Xref: utzoo comp.sys.amiga:46193 comp.sys.amiga.tech:8958 Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!mips!apple!oliveb!amiga!cbmvax!valentin From: valentin@cbmvax.commodore.com (Valentin Pepelea) Newsgroups: comp.sys.amiga,comp.sys.amiga.tech Subject: Re: Amiga Parallel Port Keywords: parallel port Message-ID: <9113@cbmvax.commodore.com> Date: 21 Dec 89 00:31:39 GMT References: <3959@rayssdb.ray.com> Reply-To: valentin@cbmvax.commodore.com (Valentin Pepelea) Organization: Commodore, West Chester, PA Lines: 71 In article <3959@rayssdb.ray.com> plw@rayssdb.ray.com (Paul L. White) writes: > > The documentation on the Amiga parallel port is sketchy at best. The > information I seek is with regard to the STROBE and BUSY signals on > the port. Are these signals handled by the hardware or must the signals > be dealt with via software instructions? The STROBE signal is generated by the hardware, while the BUSY signal must be generated by the software. > My father owns a unit which interprets weather satellite broadcast information > and sends the information to a printer. He'd like to be able to connect the > unit to the Amiga 1000's parallel port and write a program to print the image > to the monitor. The documentation makes it very clear that the parallel port > is "usually used for output to a printer." The port's pin-outs are also > provided in the documentation. Unfortunately, although this startling > information is wonderful, it just doesn't change the baby's diapers. All he has to do is make a special parallel cable. Ever heard of null-serial cables? Well, here is how to wire a null-parallel cable: AMIGA SENDING UNIT 1 ---------\ /--------- 1 *STROBE X 10 ---------/ \--------- 10 *ACK 2-9 --------------------- 2-9 D0-D8 11 --------------------- 11 BUSY 12 --------------------- 12 POUT 13 ---------????-------- 13 SEL 14 NO CONNECT +5V 15 NO CONNECT NC 16 WHO CARES *RESET 17 \ / 17 GND ------------------- necessary to connect only one of 17-25 25 / \ 25 GND Under penalty of death, do not connect pin 14. You may not connect the SEL pin to the device and the RING pin on the serial port to the modem simoultaneously. Internally these pins are connected together. >If anyone can provide the information on the parallel port, or even better >if anyone has already written a software module in this vein, it would be >a wonderful Christmas present. "It's in there." It is called the parallel.device. The amiga generates an interrupt internally when the *ACK signal is asserted, and it asserts the STROBE signal whenever a byte is read in or written out the parallel port. By switching pins 1 and 10, the Amiga looks like a printer to the outside world. You must send a CMD_READ to the parallel.device before the sender sends out its first byte, otherwise the transfer will lock up. If you do not wish to bother with the parallel.device, you may download data from the sender by issuing "type from par: [to filename]" at the cli prompt. Unfortunately the type command will not know when the transfer is complete, so it will never terminate. Be careful no to set your Amiga and the sender to read simoultaneously, nor to write simoultaneously. Doing so will result in blowing an 8520 in your Amiga. "And they said you could blow damage your hardware through software..." Valentin -- The Goddess of democracy? "The tyrants Name: Valentin Pepelea may distroy a statue, but they cannot Phone: (215) 431-9327 kill a god." UseNet: cbmvax!valentin@uunet.uu.net - Ancient Chinese Proverb Claimer: I not Commodore spokesman be