Search found 130 matches

by markdryan
Sun Aug 09, 2020 7:15 pm
Forum: general
Topic: Today I built ...
Replies: 81
Views: 10933

Re: Today I built ...

A harlequin 128. In fairness, I didn't build this today or even in a day. It took 3 weekends (about 15 hours in total). It did work first time though, resulting in one of the largest surprises of my adult life. This was a tremendous amount of fun to build and the fact that I was actually able to get...
by markdryan
Fri Aug 07, 2020 2:15 pm
Forum: development tools
Topic: Subtilis: A new BASIC compiler for RiscOS
Replies: 7
Views: 244

Re: Subtilis: A new BASIC compiler for RiscOS

That works. Do you have the source for that, to see how it compares to BBC Basic? MODE 2 LOCAL DIM coords(43) coords() = 0,0,0,2,0,-2,0,4,0,-4,0,5,0,-5, -2,2,2,-2,-2,-2,2,2, 3,3,4,4, 3,-3,4,-4, -3,-3,-4,-4, -3,3,-4,4, 10,-6,-255,-255 VDU [23;8202;0;0;0;] B%=0 FOR C%=0 TO 15 IF C%=8 THEN B%=7 ENDIF ...
by markdryan
Fri Aug 07, 2020 2:10 pm
Forum: development tools
Topic: Subtilis: A new BASIC compiler for RiscOS
Replies: 7
Views: 244

Re: Subtilis: A new BASIC compiler for RiscOS

daveejhitchins wrote:
Fri Aug 07, 2020 1:52 pm
Never thought I'd see the day :shock:
Neither to be honest, did I.
by markdryan
Fri Aug 07, 2020 2:09 pm
Forum: development tools
Topic: Subtilis: A new BASIC compiler for RiscOS
Replies: 7
Views: 244

Re: Subtilis: A new BASIC compiler for RiscOS

Whenever, I tell anyone I'm writing a compiler, the first thing they ask me is how's the performance. So to pre-empt this question let me start by saying the performance is okay but not great. This is understandable really as there's no optimizer yet and the register allocator is, to be polite, a li...
by markdryan
Fri Aug 07, 2020 1:28 pm
Forum: development tools
Topic: Subtilis: A new BASIC compiler for RiscOS
Replies: 7
Views: 244

Subtilis: A new BASIC compiler for RiscOS

You know how it is. You find a load of old computers in your dad's garage. You spent ridiculous amounts of time and money trying to fix them up, connect them to modern displays and find room for them. You then sit down to write that game you always wanted to write as 15 year old but never quite knew...
by markdryan
Fri Aug 07, 2020 10:03 am
Forum: acorn & bbc micro user group (abug) events
Topic: Weeknight 'Virtual' Dev session #0, Thursday 6th August 2020, 7pm - 10pm
Replies: 36
Views: 805

Re: Weeknight 'Virtual' Dev session #0, Thursday 6th August 2020, 7pm - 10pm

> (Spot the connection from Bill Gates to Mark's compiler...)

Excellent. Until now I had absolutely no idea what the Fannkuch benchmark was all about, apart from the fact it was something to do with Pancakes. Now I know. Thanks for the link.
by markdryan
Mon Aug 03, 2020 8:18 pm
Forum: programming
Topic: RISC OS debugger?
Replies: 8
Views: 354

Re: RISC OS debugger?

Here's a screen shot of the DDT running in RPCEmu. Hopefully, this will give you some idea of what the tool looks like and what it can do.
ddt.png
by markdryan
Mon Aug 03, 2020 8:09 pm
Forum: programming
Topic: RISC OS debugger?
Replies: 8
Views: 354

Re: RISC OS debugger?

