Search found 183 matches

by troed
Tue Mar 20, 2018 6:45 am
Forum: MEMBER BLOGS
Topic: Boosting STFM: 16MHz bus, 64MHz Shifter
Replies: 116
Views: 6539

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: 26
Views: 1237

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: 116
Views: 6539

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: 116
Views: 6539

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: 2950

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: 2950

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...
by troed
Sun Mar 11, 2018 11:10 am
Forum: PSU (power supplies)
Topic: Atari Falcon PSU
Replies: 10
Views: 358

Re: Atari Falcon PSU

It's the brown 400V I'm thinking about ... I usually see those on recaps ;) But yeah, the Q.C-sticker does look like something from Atari.
by troed
Sun Mar 11, 2018 11:00 am
Forum: PSU (power supplies)
Topic: Atari Falcon PSU
Replies: 10
Views: 358

Re: Atari Falcon PSU

Looking at the type of caps on that PSU - are you certain that this PSU hasn't been recapped already by a previous owner?
by troed
Sat Mar 10, 2018 8:11 pm
Forum: MEMBER BLOGS
Topic: Boosting STFM: 16MHz bus, 64MHz Shifter
Replies: 116
Views: 6539

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

So this RESET thing ... I've been working on it on and off throughout the day, but the results confuse me. If I measure RESET on the CPU with the LA, it's pretty much what I expect. I'm surprised at how it bounces high and low, but at least it stays high when the computer runs. If I now connect the ...
by troed
Sat Mar 10, 2018 7:48 am
Forum: MEMBER BLOGS
Topic: Boosting STFM: 16MHz bus, 64MHz Shifter
Replies: 116
Views: 6539

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

(So yesterday before dozing off to sleep I seem to have ordered some 48MHz oscillators and GAL22V10 ... ;))

I do believe a DE duty cycle of XXXX..XXXX..XXXX..XXXX..XXXX for a 32MHz MMU and Shifter clocked at 48MHz would work.