I need to build a retro machine so that I can access an HDD that required manual input of BIOS parameters. (Yes, I have that information.)

The only ID I can find is ES1O/4A 280695 which yields nothing useful in searches, apart from this group.

The information on the SMC chip is: fdc37c654Qf B9504-B243 6J74560-2A So I'm guessing, by fdc, that it only cares about the floppy drive(s).

ES1O_4A 280695

Most notable features are that the 10-pin connectors are vertical, 10 by 3 pin config block under the IDE connector, and the massive 8 by 5 pin IRQ block.

I'm guessing that the serial ports are functionally configured from "whenever", but I need to disable drive ports to avoid conflict with mobo ports.

Although the primary purpose of this build is data recovery from HDD that can't be recognised through a USB converter, it will also be running my music training software which won't function on anything higher than 486.

ES1O_4A 280695 Back

  • 3
    Could you edit your question to include a photo of the back of the card? Commented Mar 4, 2021 at 6:20
  • 3
    Alternatively, you could look through the multi-I/O cards on TULARC and see if yours is described there. Commented Mar 4, 2021 at 6:31
  • 1
    What is the actual question? Commented Mar 4, 2021 at 18:10
  • 1
    @Armand Indeed, you are right. The SMC chip does not provide ECP, so no parallel port DMA. 8-bit DMA (DMA 1 or DMA 3) is of no use for 16-bit AT IDE (what we know as IDE today), but it might be used for 8-bit XT IDE. The SMC '653/'654 datasheet cites an XT mode that can use DMA, but it seems the XT mode can only be enabled on the soft-configured '653, not on the jumper-configured '654. That card keeps a mystery. Commented Mar 5, 2021 at 21:26
  • 1
    @Stephen Kitt A photo of the back would only reveal the identifiers already supplied. Thanks for the links
    – Treknology
    Commented Mar 7, 2021 at 6:59

2 Answers 2


A bit of googling finds that SMC is "Standard Microsystems Corporation", apparently got renamed at one time to SMSC and finally to "Microchip".

The FDC37C654 is a Super-I/O chip with a floppy disk controller, hard disk controller, two serial ports, and a parallel port. The datasheet can be found e.g. here from this page (not sure how stable this link is).

Configuration pins are

80/81  PCF0/1  Parallel Port Configuration (disable, 3BCH, 378H, 278H)
24/23  SICF0/1  Primary Serial Port Configuration (disable, 3E8H, 2F8H, 3F8H)
91/93  S2CFO/1  Secondary Serial Port Configuration (disable, 2E8H, 3F8H, 2F8H)
83  IDECF  IDE Configuration (disable, enable)
89  TDCCF  Floppy Disk Controller (disable, enable)

I would assume these correspond to 8 of the 10 positions in the config header at the top. If you can read the printing around the config header (remove the bridges if necessary), that should probably identify which is which.

If there's nothing printed on the board, you could try tracing the connections, or trial and error (pick a setting, try to access serial port etc.)

Interrupt pins are:

38 PSPIRQ  Source of Primary Serial Port Interrupt (IRQ3 or IRQ4)
37 SSPIRQ  Source of Secondary Serial Port Interrupt (IRQ3 or IRQ4)
49 FINTR   Floppy Interrupt 
39 PINTR   Parallel Port Interrupt

And I'd assume some of these are part of the IRQ header. I don't see any Harddisk IRQ pin. Possibly the Floppy Interrupt is both for Floppy and Harddisk? Or just labelled "IDE"?

The Harddisk/Floppy DMA is probably available at the DMA config block, but I don't understand the details.

After seeing the photo of the backside: The configuration block on the top routes the middle pins ("2" row) to the resistors directly below, and then from the resistors to the chip on the front side. This means the "1" and "3" row have a constant voltage, representing 0 and 1, and you can figure out which is which by following the traces on the front, if there's nothing else written on the PCB around the configuration block that's not visible in the first picture.

Once you've identified which pin the jumpers go to, the above table will give you the settings to enable and disable the various parts (disabling is two 0 bits).

