Search found 39 matches

by hicks
Thu Nov 16, 2017 11:50 am
Forum: hardware
Topic: Sounds weird...
Replies: 10
Views: 310

Re: Sounds weird...

I've finally managed to buy an Electron off ebay and hooked it up to the scope to see what a real Electron produces for sound vs my FPGA to get to the bottom of this and, well, the results are unexpected. Based on schematics and reading of the AUG I expected a 244Hz to 62.5kHz range which is what my...
by hicks
Mon Nov 06, 2017 4:32 pm
Forum: hardware
Topic: Sounds weird...
Replies: 10
Views: 310

Re: Sounds weird...

crj wrote:
hicks wrote:Isn't that for the BBC though? The Electron appears to work different?


Well, yes.

In my defence, you didn't actually say you were asking about the Electron! :-p


I expect mind reading :D

Edited original post to mention Electron.
by hicks
Mon Nov 06, 2017 3:49 pm
Forum: hardware
Topic: Sounds weird...
Replies: 10
Views: 310

Re: Sounds weird...

Well, SOUND (OSWORD 7) takes a pitch in semitones. The sound generator IC takes a frequency divisor. The fact that this entails a logarithmic scaling is a clue that SOUND must be doing something . (-8 Isn't that for the BBC though? The Electron appears to work different? Although I assume SOUND is ...
by hicks
Mon Nov 06, 2017 3:38 pm
Forum: hardware
Topic: Sounds weird...
Replies: 10
Views: 310

Re: Sounds weird...

That's what sheet 4 shows I believe. Counter wraps from 0 and the wrap cascades through causing a toggle of SNDSRC and also causing an async reset (in effect loading the counter with the reg'd value, which due to nor gate & reset use looks to only work correctly when the counter has wrapped to a...
by hicks
Mon Nov 06, 2017 2:53 pm
Forum: hardware
Topic: Sounds weird...
Replies: 10
Views: 310

Sounds weird...

Playing around with my Electron FPGA implementation a little and noticed some strangeness with the sound output. The AUG says "FE06" is an 8 bit register that determines the output sound frequency, from 244Hz through to 62.5kHz. Formula used is 1MHz/(16*(S+1)) where S is 0 through 255. Tes...
by hicks
Fri Nov 03, 2017 3:36 pm
Forum: hardware
Topic: Electron cassette speed trials
Replies: 4
Views: 270

Re: Electron cassette speed trials

I'm trying to optimize (snip) 245 seconds - 1200 baud vanilla https://s3-us-west-1.amazonaws.com/8bitkick/PlayUEF/PlayUEF.html 190 seconds - 1200 baud 'turbo' (minimal interblock carrier tones and 1/2 cycle stop bits) https://s3-us-west-1.amazonaws.com/8bitkick/PlayUEF/PlayUEF.html?TURBO=1 I'd be c...
by hicks
Thu Nov 02, 2017 11:07 am
Forum: hardware
Topic: Beeb FPGA
Replies: 378
Views: 22588

Re: Beeb FPGA

Maybe I looked at the wrong one, but the prices on the DE2 board don't look all that cheap? Are you wanting it specifically for home computer/bbc recreation? If so, for that price you could get a Replay board. Although it doesn't have a BBC core for it at the moment porting hoglet's (assuming licens...
by hicks
Tue Oct 31, 2017 7:25 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 20
Views: 964

Re: Electron ULA Schematics

After reading this post it's clear there's still a gap in my understanding of the cassette loading circuits. My implementation will return "A0" rather than "B0" when running straight after load, it only returns B0 after a soft-reset. :-k Reason is, after loading in my version, th...
by hicks
Mon Oct 30, 2017 7:35 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 153
Views: 9990

Re: Proposed: "The Ultimate Electron Upgrade"

always get a 'beep' from after 0, is this the norm? Beep is expected. When it does line 2, it's in sound mode and will be playing back whatever the last frequency loaded into FE06 was. So it looks like from your post after a load, the cassette input counter doesn't remain in reset long term as the ...
by hicks
Mon Oct 30, 2017 2:02 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 153
Views: 9990

Re: Proposed: "The Ultimate Electron Upgrade"