Hello again, Are we still stuck in the dark ages of *showregs and *memoryi/a? Or are there proper debuggers for ARM assembler now, w/single stepping and arbitrary break points? The DDE comes with an assembly language debugger called DDT which isn't too bad. It allows you to visually step through AR...
by markdryan
Sat Aug 01, 2020 5:16 pm
Forum: 32-bit acorn hardware
Topic: A7000 boot/CMOS RAM issues
Replies: 5
Views: 152

Re: A7000 boot/CMOS RAM issues

It might be worth reading through this thread (https://stardot.org.uk/forums/viewtopic.php?f=16&t=19461) which documents my attempt to fix my A7000's CMOS circuit. My symptoms were different to yours in that I was getting very little voltage on pin 8. This turned out to be caused by some failed capa...
by markdryan
Sun Jul 19, 2020 9:05 pm
Forum: past all-day virtual ABugs
Topic: All-day 'Virtual' Acorn session #6, Saturday 1st August 2020, 9am - 11pm [NOW FULL!]
Replies: 105
Views: 3601

Re: All-day 'Virtual' Acorn session #6, Saturday 1st August 2020, 9am - 11pm

Could you put my name down please? I'll probably won't make the afternoon session but will be able to attend in the morning and evening. Thanks.
by markdryan
Tue Jul 14, 2020 7:49 am
Forum: 32-bit acorn hardware
Topic: StrongARM CPU refurbish
Replies: 8
Views: 482

Re: StrongARM CPU refurbish

I saw it in a YouTube video somewhere, and it worked well on the A5000 (which was so badly corroded that tracks were rusting under the silkscreen). This one perhaps https://www.youtube.com/watch?v=rEhYVyXYU9c? I tried this on my A7000 and it also worked well, although my attempts to solder a new ca...
by markdryan
Tue Jun 09, 2020 5:37 pm
Forum: 8-bit acorn software: other
Topic: Seeking ways to showcase fast second processors
Replies: 57
Views: 2434

Re: Seeking ways to showcase fast second processors

I modified the raytrace program to make it run faster on the Native ARM co-processor lastcol% = -1 MODE2:PROCi FOR I%=0 TO1024 STEP4:FOR J%=0 TO1280 STEP8 x=0.3:y=-0.5:z=0:ba%=3:dx=J%-640:dy=512-I%:dz=1300:dd=dx*dx+dy*dy+dz*dz REPEAT n=(y>=0 OR dy<=0):IF NOT n s=-y/dy FOR K%=1 TOS% px=c(K%,1)-x:py=c...
by markdryan
Mon Jun 08, 2020 9:09 pm
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

After the machine reboots, run this piece of code to see if RISC OS is picking up the I/O chip: <F12> *BASIC SYS "OS_ReadSysInfo",2, TO r0%,r1%,r2% PRINT ~r1% Unfortunately, this is reporting a 0. I tried the same command on my working RiscPC and I get a 1. I'll clean up the SuperIO chip as you sug...
by markdryan
Sun Jun 07, 2020 11:46 am
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

About the floppy. Does the fact that I was actually getting a POST error indicate that the floppy drive might be partially working? Is the superIO chip involved in generating this error?
by markdryan
Sun Jun 07, 2020 10:53 am
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

Well partial success. It looks like C14 was the issue. I removed it this morning and after doing so, measured 4v between pins 4 and 8 of my new CMOS chip with the power turned on. I now measure about 500 ohms of resistance between the two pads of C14. Previously, with the capacitor installed, I was ...
by markdryan
Fri Jun 05, 2020 8:30 pm
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

I'm beginning to suspect C14. This doesn't really have a corresponding component on the RiscPC CMOS circuit diagram but it is connected to R2 on one side and ground on the other. When I try to measure its resistance it doesn't behave like the other capacitors on the board. Seems to measure just unde...
by markdryan
Fri Jun 05, 2020 8:16 pm
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

I'd remove the capacitor and CMOS chip and give that whole area of the PCB a very good clean. After that I'd swap the diode for the sake of ruling it out, and check resistance between the CMOS chip's VCC pad and GND pad on the PCB. I did clean under the capacitor and the CMOS chip before replacing ...
by markdryan
Fri Jun 05, 2020 8:11 pm
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

