RE: PC 104 plus signals

[Hartley Sweeten <hsweeten@mobl.com>]

The PC104+ specification allows for up to four cards in the stack. The CLKx, GNTx, REQx and IDSELx [x=0-3] go to the appropriate card in the stack. Typically a rotary switch is used with a couple of dual 4:1 mux/demux chip such as QuickSwitch QS3253 to allow the for the selection. On a standard PCI system with slots this is handled by the routing to the connectors. Since the connector is shared in the PC104+ format the selection has to be done in another manner.

 

Look at the specification under 2.2 Signal Grouping for more information.

 

Hartley Sweeten

Mobility Electronics

-----Original Message-----
From: Ola Wiberg [mailto:ola_wiberg@viscount.com]
Sent: Tuesday, July 23, 2002 8:30 AM
To: Mail List PCI-SIG (E-mail)
Subject: PC 104 plus signals

Hi,

 

I am working on a board using the PCI bus in a PC104 plus format. There are some signals on that bus that are multiplied compared with the standard PCI.  My question is how do I deal with them. Whay are there more than one Clk for instance, are these different in any way?

 

The signals I am talking about are.

 

CLK0,1,2,3

GNT1,2,3

IDSEL0,1,2,3

 

Thanks in advance,

 

Ola

 

* * * * * * * * * * * * * * * * * * * * * * * * *
Ola Wiberg

mailto:ola_wiberg@viscount.com
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