PPS can also try my Iss4s (can'y mind what 6502) & Iss6 (has a R6502AP / R6502-13 / yr84wk33) if need be.... If you can try the issue 4 that would be appreciated. Could you try it by doing a hard-reset, then chain loading the test program and seeing if your results include A0's or B0's. Then do...
by hicks
Mon Oct 30, 2017 11:11 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 35
Views: 1755

Re: Open Source Logic Analyzer Experiments

I should say that the Open Bench Logic Sniffer supports 32 channels, but most cheap logic analyzers only have 16 channels, so I wanted to see how useful these are. Crucially, this does not allow the address bus to be captured. May be a daft idea, but out of interest, would it be feasible to use two...
by hicks
Mon Oct 30, 2017 9:53 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 35
Views: 1755

Re: Open Source Logic Analyzer Experiments

Nice work on the decoder and the detailed write-up =D>

I've been considering getting a logic analyser for a while now rather than making do with a 4 channel scope as a substitute. Now have a starting point :)
by hicks
Sun Oct 29, 2017 4:59 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 153
Views: 9990

Re: Proposed: "The Ultimate Electron Upgrade"

Quick question... If you run the above test program on a real Electron but _do not_ soft reset after loading the program and instead just run it. Do you get A0's rather than B0's in your output? Reason I ask is when a load finishes it seems CDATA will hold a "1" bit in it (due to stop bit ...
by hicks
Fri Oct 27, 2017 8:23 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 153
Views: 9990

Re: Proposed: "The Ultimate Electron Upgrade"

What I see on the scope is after coming out of soft reset, TX Empty goes high->low, then a short time later there's a write to the register "FE04" and ~160ms after that TX Empty goes low->high. It makes sense that 2nd,3rd and subsequent runs of the program to have "80 80" at the ...
by hicks
Fri Oct 27, 2017 10:43 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 153
Views: 9990

Re: Proposed: "The Ultimate Electron Upgrade"

Are the results consistent if you run the program a second time (without pressing break)? If I run a second time (or more) without pressing break the first two values change to 80, the rest are consistent. If there's not differing OS roms, then I guess there's something in my implementation regardi...
by hicks
Thu Oct 26, 2017 11:57 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 153
Views: 9990

Re: Proposed: "The Ultimate Electron Upgrade"

I'm seeing some slight differences between an Issue 4 and Issue 6 Electron.... On an Issue 4 after a soft break I get: >OLD >RUN 0 80 80 80 80 2 80 80 80 B0 4 B0 B0 80 B0 6 B0 B0 80 80 0 80 80 80 80 2 80 80 80 B0 4 B0 B0 80 B0 6 B0 B0 80 80 On an Issue 6 after a soft break I get: >OLD >RUN 0 B0 B0 ...
by hicks
Sat Oct 21, 2017 2:30 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 20
Views: 964

Re: Electron ULA Schematics

I believe I've almost understood how Sheet 4 and 10 works now and for the most part sheet 3. So here's my final take on Sheet 10, cassette input. Sheet 10 DATACNT I'm still not sure on. It enables or disables the ability for the edge detection/CASCOMP to reset the multi counter. The multi counter re...
by hicks
Fri Oct 20, 2017 12:06 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 20
Views: 964

Re: Electron ULA Schematics

Realised that whilst B is used to denote the inverted counterpart of a signal in numerous places on the schematics, on sheet 4, FRQ2 is not actually S8MB. It's using "S8M13" which is the "S16M13" signal divided by two. So it's actually a 615.38kHz signal. That will then (in comm ...
by hicks
Tue Oct 17, 2017 9:36 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 20
Views: 964

Re: Electron ULA Schematics

Dave thanks for uploading those, I'll take a look at them tomorrow and see if they fill in some of the blanks (literally h :lol: ) One thing I've noticed whilst looking at cassette output, sheet 3. There's a 4 bit counter that sets TX Empty to "1" when it has counted from 0 to 10. As long ...
by hicks
Tue Oct 17, 2017 6:30 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 20
Views: 964

Re: Electron ULA Schematics

Interestingly it looks like the "div 13" pin doesn't seem to be present anywhere. I was under the impression the div13 was used in combination with the 16MHz clock to derive an ~1200Hz clock, but it looks like CNTB[8] from sheet 4 is being used for that (B being the suffix for "not&qu...
by hicks
Mon Oct 16, 2017 8:20 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 20
Views: 964

