Re: [CommodoreOne] 1541 superdrive?? / Re: Update on my projects

From: Ruud Baltissen (
Date: 2001-08-01 07:55:09

Hallo Lyndon, Frank,

L:> Get me some Hardware and we'll talk.
F:> Can you please send me the wiring diagram (or text)?

In the top right corner of
you'll find the complete IDE-connector.

AFAIK all known versions of the 1540 and 1541 can be used. But the
boardcodes for the various ICs vary from version to version. Therefor I will
refer to the 6522 handling the floppydisk as #1 and the to the 6522 with the
free A-port and handling the IEC-bus as #2.

Both the A-ports will be used to handle the datalines: port A of #1 will
handle the databits D0..7, port A of #2 will handle D8..15. Port B of #1
will handle the controllines:
- PB0 : addressline A0
- PB1 : addressline A1
- PB2 : addressline A2
- PB3 : the original LED
- PB4 : CS0
- PB5 : CS1
- PB6 : IOWR
- PB7 : IORD

Add the three resistors coded R4, R5, R6. R2 and the LED D1 are optional.

As you can see the original LED is still used as well. The IDE-interface has
a pin to connect a LED to but this LED will only light up when the HD is
active and therefor cannot be used to flash codes or whatever.

When cutting lines, makes sure the one to the SO-input of the 6502 is cut as
well. The connect the input to +5V through a 10K resistor. We don't need it
right now but the resistor enables us to use it in the future.

When using a 1541-II, check if there is a connection between PA0 and PA1 of
the 6522#2. This is an inheritence of the days that the 1541C had a track 0

For the programmers:
 incase of a write:
  1) feed the databus with data
  2) select address and CSx-line
  3) pull IOWR (L)
  4) pull IOWR (H)
  5) pull CSx (H)
 remark: have to find out if 2+3 and 4+5 can be done in one step.

 incase of a read:
  1) select address and CSx-line
  2) pull IORD (L)
  3) read data
  4) pull IORD (H)
  5) pull CSx (H)
 remark: have to find out if 1+2 and 4+5 can be done in one step.

For the people interested in the C64-version: the keyboard-CIA will handle
the data: port A D0..7, port B D8..15. The userport handles the controllines
like above. But in this case we don't need a LED as we have a big screen to
tell us there is an error.

That's all folks! IMHO it is so simple that no SCH is needed for the moment.

  / __|__
 / /  |_/     Groetjes, Ruud
 \ \__|_\

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