26 Sep
2003
26 Sep
'03
1:53 a.m.
"ed sharpe" <esharpe(a)uswest.net> wrote:
well in looking into the s100 board it seems to
indicate that many many
options could be set under program control, however I am still not sure
it is the at command set...
As I wrote before, it is not. Definitely. No question about it.
It doesn't have ANY command set in the sense of sending it a string
of characters that it would parse as a command. It's a dumb device.
(And there's nothing wrong with that!)
maybe it was some binary sent to it.....
If by "sent to it" you mean "the user program fiddles with bits in
registers using 8080/Z-80 style input and output instructions", yes,
that is how it is controlled. Want it to pick up the phone line?
Set a particular port bit. Clear the bit to hang up (or maybe it was
the other way around). Pulse dial by toggling that bit with the
appopriate timing. Enable the modulator (transmit) with a different
bit, and write to the UART to send bytes. Read a bit of a port for
receive carrier detect. Etc.
I just
wish I checked remember how the micromodem on the apple worked I suspect
the same as the s100 board...
Basically the same though the registers are memory mapped since the
6502 doesn't have I/O instructions.
However, the Apple version has firmware that makes it easier to use.
It's still not the AT command set, but from BASIC you type "IN#2" (if
it was in slot two), then use Control-A as an attention character to
send it commands from the keyboard. I suppose you probably printed a
control-A followed by a command in order to control it from BASIC, just
like printing a control-D followed by a DOS command, but my memory is
fuzzy on that as I mostly programmed it in assembly.