Re: Electron ULA Schematics

Looking more at sheet 4, I'm a little confused by whether the counter is an up or down counter. It looks like the ripple counter is wired ~Q to T which suggests a down counter? On sheet 10 the two and four bit counters are wired Q to T (up counter?) However, when I look sheet 4 where it "loads&...
by hicks
Mon Oct 16, 2017 2:41 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 20
Views: 964

Re: Electron ULA Schematics

It could mean mono tone, as in non varying, maybe for the constant hightone? It does look like MONOINX feeds straight back out as HIGHTONEB. So I was kind of assuming MONOINX is related to high tone detected, but then wonder where the circuit is that does that on the schematics as I don't see anythi...
by hicks
Mon Oct 16, 2017 1:10 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 20
Views: 964

Re: Electron ULA Schematics

I've mostly got a handle on the cassette input schematic now, however I'm still unsure of a few things, if anyone can shed light on these:- ⋅ MONOINX - where is this from? ⋅ MONOOUT - Where does this go? ⋅ S1...S15 - These look to be from Sheet 4 but I'm having a hard t...
by hicks
Sun Oct 15, 2017 10:35 am
Forum: hardware
Topic: Electron ULA Schematics
Replies: 20
Views: 964

Re: Electron ULA Schematics

⋅ Sheet (??) = Processor Address Interface (maybe?) Mark Not sure if that's the name written in the top left but it does appear to be what the sheet is doing. So sheet 13 "Processor Address Interface" it is. In the bottom right there's "ICNTB" That is used on sheet 12 ...
by hicks
Thu Oct 05, 2017 9:09 am
Forum: hardware
Topic: Electron cassette i/o scope trace
Replies: 26
Views: 636

Re: Electron cassette i/o scope trace

hoglet wrote:I'm pretty sure that when the motor is on it outputs a continuous high tone; I can check that today.

Dave


Is that regardless of comm mode setting and whether it's actively reading via CAS IN?
by hicks
Thu Oct 05, 2017 12:21 am
Forum: hardware
Topic: Electron cassette i/o scope trace
Replies: 26
Views: 636

Re: Electron cassette i/o scope trace

One extra question, did any of you notice what CAS OUT did when the electron was just at the basic prompt so neither loading or saving? Was it constant high, low or outputting one pulses? Also same question but during a load operation? I'll check out the other thread in the morning, just about to he...
by hicks
Wed Oct 04, 2017 11:54 pm
Forum: hardware
Topic: Electron cassette i/o scope trace
Replies: 26
Views: 636

Re: Electron cassette i/o scope trace

Assuming 10 bits at least is an actual requirement the ULA enforced, and having thought on this some more, #2 may not be a real problem. When the ula signals TX Empty there's a reasonable amount of time for the 6502 to push out the next byte if it's doing a write to tape sequence. So perhaps #2 neve...
by hicks
Wed Oct 04, 2017 9:04 pm
Forum: hardware
Topic: Electron cassette i/o scope trace
Replies: 26
Views: 636

Re: Electron cassette i/o scope trace

If short gaps are allowed, any idea where the suggestion that a high tone would be a 10 bit sequence came from in the AUG? It's in red which I assume means a recent addition in the draft 3 version so possibly due to a discussion on this forum or another? The Electron test is a good idea, although I'...
by hicks
Wed Oct 04, 2017 8:13 pm
Forum: hardware
Topic: Electron cassette i/o scope trace
Replies: 26
Views: 636

Re: Electron cassette i/o scope trace

I'm working on adding save support now with CAS OUT and have a question regarding hoglet's implementation and notes in the AUG. The AUG states a high-tone is 10 successive 1's, presumably because 9 successive 1's is the longest sequence of ones whilst still being valid data due to a start bit of 0 s...
by hicks
Tue Oct 03, 2017 10:51 am
Forum: hardware
Topic: Electron cassette i/o scope trace
Replies: 26
Views: 636

Re: Electron cassette i/o scope trace

=D> Nice :D. Can you also post a photo of the hardware please [-o< Mark This is a photo of the hardware before I moved it into the mini-itx case shown in the first photo. I didn't have a suitable RS232 straight through cable at the time either, so there's quite a few jumper cables from the serial p...

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