On 2019-11-07 19:04, rescue wrote:
I have one of these, it has 2 jumper blocks, JPR2 (4 3
'settings'... looks to probably latch each of the 4 high or low) and
JPR3 (12 on/off jumper positions).
It also has a JPR1 which would be a 3 pin header and it is strapped
by wire to position 1-2.
Would love to figure out how the IO port and IRQs are configured.
Card has no BIOS, so unlike a WD1002A-FOX there won't likely be any
jumpers to set drive type. (I'm not having much luck with that card
in a Tandy 2500 SX... but that's a completely different issue).
Hopefully someone has or knows where there are some docs on the
I'd imagine I could figure out some by probing which ISA pins various
jumpers connect to..... but any jumper settings that control chips
decoding logic will be far more difficult to determine.
I spent an hour or more tracking traces/etc on the PCB. I believe I
have fully figured out the settings.
Here they are for anyone ever needing them.
The card is a Tecmar PC 500K/1MEG FLOPPY CONTROLLER 941393 REV A
It also has a paper sticker on it that says WANGTEK 24128-001
Here is what I figured out:
JPR3 is a 12 position header, jumper pairs are 1+13, 2+14, 3+15, 4+16,
Clearly, the DRQ and DACK #s should be set identical, so 1+13 and 4+16
for DMA1, etc...
JPR2 sets the I/O port address, there is no numbering to these pins.
There are 3 rows of pins. The upper row is ground, the bottom row is
and you jumper the middle row to U (up, ground), or D (down, +5V)
3F0 is standard PC primary floppy controller, 370 is for the secondary
I believe my card was set wrong, as there was no jumper for the first
triple of JPR2, leaving the comparator inputs that compare to SA7 on the
ISA bus indeterminate.
I'll now be seeing if I can get this operating as a secondary floppy
No guarantees any of this is right, but I worked out some of the
connections. The IRQ and DMA stuff was easy. The port addressing was
determined mostly via a 74LS688N
so I had to track down the P0-7 and Q-07 inputs and determine what I/O
port address the corresponding JPR2 jumpers were setting.
Oddly, SA0 through SA9 have fingers on the card. So, not sure if this
thing would respond to multiple addresses based on the settings of
SA10-SA19. This is where my ignorance of the ISA bus and PC
architecture leave me scratching my head, but regardless, I think the
above settings are correct.