Deunan wrote on 2023-02-20, 22:51:
DCG is to configure READY or DISK CHANGE on pin 34. PC needs DISK CHANGE but without documentation I can't say if the jumper is in correct position or not. You can try the other position.
Here's a page for NEC FD1157C, these are somewhat similar (but 1157C is HD drive): https://wiki.applesaucefdc.com/doku.php?id=dr … ves:nec_fd1157c
Note these drives have head loading solenoid and thus the number of jumpers (and combinations) is higher than on more simple drives where head is lowered by turning the door latch. I will be cleaning 1157C in few days, I know it works but it's super dirty to the point that stepper motor can't move head properly. So I need a lot of time for deep cleaning, probably during weekend. If you can't figure it out by then I can make a photo of my jumpers, might help.
I found a roughly good description for the FD1157C (in Russian) but it's for the Spectrum ZX and I'm not too sure if it applies to PC x86 ?!
http://zxbyte.ru/fdd_nec_fd1155c.htm
It describes all the switches and who does what, but even with the settings from there, I get some weird error in the BIOS Test on a sample of the format test that the response timed out.!?
Floppy spins on boot, LED seems to work normally, set as drive B: 360kb (as per spec) but still won't read or write!
I will shoot a video tomorrow because I don't have time left.
byte13_147.jpg
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I did not find detailed information on all the jumpers, so I give a description of those that I managed to determine based on the documentation of similar drive models and on the "poke" method 😀
Description of jumpers:
DRIVE - drive selection (Drive A - Drive D). Accordingly, jumper 0 sets the drive as Drive A, jumper 1 - as Drive B, etc.
USE - control of the magnet to lower the head onto the disk.
The jumper must be set to position 2. When set to position 1 or there is no jumper, the electromagnet does not work, so there will be no reading / writing to the disk.
DCG - selection of the signal assignment at the output of the 34th interface connector:
1 - a drive ready signal is generated (this signal is required for operation on some ZX-Spectrum clones, but for the bulk of the clones, the signal does not matter, because it is simply not connected anywhere);
2 - the Disk Change signal is generated (when a disk is changed in the drive). To connect to a PC on the drive, you need to install this jumper!
HDE - DD/HD mode selection.
1 - tightly turns on the HD mode (360 rpm of the disk), while the position of the DEN jumper does not play any role;
2 - includes the ability to work in both DD and HD. Switching between these two modes is carried out by a signal on the 2nd pin of the drive's interface connector. The polarity of the switching signal is set by the DEN jumper:
DEN - determines the polarity of the HD / DD mode enable signal:
1 - HD at log.1 on the 2nd pin of the interface connector, DD - at log.0 on the 2nd pin of the interface connector;
2 - HD at log.0 on the 2nd pin of the interface connector, DD - at log.1 on the 2nd pin of the interface connector;
3 - HD mode is always on.
MON - determines the conditions for spinning up the disk in the drive:
1 - by Motor On signal;
2 - subject to head loading (HS);
3 - by the signal Drive 0 - Drive 3.
In practice, the drive normally works on the ZX-Spectrum only when the jumper is set to position 1.
HS - head loading state selection (?):
When the drive is working with the ZX-Spectrum, the position of the jumper (1 or 2) does not play any role.
LED - control of the light-emitting diode on the face of the drive. There are two jumpers here:
1 and 4 - the LED lights up when the head is loaded (Head Load);
1 and 5 - the LED lights up when the head is loaded (Head Load) + active Drive Select signal;
2 and 4 (as well as 2 and 5) - the LED lights up when the Drive Select signal is active;
3 and 4 - the LED lights up when the Ready signal is generated;
3 and 5 - the LED lights up when the Drive Select + Ready signal is active;
LUS - the purpose of the jumper is unknown. In this instance of the drive, the jumper was hard-soldered to position 1.
JP - closes the drive case and circuit ground.
In this instance of the drive, the jumper was not used at all (the pins for it were not soldered).
MX - the purpose of the jumper is unknown.
There is an unsoldered DX jumper next to it.
Based on the foregoing, to connect a drive to the ZX-Spectrum, you need to set the following jumper configuration:
Drive - set to your liking, depending on what "number" the drive is connected to. If it is the only one, then we put it in position 0;
HS - don't care.
DCG - it's better to set it to position 1 in case you have a cunning drive controller that suddenly takes into account the drive's ready signal during its operation;
HDE - set to position 2;
DEN - to position 2 if your BDI controller does not send anything to the 2nd pin of the drive interface connector (or sends log.1 there). If the controller outputs log.0 to this pin, then set the jumper to position 1.
MON - set to position 1 (disc spin-up by Motor On signal);
LED - put two jumpers in positions 2 and 5 (the LED on the face of the drive will light up according to the Drive Select signal).
Jumpers can be set, for example, as in the photo below (the drive is set as Drive A):