the IOC(IC15). Not having access to my Master at the moment I can't have a poke to see what this is used for - is it to do the 1MHzE cycle stretching or is it something more fancy?

D
by dominicbeesley
Mon Feb 05, 2018 1:56 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1258

Re: R65C02 in a Beeb

No but the cpu might be affected by trying to read data from RAM before it is ready!

D
by dominicbeesley
Mon Feb 05, 2018 12:37 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1258

Re: R65C02 in a Beeb

Thanks for measuring that, the IC14 signal doesn't seem to have moved that much relative to the phi2 edge so it looks like its that relationship between the memory clocks and phi2?

I'll have a try of my stock of cmos parts tonight if I get a chance

D
by dominicbeesley
Mon Feb 05, 2018 12:03 am
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1258

Re: R65C02 in a Beeb

Out of interest did you (please could you) measure how much this: a) shifts phi1/phi2 relative to the ram clock* b) shifts the databuffer enable relative to the ram clock I suspect they might be shifted by different amounts due to the CMOS part having different thresholds? * I'm not sure what to use...
by dominicbeesley
Sat Feb 03, 2018 1:52 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1258

Re: R65C02 in a Beeb

This is bringing back memories now of my trials with getting a 65816 to work. I think its not just that the timings are changed but that the CMOS parts are more sensitive to clock transitions and translate the slow and noisy clock into several far too fast clocks which cause incorrect behaviour. You...
by dominicbeesley
Fri Feb 02, 2018 8:07 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1258

Re: R65C02 in a Beeb

Could it be marginal write hold times or other timing issues...it's what I'm battling with at the moment along with limits for the relationship between phi0/phi2 for stable operation.
by dominicbeesley
Fri Feb 02, 2018 8:00 pm
Forum: hardware
Topic: ADFS source code
Replies: 5
Views: 299

Re: ADFS source code

I had that set to false but it seems the tube detect code still uses TSB with that set =FALSE?

If you do update it let me know, the sources in v1.50.zip seems to have more commentary which will help with porting! Should both yours and Hoglet's produce the same output?

D
by dominicbeesley
Fri Feb 02, 2018 12:54 pm
Forum: hardware
Topic: ADFS source code
Replies: 5
Views: 299

Re: ADFS source code

Thanks Hoglet,

I'll use yours as a baseline - the v1.50.zip on MDFS had promising looking build options for building all the various versions from a single source but looks like it only actually did 1.50!

D
by dominicbeesley
Fri Feb 02, 2018 10:36 am
Forum: hardware
Topic: ADFS source code
Replies: 5
Views: 299

ADFS source code

Hello all, I've been looking for the canonical assembler sources for the latest builds of the ADFS roms. What is at http://mdfs.net/Info/Comp/BBC/ADFS/ in v150.zip looks promising but doesn't seem to work for me - for instance if I build the IDE/BBC flavour it falls over on a TSB instruction that's ...
by dominicbeesley
Thu Feb 01, 2018 9:54 am
Forum: hardware
Topic: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket
Replies: 34
Views: 1395

Re: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket

Yes, please! That would be very useful for me - I have an FX2 but would like to also get my pizero working!

The FX2 board was what I thought you were sending me originally!

D
by dominicbeesley
Wed Jan 31, 2018 10:49 pm
Forum: hardware
Topic: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket
Replies: 34
Views: 1395

Re: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket

I'm glad you got it working! Are you running this alongside a real 6502 or does the BGA board contain a 6502 soft-core? On my side, for once I've taken my own advice and it's worked. I reduced all the slew rates on the lattice board to SLOW and the drives to 4ma/LVTTL - that effected an immediate im...
by dominicbeesley
Wed Jan 31, 2018 6:30 pm
Forum: hardware
Topic: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket
Replies: 34
Views: 1395

Re: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket

It might be worth bunging on a load more caps if you can and then adding an earth strap...a short length of solder braid from one ground to another. You're not using a lot but FPGAs switch very fast and so can induce a lot of ground bounce. It might be also worth trying reducing the pin drive and sl...
by dominicbeesley
Wed Jan 31, 2018 1:25 am
Forum: hardware
Topic: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket
Replies: 34
Views: 1395

Re: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket

Sorry, I've been getting my part numbers mixed up, I've just received my Spartan 6 board (ordered from China months ago) a Max V board a EPM1270 board and a MachXO board... Re grounds, I think a couple more would be good just to get a low-impedance connection to the daughter board. I'm now connected...
by dominicbeesley
Wed Jan 31, 2018 12:08 am
Forum: hardware
Topic: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket
Replies: 34
Views: 1395

Re: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket

That would be great. I've got my attempt "nearly" working it will boot and get my mmc menu loaded but most games crash before they go far. I had to add an extra couple of ground leads from the machxo to the motherboard - The leads from the cpu board to the machxo are nearly 1 foot long (a ...
by dominicbeesley
Tue Jan 30, 2018 10:14 am
Forum: hardware
Topic: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket
Replies: 34
Views: 1395

