3.5" NEC FD3238T/H FFC pinout

[Dropcheck]

I've been looking for the pinout of the NEC FD3238H/T slim line 3.5" floppy drive FFC for awhile now.  I've been unable to locate the specific pinout, but I have a couple of generic conversations between other similar slim line floppy drives.  So far I haven't been able to get the drive led to light on the adapter I've developed for my XF551 boards. I've tried two NEC drives so far with the same result.  So I suspect my pinout is not correct rather than the drive itself.   

 

This is what I have.

[TGB1718]

Is the LED on the floppy drive or one you have fitted one on an adaptor.

 

In the floppy, it's the drive select line that lights the LED, so if you have another outside of the drive, you need to

use the drive select line (with a suitable buffer) something like a 7407 to switch the LED on.

[Dropcheck]

1 hour ago, TGB1718 said:

Is the LED on the floppy drive or one you have fitted one on an adaptor.

 

In the floppy, it's the drive select line that lights the LED, so if you have another outside of the drive, you need to

use the drive select line (with a suitable buffer) something like a 7407 to switch the LED on.

It's the led on the drive itself.  I'm assuming that all it's circuitry is on the drive itself.  Just need to correctly connect the drive select signal to the proper pin on the drive connector.  That's why I was asking for the specific pinout of the NEC drive connector.  ?

 

I am getting power to the drive.  It is momentarily spinning up when a disk is inserted and I power cycle the drive.  But no lighting of the led on the drive.  

[TGB1718]

I seem to remember in the long distant past (but I may be wrong) that some drives were set to be drive 1, can/have you tried

connecting the drive select to the drive 1 connection

[manterola]

I guess that is correct. Try to redirect the ds0 from the controller pcb to ds1 of the drive. I did it using a floppy cable and twisted it. I was using a teac slim drive, but the concept is probably the same: the drive just has a ds input, so you need to feed that input with ds0

Edited October 20, 2019 by manterola

[Dropcheck]

The problem seems to be the conversion between a 26 pin FFC connector on the drive and the older IDE 34 pin connector.  I know the proper wiring for the older IDE 34 pin connector.

There doesn't appear to be any jumper/resistor for DS0/DS1 on the drive.  I think on the newer 3.5" SLIM LINE FFC 26pin drives it was assumed the drive was DS0.

 

This is another pinout I found:

 

Edited October 20, 2019 by Dropcheck

[BillC]

7 hours ago, TGB1718 said:

I seem to remember in the long distant past (but I may be wrong) that some drives were set to be drive 1, can/have you tried

connecting the drive select to the drive 1 connection

All later PC floppies are factory configured as DS1, DIP jumpers have been replaced with solder jumpers on most modern mechanisms since this rarely needs to be changed. 

This use of DS1 started with the IBM PC in 1982, using the twisted floppy cable to configure A: and B: automatically. IBM did this so techs wouldn't have to configure drive select for the second drive, which reduced assembly time.

 

 

 

[+kheller2]

https://www.slideshare.net/mobile/SergioBetancur4/floppy-micro-conector

 

and yeah wouldn’t you need to hard wire line 12 on the 34 to pin 4 on the 26?

[_The Doctor__]

it's normally pin 14 or pin 10 of the normal connector to pin 4 of the mini... depending on if the ribbon has the twist in it or not...

[+kheller2]

Doc is right.  Basically you want XF DS0 to floppy DS(1). Right? XF only enables DS0 and most drives are hard jumpered  to DS1.  But you know this, it’s the mini cable giving you issue. 

[Dropcheck]

On the normal 34 pin IDE connector for the XF551 Atari jumpered the motor control signal to both pins 10 and 16.  That worked for the 5.25" drives which at that time were usually set as DS0.

 

When 3.5" drives came along, they were normally set as DS1 or the second floppy in a two floppy drive PC setup.  So that's why we have to change them to DS0 to work with the Atari.  In theory you could also cut the trace between 10 and 16 on the IDE connector and then simply jumper pin 12 to pin 16 and achieve the same result.  Right?

