Can all registered uses please login, even just for a few minutes..
It helps build a picture where our "good traffic" is coming from..
Thanks :)

Unused GSTMCU wire (STe) and HD7.0

Update your old 720k to a 1.44 drive etc.
Post Reply
User avatar
Pacman
Posts: 256
Joined: Mon Aug 28, 2017 12:56 am
Location: Norway

Unused GSTMCU wire (STe) and HD7.0

Post by Pacman »

Having had my STe in storage I've forgotten a few things such as loose wires along with a bunch of add-ons and modifications.

I noticed a loose wire soldered to the motherboard underneath the power supply and located the connection being to pin 2 (CLK) of U400 (GST MCU chip). If I'm not mistaken this is a 16 MHz clock signal as shown here (scroll down to the right-hand side photo entitled "Fitting to STe").
I did put an Exxos HD version 6 into my STe, but think I messed it up and therefore bought an Exxos HD version 7.0 to replace it (which is now clearly visible in my STe).

So..... I think the loose "CLK" wire is just a left-over from the version 6 board, and no longer needed with the version 7, as it has a built-in 16 MHz oscillator which takes care of that, right?
I can't think of anything else the wire has been used for... or can be used for later. Any thoughts on this? Should I just leave it for other uses, or might it only cause potential interference problems if it gets close to other cables or parts of the motherboard?
STe | MonSTer with dual IDE-CF memory card adapter | NEC Multisync 1990SXi | ST_ESSC | RSVE | Link '97 | Sony HD floppy drive/AJAX controller | Exxos HD floppy module | Battery-backed Ricoh realtime clock module | Discovery cartridge | C-Lab Unitor-2 | C-Lab Export | C-Lab Combiner | C-Lab Steady Eye | C-Lab Human Touch | Unicorn USB

💧Are you a good person? 💧Living Waters
User avatar
Badwolf
Site sponsor
Site sponsor
Posts: 3065
Joined: Tue Nov 19, 2019 12:09 pm

Re: Unused GSTMCU wire (STe) and HD7.0

Post by Badwolf »

Pacman wrote: Tue Nov 05, 2024 11:30 pm So..... I think the loose "CLK" wire is just a left-over from the version 6 board, and no longer needed with the version 7, as it has a built-in 16 MHz oscillator which takes care of that, right?
I can't think of anything else the wire has been used for... or can be used for later. Any thoughts on this? Should I just leave it for other uses, or might it only cause potential interference problems if it gets close to other cables or parts of the motherboard?
If it's not connected anywhere and you're happy with your machine working, I'd remove it.

You've got an unterminated 16MHz antenna there. It's unlikely to be a good thing.

BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark
User avatar
Pacman
Posts: 256
Joined: Mon Aug 28, 2017 12:56 am
Location: Norway

Re: Unused GSTMCU wire (STe) and HD7.0

Post by Pacman »

Badwolf wrote: Thu Nov 07, 2024 12:32 pm If it's not connected anywhere and you're happy with your machine working, I'd remove it.

You've got an unterminated 16MHz antenna there. It's unlikely to be a good thing.
Good point! And probably applicable for any loose wires left dangling.

My Exxos HD/DD floppy drive module (7.0) appears to have all its wires connected. The 3 external wires attached are P1, P2 and D0.
D1 isn't used.
20241107-153332_PB070002.jpg
20241107-153332_PB070002.jpg (402.12 KiB) Viewed 2395 times
I can't locate any pin marked with something resembling a 16MHz input, so is it safe to assume everything is connected as it's supposed to and I can remove the unterminated 16MHz "antenna" wire?
(unfortunately the STe isn't ready for use at the moment, or else I'd just try it out and see).
STe | MonSTer with dual IDE-CF memory card adapter | NEC Multisync 1990SXi | ST_ESSC | RSVE | Link '97 | Sony HD floppy drive/AJAX controller | Exxos HD floppy module | Battery-backed Ricoh realtime clock module | Discovery cartridge | C-Lab Unitor-2 | C-Lab Export | C-Lab Combiner | C-Lab Steady Eye | C-Lab Human Touch | Unicorn USB

💧Are you a good person? 💧Living Waters
User avatar
Darklord
Site sponsor
Site sponsor
Posts: 1635
Joined: Wed Sep 20, 2017 1:41 pm
Location: Prestonsburg
Contact:

Re: Unused GSTMCU wire (STe) and HD7.0

Post by Darklord »

Here's the 3 wires coming off of my Exxos HD mod installation. You can see
where the wires go. The far left one goes to the floppy drive mech. itself:

(older picture - I touched it up a bit after this)


20240811_162954.jpg
20240811_162954.jpg (307.32 KiB) Viewed 2389 times
Welcome To DarkForce! www.darkforce.org "The Fuji Lives.!"
Atari SW/HW based BBS-Telnet:darkforce-bbs.dyndns.org 1040
User avatar
Pacman
Posts: 256
Joined: Mon Aug 28, 2017 12:56 am
Location: Norway

Re: Unused GSTMCU wire (STe) and HD7.0

Post by Pacman »

Thanks.
It appears to be the same as with mine except the two thick wires (red and white) don't go to U8 (Yamaha YM-2149) but rather to the two connection points of W301 (as shown in the Exxos installation page's photo for HD module version 6).
The third wire goes to the floppy drive (to the HD select switch as far as I remember. It's been a while since I opened up the drive).

So.... it appears I have no need to the 16MHz wire (I can't think of any other modification or add-on which needs it either) and can safely remove it.
STe | MonSTer with dual IDE-CF memory card adapter | NEC Multisync 1990SXi | ST_ESSC | RSVE | Link '97 | Sony HD floppy drive/AJAX controller | Exxos HD floppy module | Battery-backed Ricoh realtime clock module | Discovery cartridge | C-Lab Unitor-2 | C-Lab Export | C-Lab Combiner | C-Lab Steady Eye | C-Lab Human Touch | Unicorn USB

💧Are you a good person? 💧Living Waters
Post Reply

Return to “FLOPPY DRIVES KITS & UPGRADES”