80-Bus News

cable doesn’t trail up stairs to the back room. Admittedly, my cable is only a couple of feet long but it was all I could find when the printer arrived.

EPRINT Listing.

The commented listing of EPRINT should be relatively simple to follow but I shall explain some areas such as setting up the PIO and printer. EPRINT by the way stands for Epson Printout Ready In No Time or alternatively Extra Playing Round In Nascom Trauma.

NAS-PEN, ZEAP etc.

When executed, the first questions asked involve what software you want ta run the printer with. Dependent an the replies, the vectors held in RAM for the ZEAP and NAS-PEN output routines may be set to OUTCHA, the character output routine. Unfortunately NAS-DIS has no RAM vector and so can only use the printer (as with BASIC) by setting OUTCHA as the user output routine. Needless to say, NAS-PEN or ZEAP must be initialised before executing EPRINT or they will just overwrite the vectors when ‘cold started’. If ZEAP is selected, then the printer AUTO FEED EXT line will have to be disabled. This is because while the ZEAP sends a CR and LF, the printer will automatically do a LF on reception of the CR. Hence two LF’s and double line spacing, very nice but paper is expensive. NAS-PEN, and software using the user output routine will only send a CR and so AUTO FEED EXT is left low unless ZEAP is selected. A value stored in D is used to set this line later on.

Setting Printer Status.

Several questions are asked relating to the way you require the printer to be configured. Many more variations could be catered for (column width, print size etc.) but it becomes tedious setting too many whenever you switch on or start using some different software. You will usually configure the printer the same way and anyway codes can be embedded in the text to set anything else.

As mentioned above AUTO FEED EXT is controlled by the level of that line, all the other features are set by sending control codes to the printer. Before any codes are sent to the printer, it is reset by holding INIT low for longer than 60 microseconds. There is no need to compensate for CPU clock speeds (2/4 MHz. etc.) as all timing is done assuming a 4MHz. clock and all delays may be exceeded without effect.

The length of page is set by ESC C nn (nn is a hex. value 0<nn<127.).

The paper end detector is set on by ESC 9 or off by ESC 8. This stops the buzzer going off while using single sheets which is annoying because it is LOUD and buzzes for ages.

The printer is told to skip over the perforation at the end of each page by ESC E 6. The 6 tells it to skip 6 lines which with normal spacing is one inch. Note that the DIL switches have been left to cause the printer to initialise in the NO SKIP condition.

Having set all these conditions, the printer status is tested and suitable messages output to the screen.