Re: Electron 6502 desolder / socket pics

Sounds good, Is the code for this on GitHub, I hooked up a 10M8 breakout board to the cpu board. What I've done is hacked the CPLD on your CPU board a little to: a) make phi1/phi2 using buffer delays for non-overlap b) pass RnW/IRQ/NMI/etc from expansion back to cpu socket c) put back cpu_is_externa...
by dominicbeesley
Mon Jan 29, 2018 9:45 am
Forum: hardware
Topic: Electron 6502 desolder / socket pics + Max 10 FPGA in CPU socket
Replies: 34
Views: 1395

Re: Electron 6502 desolder / socket pics

Have you more details of what this is and what it's trying to do....

I nearly got my machxo CPU working last night on a model b. It seems to be running ok but nothing on screen... I need to strip down and check I've not broken the machine when I accidentally left it running with no clock for an hour
by dominicbeesley
Sun Jan 28, 2018 12:07 pm
Forum: hardware
Topic: BBC Circuit diagram
Replies: 10
Views: 431

Re: BBC Circuit diagram

I'm still interested where you got this from Jannie, I've spotted some differences to my "canonical" one (103,000/C of Issue 9 7/83) it would be good to know any information that could date it. (I've not looked hard, but just now I spotted D4/D5 specified as not fitted on the issue 9 diagr...
by dominicbeesley
Sun Jan 21, 2018 9:10 pm
Forum: hardware
Topic: BBC Circuit diagram
Replies: 10
Views: 431

Re: BBC Circuit diagram

Ooh that's much clearer than the one I've been using. Where did you source the hard copy?

PS: thanks for sharing!
by dominicbeesley
Tue Jan 16, 2018 6:25 pm
Forum: hardware
Topic: BBC B Running slow
Replies: 18
Views: 849

Re: BBC B Running slow

The other thing to check is how clean the reset is. I had some problems on or off my beebs with reset not cleanly transitioning. That gave a weird multiple reset
by dominicbeesley
Mon Jan 15, 2018 10:35 pm
Forum: hardware
Topic: BBC B Running slow
Replies: 18
Views: 849

Re: BBC B Running slow

I commented suspecting stray interrupts (of either flavour). But then I read the fault description again and deleted my comment. I'm struggling to see any way that stray interrupts would suddenly clear up the moment you entered BASIC! Unlikely but it could be all sorts of pickup most been motherboa...
by dominicbeesley
Mon Jan 15, 2018 4:53 pm
Forum: hardware
Topic: BBC B Running slow
Replies: 18
Views: 849

Re: BBC B Running slow

Has it had DFS in the past. If s9 is snipped it might be spurious NMIs. What other roms ate fitted?
by dominicbeesley
Fri Jan 12, 2018 9:02 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3433

Re: SpectROM - Speccy emulator for the Pi co-pro

Excellent work rob...another triumph
by dominicbeesley
Wed Jan 10, 2018 5:44 am
Forum: hardware
Topic: Myelin's fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 1080

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

I'll have a go at hacking something together myself and let you know results before asking you to commit to anything. Even without DMA I need to work out if polling or NMIs would be better for block transfers. I'd say for a general purpose serial port some sort of disable-able interrupts would be in...
by dominicbeesley
Tue Jan 09, 2018 10:40 pm
Forum: hardware
Topic: Myelin's fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 1080

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

I'm mega-busy this week so won't have a chance for any in-depth tests of speed on the serial link but I will think about this when I'm on holiday. I was going to have several transfer modes for the DMA 1) halt processor, seize the bus, transfer one byte in/out every cycle 2) NMI, trap NMI before cpu...
by dominicbeesley
Tue Jan 09, 2018 12:52 am
Forum: hardware
Topic: A blitter for the beeb?
Replies: 49
Views: 2524

Re: A blitter for the beeb?

Thanks Simon. Much appreciated
by dominicbeesley
Tue Jan 09, 2018 12:47 am
Forum: hardware
Topic: Myelin's fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 1080

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

Thanks Phil, I started experimenting around the same area. I first tried just removing the twiddly status register stuff in .ReadData itself: that didn't do anything noticeable but I've not been measuring accurately (counting cursor flashes while as ~96K module loads in 5 chunks). I see what you're ...
by dominicbeesley
Mon Jan 08, 2018 11:40 pm
Forum: hardware
Topic: Myelin's fast serial port/SD card adapter for the 1MHz Bus
Replies: 25
Views: 1080

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

I'd vote drop anything that is JIM / PAGE FD related, as unearthed in a recent thread JIM is broken and two devices can't really share it. If you could get two COM ports working that would be worth more to me than anything else! I've had a quick test this past hour and it seems to work well (barring...