Specifications

PCIe/104 and PCI/104-Express Specification Revision 3.0 February 17, 2015 Page 3
1.4.2 PCI/104-Express Version 1.0 and 1.1 Peripheral Board Compatibility
All PCI Express x1, USB 2.0, and SMBus boards build to version 1.0 or 1.1 are considered Universal boards and will
work unchanged on either Type 1 or Type 2 host CPUs. PCI Express x16 peripherals work only on Type 1 hosts. USB
3.0, SATA, and LPC peripherals will work only on Type 2 hosts.
The pin assignments on Bank 1 of the connector is exactly the same in Type 1 and Type 2, therefore all the PCI Express
x1, USB 2.0, SMBus, and all the control signals are the same. Likewise all power and grounds are the same throughout
the connector.
1.5. PCIe/104 Feature Set
1.5.1 Connector A : PCI Express Bus
PCIe/104 Type 1, Type 2 and the OneBank implementation have this common feature set and pin assignments:
Four x1 PCI Express Links
Two USB 2.0
ATX power and control signals: +5V Standby, Power supply on, Power OK
Power: +3.3V, +5V, +12V (A OneBank implementation does not include +12V)
SMBus
Type 1 has the common feature set plus:
One x16 PCI Express Link, or optionally two x8 Links, or two x4 PCI Express Links
Type 2 has the common feature set plus:
Two x4 PCI Express Links
Two USB 3.0
Two SATA
LPC Bus
RTC Battery
1.6. PCI/104-Express Feature Set
1.6.1 Connector A : Same as 1.5.1 above
1.6.2 Connector B: PCI Bus:
PCI Bus: 32 bit, 33 MHz, Four Bus Master capable (same as on PC/104-Plus and & PCI-104)
+5V Standby, Power supply on, and power management event signals for ATX power supply
Power: +3.3V, +5V, +12V, -12V
Same location and pin out as PCI-104 and PC/104-Plus specifications
1.7. General Stacking Rules
This specification defines Type 1 and Type 2 host and peripheral modules. There are four stacking rules.
Peripheral modules connecting with PCI Express x1 or x4 links, USB 2.0 links, or SMB are universal and can
plug into either a Type 1 or a Type 2 host.
Peripheral modules connecting with PCI Express x16 or x8 links must plug into a Type 1 host.
Peripheral modules connecting with SATA, USB 3.0, or LPC links must plug into a Type 2 host.
Any peripheral module plugged in the wrong bus holds the system in reset and causes no damage.
Guidelines for stacking PCI Express Gen 1, 2, 3, USB 3.0, and SATA.
• Build a stack by putting higher clock rate peripherals closer to the host. Follow the priority below:
1. Gen 3 PCI Express at 8.0 Gigabits/second closest to the host
2. SATA 3 at 6.0 Gigabits/second next closest
3. Gen 2 PCI Express and USB 3.0 at 5.0 Gigabits/second
4. SATA 2 at 3.0 Gigabits/second
5. Gen 1 PCI Express at 2.5 Gigabits/second