rapidly changing a single output bit, in software, at the
appropriate times. The technique is a simple loop with eight
OUT and SHIFT instruction pairs for each byte. Input is more
interesting. And
full-duplex (doing input and output at the
same time) is one way to separate the real hackers from the
Bit bang was used on certain early models of
Primecomputers, presumably when
UARTs were too expensive, and on
technique is now (1991) coming back into use on some
RISCarchitectures because it consumes such an infinitesimal part
of the processor that it actually makes sense not to have a