I have recently received a CPC6128 and had the problems to connect 2x3,5" drives to the CPC (internally and externally). The main problem was, that i've could not find detailed informations about the wireing and the signals (even here on CPCWIKI.EU) This is my contribution to this issue. I will add the wireing for the DDI-1 soon.

= Signal names and connector numbering =
<pre>Floppy | Signal description
connector | for standard floppy 34 pin connector 34pin |
----------+---------------------------------------------------
1..33 | GND
2 | /DS (density select 1=low desnity / 0=high density
4 | NC
6 | NC
8 | /IND index
10 | /MED0 motor enable drive 0
12 | /DRV1 drive select 1
14 | /DRV0 drive select 0
16 | /MED1 motor enable drive 1
18 | /DIR direction select
20 | /STEP head step
22 | /WDAT write data
24 | /WGAT write gate
26 | /TRK0 track 0
28 | /WPT write protect
30 | /RDAT read data
32 | /S1 side 1 select
34 | /RDY ready (or /DSKCHG) depending on model or drive configuration</pre>
 

 
<pre>CPC-CD201 | Signal description internal
| for CPC internal floppy 26 pin connector
| (numbering from amstrads repair manual)
----------+---------------------------------------------------
1..25 | GND
2 | /IND index
4 | /DRV1 drive select 1
6 | NC
8 | /MED1 motor enable drive 1
10 | /DIR direction select
12 | /STEP head step
14 | /WDAT write data
16 | /WGAT write gate
18 | /TRK0 track 0
20 | /WPT write protect
22 | /RDAT read data
24 | /S1 side 1 select
26 | /RDY ready (or /DSKCHG) depending on model or drive configuration</pre>
 
<pre>CPC-PL-9 | Signal description external
| for CPC external floppy 34 pin connector
| (numbering from amstrads repair manual)
---------+--------------------------------------------------
2..34 | GND
33 | +5V
31 | +5V
29 | +5V
27 | /IND index
25 | NC
23 | /DRV1 drive select 1
21 | +5V
19 | /MED1 motor enable drive 1
17 | /DIR direction select
15 | /STEP head step
13 | /WDAT write data
11 | /WGAT write gate
9 | /TRK0 track 0
7 | /WPT write protect
5 | /RDAT read data
3 | /S1 side 1 select
1 | /RDY ready (or /DSKCHG) depending on model or drive configuration
</pre>
 
<pre>Translation from CPC-PL-9 via Centronics 36 pin connector to floppy connector 34pin
===================================================================================
(flat cable / crimp variant view)

+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---- GND
| | | | | | | | | | | | | | | | |
Floppy connector 34pin 33 31 29 27 25 23 21 19 17 15 13 11 09 07 05 03 01 NC
Centronics 36pin 18 17 16 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01
Amstard CPC-PL-9 02 04 06 08 10 12 14 16 18 20 22 24 26 28 30 32 34 NC
**++**++**++**++**++**++**++**++**++**++**++**++**++**++**++**++**++**++
Amstard CPC-PL-9 01 03 05 07 09 11 13 15 17 19 21 23 25 27 29 31 33 NC
Centronics 36pin 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19
Floppy connector 34pin 34 32 30 28 26 24 22 20 18 16 14 12 10 08 06 04 02 NC
| | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | | +-- NC
| | | | | | | | | | | | | | | | +------ +5V
| | | | | | | | | | | | | | | +---------- +5V
| | | | | | | | | | | | | | +-------------- +5V
| | | | | | | | | | | | | +------------------ /IND
| | | | | | | | | | | | +---------------------- NC
| | | | | | | | | | | +-------------------------- /DRV1
| | | | | | | | | | +------------------------------ +5V
| | | | | | | | | +---------------------------------- /MED1
| | | | | | | | +-------------------------------------- /DIR
| | | | | | | +------------------------------------------ /STEP
| | | | | | +---------------------------------------------- /WDAT
| | | | | +-------------------------------------------------- /WGAT
| | | | +------------------------------------------------------ /TRK0
| | | +---------------------------------------------------------- /WPT
| | +-------------------------------------------------------------- /RDAT
| +------------------------------------------------------------------ /S1
+---------------------------------------------------------------------- /RDY

**/++ Flatcable signal</pre>
 
<pre>External floppy connector PL-9 to floppy connector 34pin
========================================================
(flat cable / crimp variant view)

Note: Disconnect wire 03-35-32 /S1 if there is no support
by the operating system or if you want to
use a side selector switch which is connected to the
floppy drive.

PL9 CEN PCF SIGNAL
01 36 34 /RDY
02 18 33 GND
03 35 32 /S1
04 17 31 GND
05 34 30 /RDAT
06 16 29 GND
07 33 28 /WPT
08 15 27 GND
09 32 26 /TRK0
10 14 25 GND
11 31 24 /WGAT
12 13 23 GND
13 30 22 /WDAT
14 12 21 GND
15 29 20 /STEP
16 10 19 GND
17 28 18 /DIR
18 10 17 GND
19 27 16 /MED1
20 09 15 GND
21 26 14 NC
22 08 13 GND
23 25 12 /DRV1
24 07 11 GND
25 24 10 NC
26 06 09 GND
27 23 08 /IND
28 05 07 GND
29 22 06 NC
30 04 05 GND
31 21 04 NC
32 03 03 GND
33 20 02 NC
34 02 01 GND
-- 19 -- NC
-- 01 -- NC
</pre>
 
<pre>Internal floppy conntector CD201 to floppy connector 34pin
==========================================================
(flat cable / crimp variant view)

Note: Disconnect wire 25-31 /S1 if there is no support
by the operating system or if you want to
use a side selector switch which is connected to the
floppy drive.

CD201 PCF SIGNAL
26 34 /RDY
25 33 GND
24 32 /S1
23 31 GND
22 30 /RDAT
21 29 GND
20 28 /WPT
19 27 GND
18 26 /TRK0
17 25 GND
16 24 /WGAT
15 23 GND
14 22 /WDAT
13 21 GND
12 20 /STEP
11 19 GND
10 18 /DIR
09 17 GND
08 16 /MED1
07 15 GND
06 14 NC
05 13 GND
04 12 /DRV1
11 GND
10 NC
03 09 GND
02 08 /IND
01 07 GND
06 NC
05 NC
04 NC
03 NC
02 NC
01 NC</pre> <pre>Floppy drive issues

======================
This cables work for drive which are jumpered as drive 1 or DS1. This is normally the default selection on drive delivery. Also make sure you find a drive which has the possibility to generate a ready signal instead of a disc change signal.

</pre>
 
<pre>Disk issues
============
If you intend to use a HD drive, make sure to close the HD detection hole on your disk. </pre>