80-Bus News

  

May–June 1984 · Volume 3 · Issue 3

Page 45 of 51

available as CTRL/W, and LF is available as CTRL/J. Whether [ \ ] and { | } are shifted or unshifted depends on the Keyboard option. With these changes, the full ASCII character set is still available from the keyboard.

b) Parallel printer support

Upon power-up or reset, the PIO is initialized. Printer output is activated by the U command, and deactivated by the N command. This is made possible by a change in the workspace initialisation, $UOUT will initially point to the printer driver routine. Initial contents of $UOUT: C3 CB 04

c) New NAS-SYS commands

Two new NAS-SYS commands are provided:

L
PRINT

The contents of the accumulator are sent to the printer, using the printer driver routine. Please note that this command is independent of the N and U commands, working always. If the accumulator contains code £0A, data will not be sent to printer, code £0D will be sent to the printer as £0A. The printer must be on line, or the routine will make the Nascom hang up. This command is best used as a subroutine call in programs:

£DF £4C PRINT     Sends contents of A to printer.

F aa bb cc dd ....       SEND ARGUMENTS TO PRINTER

Up to ten hexadecimal arguments following the command are converted to 8-bit data and sent to the printer. If arguments >£FF are specified, only the least significant byte is sent. Please note that this command is independent of the N and U commands, working always. The printer must be on line, or the command will make the Nascom hang up. As this command uses the printer driver routine, arguments of £0A will be ignored, and arguments of £0D will be converted to £0A. This command is very useful for sending control codes to the printer, for example to activate or deactivate emphasized or enlarged print mode.

Using modified NAS-SYS and printer with standard Nascom firmware

a) NAS-SYS

Printer on – U command
Printer off – N command

The user is in direct communication with the printer, that is, everything that is typed on the keyboard will be sent to the printer. Line feeds are ignored. Carriage returns will be sent as line feeds.

b) NASPEN

For the P command to function, the printer reflection must be changed:

101D    DF 4C C9   SCAL "L   RET

c) DEBUG

DEBUG uses the NAS-SYS $UOUT jump, and therefore turns off the printer when started. Use these DEBUG commands to control the printer:

Printer on – :C 04CB
Printer off – :C C143

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