Post by thread:PCI bus voltage?

Hi all, I am working on a project with multiple PICs doing various things. They end up reporting to a board that is installed in a PC on the PCI bus (for other reasons). Does anyone know the voltage levels on the expansion PCI slots in a PC? My impression is that it is 5V, unlike the North-side PCI bus (next to the processor) which is 3.3V. Any help or pointers is appreciated. Mark A. Corio Rochester MicroSystems, Inc. 200 Buell Road, Suite 9 Rochester, NY 14624 Tel: 716-328-5850 Fax: 716-328-1144 http://www.frontiernet.net/~rmi/ ****** Designing Electronics for Research and Industry ******

On Mon, 22 Jun 1998, Mark A. Corio wrote: > Hi all, > I am working on a project with multiple PICs doing various things. They end up > reporting to a board that is installed in a PC on the PCI bus (for other > reasons). Does anyone know the voltage levels on the expansion PCI slots in a > PC? My impression is that it is 5V, unlike the North-side PCI bus (next to the > processor) which is 3.3V. Any help or pointers is appreciated. Hi Mark, I had to design a PCI bridge a couple of years ago, so I'm a little rusty, but the PCI connector tells all. In the slot there are plastic keys, and the PCI cards themselves have slotted cutouts to prevent them from being inserted in a slot with the wrong voltage. The card I designed was meant for 5 volts only, so I didn't have to deal with dual-voltage busses at that part of the circuit. look at a couple of PCI cards and the connectors in a computer and you'll see what I mean. Sorry I can't be of more help, it's been a while, perhaps others are more fresh on the subject. Cheers, bob