TECH TIPS

GRAPHICS 9 PICTURE LOADER

By Ray Irish

You can quickly and easily load and display your Graphics mode 9 pictures with this simple loader program. When you RUN it, the program displays a menu listing picture files on the disk in drive 1. To load a picture, press the corresponding letter on the menu. Once the picture appears onscreen, you can "tint" the picture by pressing any key. Press [RETURN] to go back to the menu.

This program loads pictures in the 62-sector ComputerEyes format. The menu only lists picture files with the appropriate. PI9 extenders (see line 19).

By changing constants to variables, using low line numbers and heavy line compacting, I was able to dramatically reduce this program's run time and memory use. It really shines when used with an autoboot - that way you can even delete DUP.SYS and fit an extra picture on your data disks.

Listing: 8bit/GR9PICLO.BAS Download

P:R: CONNECTION HELP

By David Mitschelen

ICD's P:R: Connection is a popular printer and serial interface for the Atari 8-bit. It connects your Atari to the rest of the world - but sometimes that connection can go bad. The following tips may help you track down any problems you may be having with your P:R: Connection.

(The ANTIC staff was not able to verify that all these wiring tips are correct. As always, ANTIC is not responsible for any damage that may result from hardware modifications mentioned here. Also, be aware that opening or modifying any device may void its warranty, if any.)

If your printer doesn't work when attached to the P:R: Connection using the standard cable, check to make sure the cable has the shielding wire or foil grounded to the printer chassis (but not to the interface). Many printers won't require the connection, but my bargain-basement NEC PR105 just sat there without it.

If your printer saves paper but makes a mess of your message by printing over the same line, you need a carriage return with line feed. Software will often handle the problem during setup, or you can change a dip switch in the printer. But if it's a common problem for you, the easiest solution may be to change the jumper inside the P:R: Connection. There are two internal jumpers. One disconnects the parallel interface if it causes problems when using the serial connection, and the other changes the default carriage return without line feed into a carriage return with line feed.

The serial port on the P:R: Connection is used for connecting to a modem or to another computer through a null modem cable. Null modems seem to cause more problems than modems. A null modem is a handy way to transfer text or data files between non-compatible systems or disk formats. It does away with the need for a modem and telephone line, and allows faster sending rates than many modems can handle.

The only problem is getting the null modem to work, since the normal wires have to be crossed: send goes to receive, etc. The bare bones send/receive/ ground connection won't work if your terminal program, such as 850 Express, checks for a carrier signal. The standard null modem configuration from Radio Shack and ANTIC (July 1984, page 46) connected all the pins, but didn't work with my NEC Starlet. Noticing a short remark in the P:R: Connection manual that the Clear To Send (CTS) should be connected to the Data Set Ready (DSR), I rewired my null modem as shown below. I can now successfully transfer data in both directions. I hope one of the three configurations below, for connecting a 25 pin RS-232 to an Atari 9-pin interface, will bring you success, too.

P:R: CONNECTION - $89.95

ICD, 1220 Rock Street, Rockford, IL 61101. (815) 968-2228. Also requires $14.95 ICD cable.

25-Pin RS-232	Atari 9-Pin Interface
	Radio Shack	ANTIC's	Mine
1&7 (GND) 2 (XMT) 3 (RCV) 4 (RTS) 5 (CTS) 6 (DSR) 8 (DCD) 20 (DTR)	5 (GND) 4 (RCV) 3 (XMT) 8 (CTS) 7 (RTS) 1 (DTR) 1 (DTR) 2 (DCD) & 6 (DSR)	5 4 3 7 (RTS) 8 (CTS) 1 2 (DCD) 6	5 4 3 2 (DCD) 1 (DTR) 1 7 (RTS) 6 & 8 (CTS)