Looking at the thread, this is the current idea of the circuit, right? Yes, this is what I believe the layout of the CMOS circuit on my A7000 to be. From your measurements it would seem that you have current leaking to 0V somewhere right of R2. Yes. Is it possible for you to carefully lift pin 8 so...
by markdryan
Fri Jun 05, 2020 1:24 pm
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

Will do. I've got a few on order. I've also ordered a replacement for IC7. I'm not making much progress here. I fitted the new CMOS chip last night and re-fitted the battery. Nothing has changed. I still see about .2v between pins 4 and pins 8 of the CMOS chip. Fitting the CMOS chip was a real stru...
by markdryan
Tue Jun 02, 2020 8:05 am
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

Does it do that (fail to boot if you don't hold DEL down) even if you use the reset button? If so, you could be right... I haven't tried with the reset button, but it boots to supervisor with an error from cold boot without the DEL key pressed. I'd get that CMOS chip swapped (remember to clean unde...
by markdryan
Mon Jun 01, 2020 8:53 pm
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

What's the full POST blink code (all 32 bits)? The code seems to be 00010019, so it doesn't look like the "PC-style I/O world detected" bit is set. DEL power on should clear "CMOS RAM unreadable", at least until you flip the power off. Well, unless the CMOS chip is totally chuffed (or the I2C Bus t...
by markdryan
Sun May 31, 2020 10:45 am
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

Before I do anything else, I think I'm going to put the machine back together and check I can still get to the desktop. Hopefully, I haven't broken anything while messing around with the baterry and the capacitors. Oh dear. It seems I have. The machine does still boot but it no longer detetcs the h...
by markdryan
Sun May 31, 2020 9:39 am
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

Yep. I usually use a scalpel (X-acto) with a no.11 blade. I've used a fibreglass pencil but found that it's very difficult to get rid of all the little fibres. They also have this awful tendency of getting just about everywhere... Great. I'll try this. Oh ick. You've got one IC leg, track and via e...
by markdryan
Sat May 30, 2020 7:17 pm
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

So I think the problem here is almost certainly a failed RTC chip, or residual corrosion residue or electrolyte underneath it. Thanks for the great explanations and the diagnosis. I'll order a bunch of these chips this evening. I've used your input and that of DutchAcorn's to update the RiscPC to A...
by markdryan
Sat May 30, 2020 2:11 pm
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

So the new capacitor arrived today. It took me a couple of tries but I eventually managed to get it installed. Unfortunately, it doesn't solve the problem. I still see the voltage drop on side 2 of R133 (R2 on my board). I'm pretty sure the old C70 (C4 on my board) was dead, so it was definitely wor...
by markdryan
Thu May 28, 2020 8:16 am
Forum: past all-day virtual ABugs
Topic: All-day 'Virtual' Acorn session #4, Saturday 6th June 2020, 9am - 10pm - NOW FULL
Replies: 119
Views: 5374

Re: All-day 'Virtual' Acorn session #4, Saturday 6th June 2020, 9am - 10pm

I'd also like to attend. Could you add me to the attendee list as well?
by markdryan
Tue May 26, 2020 9:20 pm
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

My guess now would be that C4 is the culprit here. And yes, a faulty C4 would be a logical cause for a voltage drop. Great. Thanks so much for your help. I'll try to replace C4 and will report back. Am I correct in thinking that this is a 4.7 uF capacitor? Do you happen to know the voltage rating? ...
by markdryan
Tue May 26, 2020 8:33 am
Forum: 32-bit acorn hardware
Topic: A7000 doesn't retain CMOS settings
Replies: 35
Views: 1303

Re: A7000 doesn't retain CMOS settings

You can check if the positive side of the capacitor C4 connects with pin 8 of the cmos chip to verify if it corresponds to C70 on the RiscPC. If so, do you measure a resistance over C4? I think you're correct about C4. The positive side is connected to pin 8 of the CMOS chip and the negative side i...

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