[Coco] FDD 26pin to 34pin

Phill Harvey-Smith afra at aurigae.demon.co.uk
Tue Aug 8 10:18:10 EDT 2006

Chester A Patterson wrote:
> 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?


> 4	N/C			    N/C		    DRIVE SELECT 0
> 6	N/C			    N/C		    DRIVE SELECT 1


> 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,

Could it be that DS0 + DS1 together are a binary encoding of the drive 
number 0..3. The drives on the Dragon Beta prototype machine also had 26 
way connectors and where encoded in this way..... if this was the case 
you would need some sort of encoder between the CoCo and the drive


Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.

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