Real Time Clock on Cassette Write/Sense lines

From: Jim Brain <>
Date: Sat, 11 Feb 2012 00:33:04 -0600
Message-ID: <>
Anyone see issues with wiring up a I2C-based (DS1307-type) RTC to the 
cassette port with SCK on WRITE and SDA (data) on sense?  Looking at 
schematics, READ is often hooked to CA1 or similar read-only pin, but 
SENSE appears to be on a GPIO on all CBM machines I found.  Obviously, 
the RTC would not work if the buttons were pushed on the player, but are 
there other concerns?

My other idea is to put SCK on MOTOR and put SDA on the WRITE line, 
which looks to be a GPIO.  But, I was afraid such constant cycling of 
the MOTOR line with a datasette present might cause it's own issues.


Jim Brain

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Received on 2012-02-11 07:00:03

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