Search found 235 matches

by troed
Fri Mar 30, 2018 4:57 pm
Forum: TWEAKS & FIXES
Topic: Hissing and whistling in the STe audio output
Replies: 46
Views: 2293

Re: Hissing and whistling in the STe audio output

Analyzed a third sound capture from a video that had been uploaded to youtube. The same ~2600Hz peak and harmonics is found there, so I'm beginning to become quite certain that this is indeed the well-known "STE high pitched whine". As to the cause ... well. I don't think it's age related (I remembe...
by troed
Mon Mar 26, 2018 1:51 pm
Forum: MEMBER BLOGS
Topic: Boosting STFM: 16MHz bus, 64MHz Shifter
Replies: 125
Views: 8451

Re: Boosting STFM: 16MHz bus, 64MHz Shifter

So are you running the shifter on 96Mhz to get the MMU at 48MHz ? Or just running the MMU at 48Mhz on its own clock ? Did you get anywhere with the shifter overheating in mono mode ? MMU at 32MHz, Shifter at 48MHz, pulsing DE at a 4/6 duty cycle which will cause them to get back in sync. However, s...
by troed
Sun Mar 25, 2018 10:50 pm
Forum: MEMBER BLOGS
Topic: Boosting STFM: 16MHz bus, 64MHz Shifter
Replies: 125
Views: 8451

Re: Boosting STFM: 16MHz bus, 64MHz Shifter

So the above test was completely wrong, DE didn't get the correct duty cycle. I've rewritten the GAL once again (had to go to a truth table since it became too complicated .. ) and the simulation looks fine now. Will try to find time in the next few days to test it in the real machine (and to patch ...
by troed
Sat Mar 24, 2018 6:35 pm
Forum: MEMBER BLOGS
Topic: Boosting STFM: 16MHz bus, 64MHz Shifter
Replies: 125
Views: 8451

Re: Boosting STFM: 16MHz bus, 64MHz Shifter

Thanks!! I knew there had to be something about the RESET that I overlooked :) A quick fix to still run the GAL, the MMU and CPU clock with RESET only affecting GLUE and MFP brings no improvement. I think it's the MMU and CPU that go into a "deadlock wakeup" on some boots. Will keep pondering. (So ...
by troed
Tue Mar 20, 2018 6:45 am
Forum: MEMBER BLOGS
Topic: Boosting STFM: 16MHz bus, 64MHz Shifter
Replies: 125
Views: 8451

Re: Boosting STFM: 16MHz bus, 64MHz Shifter

So what happens is: - At power on the reset circuit will release the RESET line - The CPU starts executing the TOS - One of the first commands to be executed is "RESET" - Then the CPU will activate the RESET line in order to reset all circuits connected to this line (except the CPU itself) - After ...
by troed
Mon Mar 19, 2018 9:51 pm
Forum: NEWS & ANNOUNCEMENTS
Topic: Lightning VME open Order
Replies: 46
Views: 2652

Re: Lightning VME open Order

I want one for a Mega STE (if there's anything different)
by troed
Sun Mar 18, 2018 10:02 pm
Forum: MEMBER BLOGS
Topic: Boosting STFM: 16MHz bus, 64MHz Shifter
Replies: 125
Views: 8451

Re: Boosting STFM: 16MHz bus, 64MHz Shifter

Where is reset in your code ? I added a simple AND term with RESET on one of the inputs. Since it's an input-only pin, I don't see how it can drive anything low ... (Actually there's an internal pullup so if I don't connect the wire the GAL logic acts as if RESET was high). /* inputs */ PIN 1 = clk...
by troed
Sun Mar 18, 2018 9:41 pm
Forum: MEMBER BLOGS
Topic: Boosting STFM: 16MHz bus, 64MHz Shifter
Replies: 125
Views: 8451

Re: Boosting STFM: 16MHz bus, 64MHz Shifter

Did you try a 1k pull up and a larger cap on reset ? So I got a bit sidetracked by a friend giving me a 520ST last weekend. That model was my original Atari and I just had to piggy-back upgrade its RAM :D I've now added a 2.3 kOhm pullup to RESET, which means it's ~650 Ohm when measured in circuit....
by troed
Sun Mar 18, 2018 1:13 pm
Forum: DISPLAYS & CONVERTERS
Topic: Atari ST Display Basics
Replies: 27
Views: 4237

Re: Atari ST Display Basics

I just checked pin 8 on STE & STM is via 1.2K resistor. Assuming a typo Ingo ? It's "common knowledge" that there are somce machines that don't put out 12V ... but considering even the 520ST schematics has it I'm quite confused as to exactly which those machines would be. 12V / 10mA pin (STE) : On ...
by troed
Sun Mar 18, 2018 10:23 am
Forum: DISPLAYS & CONVERTERS
Topic: Atari ST Display Basics
Replies: 27
Views: 4237

Re: Atari ST Display Basics

[*] GND on ST, 12V on STE I don't think it's this easy. It's GND on 520ST (I have one here), but surely Ube's switches work on a lot of STs and not just STE and it requires 12V edit: So now I'm more confused than before. I just looked at the 520ST schematics and they clearly show pin 8 connected to...