On Thu 13 Nov, wrote: > > Hello Friends > > Does someone know some software that identify if PC parallel Port is > bidirectional or not? And > configure it? > > Miguel. There's several different ways to determine whether your PC's parallel port is bidirectional: 1. If it's on a ISA plug in card, and the card is less than 3 years old then it probably has bidirectional, EPP and ECP 2. Same for parallel ports on PC motherboards less than 4 years old. 4. If it uses an SMC 37C66x I/O controller then it's bidir/EPP/ECP capable 8. You can also run Windoze and check in the System thingy. 16. There is also a number of parallel port testing programs (check the usual places) that run under DOS. If you intend to run your PIC stuff for more than just a few days, then you should implement full IEEE1284 negotiation. This allows the PC to determine what's connected to the parallel port (reading an ID string in nibble mode), and also this handshaking makes sure that you don't accidentally drive the parallel port from the PIC as well as from the host PC. Implementing the IEEE1284 negotiation is a bore, but once you've done that you can keep the code in your library. As for protocol, I'd recommend using ECP mode for most uses. It has much more relaxed timings than EPP at the same data rate (up to 2MB/s) and uses fewer signals in the actual data transfer. In our application, we have the PIC do all the negotiation stuff, and then have the PIC hand over control to an FPGA which will then blast data over the port as fast as the host allows. You'll have to get the datasheet for the I/O chip on your PC. QuestLink should be able to give you PDF datasheets. http://standards.ieee.org/ will sell you a copy of the relevant standard, IEEE Std 1284-1994, ISBN 1-55937-427-6 for $50-100 or so. Frank ------------------------------------------------------------------------ Frank A. Vorstenbosch Phone: +44-181-636 3391 Electronics & Software Engineer or: +44-181-636 3000 Eidos Technologies Ltd., Wimbledon, London Mobile: +44-976-430 569