 

Now on the newer 26pin FFC connector is pin 4 serving as the DS0/DS1 pins(10/12) on the IDE connector?

 

***Tried jumpering FFC connector pin 4 and 10, drive is NAK on DIR D1: command from SpartaXDOS 4.48

 

***Tried pin 4 and 10 FFC connector separated drive, is NAK on DIR D1: command from SpartaXDOS 4.48

 

I am getting the normal short spin up of a XF551 drive using HyperX B firmware, so the power and gnd signals are good. 

Edited October 21, 2019 by Dropcheck
new info

[1050]

Coming out of the 1772 on the XF551, MO is inverted by a NAND gate and then split off to the DS0 pin as well.

 

kheller2's link shows both /MOTE and /DRVS as negative logic by that forward slash, but the XF551 is positive to turn on the busy light and the motor. This "new" type of drive requires inverted logic on those pins?

[+kheller2]

The original source for the digram I posted is here: https://old.pinouts.ru/HD/26pin_microfloppy_pinout.shtml

There is also a warning about it not being for Toshiba drives.

I have no idea if this document is correct

 

[Dropcheck]

8 hours ago, 1050 said:

Coming out of the 1772 on the XF551, MO is inverted by a NAND gate and then split off to the DS0 pin as well.

 

kheller2's link shows both /MOTE and /DRVS as negative logic by that forward slash, but the XF551 is positive to turn on the busy light and the motor. This "new" type of drive requires inverted logic on those pins?

I don't think it's a new type of drive, just that the connection between the 'motherboard' and the drive itself evolved from the previous standard IDC-34 connector to the reduced pin count connector and a flat flexible cable to save space in laptops etc.

[1050]

True and true, my observation is explained by noting that 1772 is positive out for MO but needs to be inverted for even 5.25 and of course 3.5 drives. And then my not understanding that part clearly before I posted last. This is where I learn something new to me and I thank you all for that.

 

But:

On 10/20/2019 at 5:35 PM, Dropcheck said:

  I think on the newer 3.5" SLIM LINE FFC 26pin drives it was assumed the drive was DS0.

I would always assume the opposite, that any and all 3.5 drives were set to be DS1 and eventually they were all hardwired to be DS1 to save OEM assembly time. 4 drive floppy computers never were a major portion of the market and two floppy drives weren't popular either. Your connection needs to be at the 34 pin cable shown in post 6 as a jumper from 16 to 12. Disconnect pin 10 there.

 

On 10/21/2019 at 7:39 AM, Dropcheck said:

In theory you could also cut the trace between 10 and 16 on the IDE connector and then simply jumper pin 12 to pin 16 and achieve the same result.  Right?

I do believe so, yes. I've done exactly that under the board of the XF551 for use with DS1 set 3.5 drives and it worked a treat. Posted a photo of the work done in the group but have lost the link to it. Feeling pretty useless about that but it is what it is.

 

On 10/21/2019 at 7:39 AM, Dropcheck said:

Now on the newer 26pin FFC connector is pin 4 serving as the DS0/DS1 pins(10/12) on the IDE connector?

My opinion is sort of. The combined /DRVS signal is now busy light on, which also turns on head read/write and index hole circuits. Suitable for ONLY one floppy drive computers is the change employed.

 

On 10/21/2019 at 7:39 AM, Dropcheck said:

***Tried jumpering FFC connector pin 4 and 10, drive is NAK on DIR D1: command from SpartaXDOS 4.48

Should have worked if 34 pin connector is the XF551 board connector. And it hasn't already been modified for SD1 use under the board (maybe?). It does get confusing, best of luck in any case.

 

 

[+kheller2]

Hmm....

https://hxc2001.com/download/floppy_drive_emulator/Slim_SD_HxC_Floppy_Emulator_User_Manual_ENG.pdf

page 16 says DS0