[net.micro.trs-80] Model I Printer Drivers

chuckp@ncoast.UUCP (Chuck Poulton) (12/07/84)

   Assuming once again that the printer driver is at fault and
not the hardware, here's a little bit of information that might
be helpful:

   First of all, the May 1981 issue of the TRS-80 Microcomputer
News has an article detailing the operation of both the Model I
and III printer drivers.  It says that although "there are times
when the computer will send line feeds to the printer, the
computer just won't let you do it."  Besides sending an
occasional line feed after a carriage return, it also sends
line feeds to simulate a top-of-form.

   Secondly, if it turns out that you need a printer driver
that sends what you tell it to send this 4 byte program should
do it:
	LD A,C
	JP 05B4H
Simply store the program (79H,C3H,B4H,05H) somewhere in
protected memory, and point the two bytes at 4026H to this
driver.  Besides allowing line feeds to get send correctly,
this driver will also keep the ROM driver from changing
bytes that are meant to be sent to the printer for graphics.
Unfortunately, however, BASIC messes things up by changing
a couple of characters before they get to the printer driver
(although I'm not sure which ones). 

  If anyone needs more information or another kind of printer
driver (I have a friend with a half dozen) I'd be glad to
do what I can.
   
		Chuck Poulton
		...!decvax!cwruecmp!ncoast!chuckp