Search found 61 matches

by guus.assmann
Mon Mar 11, 2019 7:12 pm
Forum: TWEAKS & FIXES
Topic: TT Rom access speedup
Replies: 32
Views: 1032

Re: TT Rom access speedup

No, I've not mounted that capacitor.
But it doesn't hurt.

BTW: It's possible to mount a switch in series with the grey cable.
This makes it possible to have the standard speed.
May be needed in some cases, altough I've not encountered that yet.

BR/
Guus
by guus.assmann
Mon Mar 11, 2019 6:26 pm
Forum: TWEAKS & FIXES
Topic: TT Rom access speedup
Replies: 32
Views: 1032

TT Rom access speedup

Hello,

Here's a picture of the 2 diodes on pin 15 and 16.
The grey wire goes to the Eprom-CS at pin 22.
That's all there is to it.

BR/
Guus
by guus.assmann
Fri Mar 08, 2019 5:04 pm
Forum: TWEAKS & FIXES
Topic: TT Rom access speedup
Replies: 32
Views: 1032

TT Rom access speedup

Just now I've also tested with the 1N5819 diodes. And that also works just fine. Then I removed the CF-cards so the TT would boot from floppy. Attached are the result files. Quite similar to the pictures in previous post. I've only looked at the Rom speed while I compared the before and after. The a...
by guus.assmann
Fri Mar 08, 2019 10:12 am
Forum: TWEAKS & FIXES
Topic: TT Rom access speedup
Replies: 32
Views: 1032

TT Rom access speedup

In a TT with Eproms, the OE line will be jumpered to GND, so OE is not used in the selection of the Eprom. And it does need CS to work. I have been looking at the data sheet of the 1N58189 but cannot find a recovery time. That may be an important factor. I have already had the TT not booting when I ...
by guus.assmann
Fri Mar 08, 2019 8:01 am
Forum: TWEAKS & FIXES
Topic: TT Rom access speedup
Replies: 32
Views: 1032

TT Rom access speedup

Hello, I am very sorry for the mixup I caused. I confused 28 pin and 32 pin devices. So it is indeed pin 24 that's the CE for the Eprom that I used. I'll try with 1N5819 diodes, hopefully today. As for the Gembench, I took the most recent version I could find. And next I'll try without any extra pro...
by guus.assmann
Thu Mar 07, 2019 5:41 pm
Forum: TWEAKS & FIXES
Topic: TT Rom access speedup
Replies: 32
Views: 1032

TT Rom access speedup

Hello Josh, The Eproms from ThunderStorm are fast enough, mine are 150nS. And 1N5819 should work, most important is the voltage drop. ( <0,8V) However, CS is pin 20 and not pin 22. Pin 22 is OE and that's permanently connected to GND trough one of the jumpers. I have not seen any slow Eproms yet. Bu...
by guus.assmann
Thu Mar 07, 2019 2:22 pm
Forum: TWEAKS & FIXES
Topic: TT Rom access speedup
Replies: 32
Views: 1032

TT Rom access speedup

Hello, The how and why is very simple. 8-) Once you know it. Back in the days that the TT was designed, the Eproms where quite expensive and not so fast. 200nS or less. Also, Atari may have anticipated using Mask-Roms. Those were kind of slow also. To still use the slower devices, wait states were t...
by guus.assmann
Wed Mar 06, 2019 2:42 pm
Forum: TWEAKS & FIXES
Topic: TT Rom access speedup
Replies: 32
Views: 1032

TT Rom access speedup

Hello, So far I've tried this sucessfully on 3 different TT machines and it works well. It only takes two diodes, Germanium or Schottky (Bat 48). Connect the anode of one diode to XDS0 and a second diode to XDS1. These signals can be found on the ST-Ram board pins 15 and 16 of the C row, connector t...
by guus.assmann
Thu Feb 28, 2019 6:01 pm
Forum: MONGREL EDITION (version 2)
Topic: ST-IDE-ROM Dev Board v1 - BETA Testers
Replies: 403
Views: 6129

ST-IDE-ROM Dev Board v1 - BETA Testers

Hello,

Please put me on the list as well.

BR/
Guus Assmann
by guus.assmann
Fri Feb 01, 2019 3:48 pm
Forum: FLOPPY DRIVES KITS & UPGRADES
Topic: Internal Gotek/FlashFloppy and external disk drive
Replies: 13
Views: 1276

Re: Internal Gotek/FlashFloppy and external disk drive

Hello, An Internal floppy is selected on wire 10, that's connected to DS0 select from the Atari. The external connector is connected to the second floppy select from the Atari. To use the internal cable, the D1 line from the Atari should be connected to wire 12 in the flat cable. Then a drive set as...