Specifications
PCIe/104 and PCI/104-Express Specification Revision 3.0 February 17, 2015 Page 30
3.4. Pin Assignment
Signals are assigned in the same relative order as in the PCI Local Bus Specification Revision 2.2, but transformed to the
corresponding header connector pins. Because of the stack-through nature of the bus, slot-specific signals are duplicated
for each plug-in module. The system has been designed to accommodate 4 modules, which are PC/104-Plus, PCI-104, or
a combination of the two, so multiple sets of the signals have been duplicated to accommodate one signal for each
module. These four signal groups include: IDSEL[3:0], CLK[3:0], REQ#[3:0], GNT#[3:0]. Signal assignments for the
J3/P3 connector are given in Table 3-2.
Table 3-2 Connector Signal Assignment
3.5. +5V_SB, PSON#, and PME#
To support ATX power supplies and power down features three signals have been added to the PCI bus. They are
+5V_SB which is a power source that is always present when main power is supplied to the system, PSON# which is a
power supple control signal that can turn the power supple on or off, and PME# which can be used to bring the CPU out
of power down states such as wake-on-LAN.
These signals have been implemented on the reserved pins of the PCI expansion bus of the PC/104-Plus and PCI-104
Specifications at pins B1, C9, and D10. Not all manufacturers will implement these signals; therefore to maintain
compatibility with existing products it is important for designs that implement these functions to protect against undriven
inputs.
A B C D
1 GND +5V_SB +5V AD00
2 VI/O AD02 AD01 +5V
3 AD05 GND AD04 AD03
4 C/BE0# AD07 GND AD06
5 GND AD09 AD08 GND
6 AD11 VI/O AD10 M66EN
7 AD14 AD13 GND AD12
8 +3.3V C/BE1# AD15 +3.3V
9 SERR# GND PSON# PAR
10 GND PERR# +3.3V PME#
11 STOP# +3.3V LOCK# GND
12 +3.3V TRDY# GND DEVSEL#
13 FRAME# GND IRDY# +3.3V
14 GND AD16 +3.3V C/BE2#
15 AD18 +3.3V AD17 GND
16 AD21 AD20 GND AD19
17 +3.3V AD23 AD22 +3.3V
18 IDSEL0 GND IDSEL1 IDSEL2
19 AD24 C/BE3# VI/O IDSEL3
20 GND AD26 AD25 GND
21 AD29 +5V AD28 AD27
22 +5V AD30 GND AD31
23 REQ0# GND REQ1# VI/O
24 GND REQ2# +5V GNT0#
25 GNT1# VI/O GNT2# GND
26 +5V CLK0 GND CLK1
27 CLK2 +5V CLK3 GND
28 GND INTD# +5V RST#
29 +12V INTA# INTB# INTC#
30 -12V REQ3# GNT3# GND