Hello Exxos,
About the disk drives, I have 4 pieces SMD380, 2 have a switch and 3 don't.
And I also have an SMD 300 (From a Falcon) that has a switch.
So far I've checked the ones with the switch. They all have the controller : SF9200-K on them.
The PCB on the SMD300 is different from the other 2 I've seen. A pity. (This has a sticker next to the connector with SMD340 on it as well)
On the SMD380 units there's a jumper JP04. One side is connecter to pin 2 of the connector.
The other side is connected to pin 74 of the controller IC.
I will investigate the other 2 as well, when I have some time.
Question: Does anyone have the data sheet for the SF9200-K?
I can't find it with Google.
BR/
Guus
How to get TOS to see the 1.44MB drives
-
- Posts: 94
- Joined: Sat Sep 23, 2017 8:52 pm
- Location: Ede Netherlands
-
- Posts: 94
- Joined: Sat Sep 23, 2017 8:52 pm
- Location: Ede Netherlands
Re: How to get TOS to see the 1.44MB drives
Hello,
Today I've spent some time with the floppy drives again.
My subjects were 2 Teac FT235 drives, 1,44Mb capable on a PC.
After changing the device ID to 0, they worked in 720k mode.
After some checking, I found that connecting S7 does the trick, I get an output on pin 2.
To make the HD module switch correctly, I had to use an inverter. (This is present on the STE board.)
The only thing was that a 720k disk gave a too high voltage on pin 2. (About 1,6V)
So I soldered a 9k2 resistor between pin 1 and 2. (Now I had 1,0V bearly ok but it worked.)
Now the drive works like a charm, in both densities.
So far, so good.
I decided to assemble the STE and of course put the drive in place.
Still ok, the unit works.
Now put the top cover in place. And test again. Floppy doesn't work anymore.
Same happend to the 2nd drive.
And I don't understand.
Before assembly, I formatted a couple of disks and had no problems.
Any ideas on what may have gone wrong?
BR/
Guus
Today I've spent some time with the floppy drives again.
My subjects were 2 Teac FT235 drives, 1,44Mb capable on a PC.
After changing the device ID to 0, they worked in 720k mode.
After some checking, I found that connecting S7 does the trick, I get an output on pin 2.
To make the HD module switch correctly, I had to use an inverter. (This is present on the STE board.)
The only thing was that a 720k disk gave a too high voltage on pin 2. (About 1,6V)
So I soldered a 9k2 resistor between pin 1 and 2. (Now I had 1,0V bearly ok but it worked.)
Now the drive works like a charm, in both densities.
So far, so good.
I decided to assemble the STE and of course put the drive in place.
Still ok, the unit works.
Now put the top cover in place. And test again. Floppy doesn't work anymore.
Same happend to the 2nd drive.
And I don't understand.
Before assembly, I formatted a couple of disks and had no problems.
Any ideas on what may have gone wrong?
BR/
Guus
Re: How to get TOS to see the 1.44MB drives
Output on pin 2 of what ? The ST knows nothing about density selects on those signals. I would hardware the floppy modules select line to 5V or 0V and try floppies that way. I don't get why you are needing resistors, you should have 5V and 0v, depend on density select switch position on the drive. If anything, you need a pull up to 5V if the switch does not pull up enough on its own.
A pull up sil array on the DMA databus may help..
I went through all sorts of this chaos 20 years ago, I don't remember much, but I know I just had endless issues with various drives. Its why I went with the MPF series and never went back to any others. I think I got one FT235 to try, supposed to be great at error correction etc, cost a lot when new, remember it hardly ever worked. I didn't spend much time working out why as I tested a lot of drives out at the time.
A pull up sil array on the DMA databus may help..
I went through all sorts of this chaos 20 years ago, I don't remember much, but I know I just had endless issues with various drives. Its why I went with the MPF series and never went back to any others. I think I got one FT235 to try, supposed to be great at error correction etc, cost a lot when new, remember it hardly ever worked. I didn't spend much time working out why as I tested a lot of drives out at the time.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.