M200 interfacing

From: John Lawson <jpl15_at_panix.com>
Date: Sun Dec 29 01:45:01 2002

On Sat, 28 Dec 2002, Sellam Ismail wrote:

> That's what I feared. I'll have to come up with an elegant way to decode
> the data.

  I did this once with ASCII paper tape: I made a loop that was triggered
by the 'ready' bit and then sequentially tested each bit in the frame of
7, setting corresponding bits in a register, a kind of stupid software
UART. The problem is to time the loop to be done right as the data bits
are latched, and before the next 'ready' trigger... but the 6522 has
hardware timers, no?

 Once you've latched the card column data, you can store it in a
super-frame that corresponds to the card itself - a 'column frame' and a
'unit record' frame.

  Then decode at your leisure.

Of course I'm a hardware geek - it is more than likely a far more elegant
scheme or algorithm will be offered by Those Who Know These Things.


Received on Sun Dec 29 2002 - 01:45:01 GMT

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