[Coco] FDD 26pin to 34pin

[Chester A Patterson]

OK. I figured as much. Most signals are no problem, DS0, DS1 and DS3
(HS) have where to go... (please be patient, I'm learning and
remembering, fast) I see now why we can only have up to 4 SS FDDs or 3
DS FDDs. However, where to send the Coco DS2 signal on the 26pin FDD?
And I guess the READY signal remains N/C?

Thanks.
/Chester
>>>>> <<<<<
The floppy drives use a bus topology. All signals go to all drives.

-Mike

-----Original Message-----
From: Mike Pepe [mailto:lamune at doki-doki.net] 
Sent: Monday, August 07, 2006 5:56 PM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] FDD 26pin to 34pin

Chester A Patterson wrote:
I think now I've got it gentlemen.
Passing this info for your far more knowledgeable review and advice.

Coco FDD interface (Disto)  PC FDD interface  FDD 26pin (Citizen OSDC)
------------------------------------------------------------------------
1	Gnd			    Gnd		    +5V
2	N/C			    Density Select    INDEX
3	Gnd			    Gnd		    +5V
4	N/C			    N/C		    DRIVE SELECT 0
5	Gnd			    Gnd		    +5V
6	N/C			    N/C		    DRIVE SELECT 1
7	Gnd			    Gnd		    +5V
8	INDEX			    INDEX		    READY
9	Gnd			    Gnd		    +5V
10	DRIVE SELECT 0	    MOTOR ON DRIVE 0  MOTOR ON
11	Gnd			    Gnd		    N/C
12	DRIVE SELECT 1	    DRIVE SELECT 1    DIRECTION SELECT
13	Gnd			    Gnd		    Gnd
14	DRIVE SELECT 2	    DRIVE SELECT 0    HEAD STEP
15	Gnd			    Gnd		    Gnd
16	MOTOR ON		    MOTOR ON DRIVE 1  WRITE DATA
17	Gnd			    Gnd		    Gnd
18	DIRECTION SELECT	    DIRECTION SELECT  WRITE GATE
19	Gnd			    Gnd		    Gnd
20	HEAD STEP		    HEAD STEP	    TRACK 00
21	Gnd			    Gnd		    Gnd
22	WRITE DATA		    WRITE DATA	    WRITE PROTECT
23	Gnd			    Gnd		    Gnd
24	WRITE GATE		    WRITE GATE	    READ DATA
25	Gnd			    Gnd		    Gnd
26	TRACK 00		    TRACK 00	    SIDE 1 SELECT (HS)
27	Gnd			    Gnd
28	WRITE PROTECT	    WRITE PROTECT
29	Gnd			    Gnd
30	READ DATA		    READ DATA
31	Gnd			    Gnd
32	DRIVE SELECT 3	    HEAD SELECT (HS)
33	Gnd			    Gnd
34 	N/C			    DISK CHANGE

The two FDD 26pin I have are from a TANDY 1400LT, they have the 0123
switch onboard but the manual, from which I took the above info,
mentions not the switches that I could find (they were set to 0 and 1
when I yanked the drives) But the 1400 has a provision to add an
external FDD and at the flip of a switch (on the side of the 1400) to
make the external FDD either A or C drive.

So, I guess my lingering question is: where/how do I connect the Drive 
Select lines to the 26pin FDDs?

Thanks.

/Chester