[Coco] FDD 26pin to 34pin

[Chester A Patterson]

Hi,

Trying to figure out connecting two 720k 3.5" 26pin FDD to Coco.

Pin connections for 26pin FDD (taken from Tandy 1400LT)

1	Vcc +5
2	Index
3	Vcc +5
4	Drive select 0
5	+5
6	Drive select 1
7	Fcc for analog circuit (what's this?)
8	Ready
9	+5
10	Motor on
11	Reserved
12	Direction
13	Ground
14	Stop
15	Ground
16	Write data
17	Ground
18	Write gate
19	Ground
20	Track 00
21	Ground
22	Write protect
23	Ground
24	Read data
25	Ground
26	Side 1 select

Looking at the standard 34pin connections

1	Ground
2	Density select 1=Low/0=High
3	Ground
4	Reserved
5	Ground
6	Reserved
7	Ground
8	Index
9	Ground
10	0=Motor enable drive 0
11	Ground
12	Drive select 1
13	Ground
14	Drive select 0
15	Ground
16	0=Motor enable drive 1
17	Ground
18	0=Direction select
19	Ground
20	0=Head step
21	Ground
22	Write data
23	Ground
24	0=Write gate (FDD write enable)
25	Ground
26	0=Track 00
27	Ground
28	0=Write protect
29	Ground
30	Read data
31	Ground
32	0=Head select
33	Ground
34	1=Disk change/0=Ready

I'm not sophisticated digitally/softwarewise but do enjoy soldering and
tinkering very much.
I assume the 0/1 drive select lines are two bits, 00=FDD0, 01=FDD1,
10=FDD2 and 11=FDD3. These two 26pin FDDs have the 0123 switch. Some
connections are fairly obvious however I'm stumped at the 0/1 items...
(Head select, Density select, Side select) Where to they connect on the
controller? STOP (pin14) perhaps a typo and should it be STEP?
My plan is to end up having two 5.25 360k (/D0, /D1) and these two 3.5"
720 (D2, /D3)

There's been much here in the last week about FDDs, controllers and High
Density. I find I greatly enjoy this discussion. Does anyone have the
schematics for the FD500, FD501 and FD502 controllers?

Thankyou.

/Chester
Costa Rica