[BBC-Micro] Floppy cable switch

Pete Turnbull pete at dunnington.plus.com
Sun Jan 3 13:44:36 GMT 2010

On 03/01/2010 13:29, Mark Usher wrote:

> I wanted to add a switch to my dual disc drives to swap the drive IDs round.
> Ie. Drive 0/2 becomes 1/3 and vice versa.
> As would be expected the drives are jumpered ID0 and ID1. Is it possible to
> put a switch in the floppy cable to swap the two around similar to the twist
> in a PC cable?

Sure, you just need a switch to change over DS0 and DS1.  That's not 
what a PC cable twist does, BTW.

What you need to do is cut the lines for DS0 (pin 10) and DS1 (pin 12) 
in the cable, insert a double-pole double-throw (DPDT) switch:

BBC end                                            drive end
                   o-------+------------------ 10 ------------- 10
10 ------------o---       |
                   o----+--)------------------ 12 --------------12
                        |  |
                   o---/   |
12 ------------o---       |

The red stripe on the cable is pin 1, so 10 is the tenth wire from that 

Pete						Peter Turnbull
						Network Manager
						University of York

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