Bit Banger was Analog modem emulator?

Brian L. Stuart blstuart at
Mon Aug 15 20:44:41 CDT 2005

In message <001e01c5a1fe$ad9c6480$0300a8c0 at downstairs2>, "Michael Holley" write
>An early example of a bit banger serial interface was the Motorola 6800
>MIKBUG Monitor ROM. It used a parallel interface chip (MC6820 PIA) as a
>bidirectional serial interface. It would work at 110 and 300 baud (some
>people clocked it at 1200 baud.)

That reminds me or another little machine from Motorola.  They
called it the Educator II (and was the first computer I ever
owned).  Their cassette interface worked pretty much the same
way.  They toggled a pin on the PIA in software for a simple
FM encoding at 110 baud.  Even the receive side was software.

Brian L. Stuart

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