As the standard serial port configuration is 3F8H and 2F8H, a first guess is that serial ports are enabled in this configuration (because motherboard serials very rare). So then the "1" row means 1, the "3" row means 0. Try moving all jumpers from the top to the bottom, see if the conflicts are gone.

This will also change the two additional jumpers that do not know what they are good for (and I cannot see the front side well enough to trace), so do this at your own risk.

  • If you have a multimeter it would be a simple matter to buzz out the pins in continuity mode to see what goes where. Commented Mar 4, 2021 at 21:43
  • The hard disk/IDE IRQ is set in the jumper block at bottom left - choices are IRQ 14 or 15. The hard disk/IDE DMA is set to DMA1 or 3 in the DMA jumper block at bottom center.
    – Armand
    Commented Mar 5, 2021 at 0:33
  • There's also a game port, so some config pins should correspond to that.
    – Armand
    Commented Mar 5, 2021 at 1:12
  • 1
    Counting the chips on the card, there are 5 level translator chips (2*1488, 3*1489) for the serial ports, the 74LS367 and (there has to be, can't read it) an NE556 for the game port. That's it. So no kind of buffering the data or address lines for the IDE port. That's the cheapest possible design. Commented Mar 9, 2021 at 7:22
  • 1
    This extremely small card amoretro.de/wp-content/uploads/2011/12/… is actually a better IDE interface than the one is the card in this thread, because it buffers IOW/IOR in the 74LS08, and it buffers the low 8 ISA data lines in the 74LS245. Commented Mar 9, 2021 at 7:30

This card is a low-cost model. The PCB is actually designed to take the more modern FDC37C666 chip, but on the card shown in the original post, the older (but mostly compatible) FDC37C654 is equipped instead. The two jumpers labelled FDD (JP5 and JP6) are most likely:

  • FACF - pin 26 - not a configuration pin on the '654. Position doesn't matter
  • FDCCF - pin 89 - floppy disk enable (1-2)/disable(2-3)

The block of 10 jumpers (JP7-JP16) contains (order guessed according to hints from the visible traces. JP8, JP11, JP12 are clearly identified)

  • JP7: IDECF - pin 83 - hard disk enable (1-2)/disable(2-3)
  • JP8: IDEACF - pin 25 - not a configuration pin on the '654. Position doesn't matter
  • JP9: ECPEN - pin 94 - not a configuration pin on the '654. Position doesn't matter
  • JP10: PADCF - pin 58 - not a configuration pin on the '654. Position doesn't matter
  • JP11: PCF1 - pin 81 - parallel port base address
  • JP12: PCF0 - pin 79 - parallel port base address
  • S1CF0/S1CF1 24/23 - first serial port base address
  • S2CF0/S2CF1 91/93 - second serial port base address

JP11/JP12: 1-2/1-2 = 278 ("LPT2"); 1-2/2-3 = 378 ("LPT1"); 2-3/1-2 = 3BC (MDA compatible); 2-3/2-3 = disable

Serial port 1: 1-2/1-2 = 3F8 ("COM1"); 1-2/2-3 = 2F8 ("COM2"); 2-3/1-2 = 3E8 ("COM3"); 2-3/2-3 = disabled. Serial port 2: 1-2/1-2 = 2F8 ("COM2"); 1-2/2-3 = 3F8 ("COM1"); 2-3/1-2 = 2E8 ("COM4"); 2-3/2-3 = disabled.

Do not plug any DMA jumpers. Those signals are only valid in ECP mode of the '666 controller. They serve a different function on the '654, and may cause your computer to misbehave if some software erroneously tries to access a third or fourth floppy drive.

The jumper next to the parallel port can disable two of the six signals generated by U11. Most likely, U11 is part of the game port interface, and drives game port input to the ISA bus. With U11 in the top position (as on the photo), U11 drives only four bits (2 axes, 2 buttons). With U11 in the bottom position, U11 drives six bits, probably two extra buttons for joysticks with actual 4 buttons or special functions like a coolie hat. There seems to be no way to disable the game port completely.

  • Your deductions make a lot of sense. Using "last year's model" parts is a good way to clear out older chips and provide a cheaper entry-level product. Thanks for your effort on this.
    – Armand
    Commented Mar 9, 2021 at 6:29

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .