Re: 6502 to 8501: new details

From: Daniele Gratteri (
Date: 2002-02-22 19:05:13

----- Original Message -----
From: "Marko Mäkelä" <>
To: <>
Sent: Friday, February 22, 2002 10:05 AM
Subject: Re: 6502 to 8501: new details

> They should be steady near GND or VCC when nothing is being written and
> the cassette drive is not playing a tape.  When something is going on,
> the readout should change to something between GND and VCC.

When the tape is connected, all the values of the cassette connector
(measured on the bottom of the board) are near 0V or 5V. If I send a LOAD or
SAVE command, the one I found to be the READ is around 2V, another one is
over 6V (!). But maybe it is another signal.
On the bottom of the plus/4 motherboard the cassette connector looks like

(serial here)     oo o      (expansion here)

Do you know what are the READ and WRITE pins? I think I made mistakes...

> A pull-up resistor gives a "default" value of VCC to a signal.  Connect
> a 4700 ohm resistor between VCC and the signal.  When nothing is driving
> the signal down to '0', it'll be held '1' by the pull-up.

Maybe it is a stupid question: a 'pull up' resistor is a normal resistor
simply connected between Vcc and the signal line or I have to ask for a
specific type of resistor?
 / ___|____   Daniele Gratteri, Italian Commodore and Amiga user  / /
| |   |___/   E-MAIL:                 / /
| |___|___\   URL:   \ \/ /
 \____|       IRC: FIAT1100D - ICQ: 53943994                  \/\/

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