80-Bus News


September–October 1983 · Volume 2 · Issue 5

Page 24 of 67

The subroutine at 3000 would position the cursor on the eighteenth line, first column, assumed to be just below the nicely displayed and formatted data relating to the Record being edited, and the screen from lines 18 to 25 would be cleared. By calling this subroutine before each message then scrolling would be avoided. If RR, CC are set and the routine is called at line 3010, then other cursor positions can be used. The FLAG in line 3020 can be set or not depending whether it is desired to clear the screen from the cursor. Other commands may be used to ‘lock’ the screen. The Gemini IVC manual will give full details.

By placing the cursor on the top of the screen, the existing display can be updated without scrolling or clearing. The effect is much more pleasing, particularly with compiled BASIC, where the speed is such that there is no suggestion of flicker or snow.

Other Odd Bits Of Information.

Wide Printing

As DRH has remarked several times, if all else fails READ THE MANUAL. I didn’t read it carefully enough, but David was quite polite when I bothered him with this problem recently. I wanted to print 233 Chars. wide (Condensed) on a MX100, but I was getting LF’s at the default of 132. I had tried altering the print width in SYS, as well as playing with the switches in the printer, but no BASIC commands did what I wanted. Prompted by Dave, I read the manual more closely, and this revealed an additional command – LPRINT WIDTH, which solved the problem. (This command was described under WIDTH, and not LPRINT in the MBASIC manual. Maybe this is why it was not very obvious.)

Graphics Card Addresses

I recently built the ANIMATION GRAPHICS card to keep my son amused. This card offers reasonably high resolution in 16 colours with relatively easy programming, as well as a number of other features. A major problem for me was that the addresses on the card run from 0 to 29 (including NASIO), clashing with my Nascom I/O card. It is quite easy to move the address range though. Cut the track from IC2 pin 16, to IC7 pin 9. (This is address line 5). Then mount a suitable Inverter chip (e.g. 74LS04) on a small piece of VERO board (about 1″ by 1/2″), and stick this with some double sided white sticky tape to the. component side of the card, near to IC’s 5, 7, having first soldered on 4 short wires for +5v, E, input and output to one inverter circuit. Connect the inverter across the cut track so that it inverts the signal on address line 5. The addresses on the card will now range from 32 to 40. Note that the NASIO O/P will NOT now be correct, and this signal if needed will have to come from elsewhere.

This article was written with the new GEMPEN/​DISKPEN and this new version is a tremendous improvement over the earlier versions. [Ed. – although this article may have been written using PEN, it has since been converted by me into a WordStar file, as I now like to deal with the complete mag. with one word processor, if possible, and WordStar is much more appropriate for major literary works like this!] The ‘HELP’ overlays are very useful, and the commands have been improved so as to render disasters much less likely. Printer support has been vastly improved. The net result is a very useful program. Although not as sophisticated as WORDSTAR, I prefer it for the sort of jobs that I carry out on my machine.

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