plotters again

[Brent Hilpert]

Tony Duell wrote:

> My guess, and it's only a guess, is that it works something like this :
> At power-up, if the 9815-mode line is asseeted, the plotter goes into
                                                              ^^^^^^^^^
> listen mode (the HPIB talk/listen modes can be controlled from the
  ^^^^^^^^^^^      ^^^^
> plotter's microcontroller, this is also used for self-tests on the HPIB
> interface, as it is on the 7245...). The 9815 talks and sends it data.
                                                ^^^^^     ^^^^^    ^^^^
> If the poltter gets a command that should output data (say a digitise
> command), it goes into talk mode automatically and sends said data. The
                         ^^^^ ^^^^ ^^^^^^^^^^^^^     ^^^^^      ^^^^
> 9815 side of things knows it's just sent such a command and goes into
> listen mode to recieve said data.
  ^^^^^^^^^^^    ^^^^^^^      ^^^^

Good for you, you've finally got it.
As I said previously: un-addressed talk/listen HPIB-style data transfer.