Specifications

PCIe/104 and PCI/104-Express Specification Revision 3.0 February 17, 2015 Page 5
2.4.2
 PEG_ENA# Signal ................................................................................................................. 15
2.4.3 DIR Signal ............................................................................................................................. 15
2.4.4 Stack-UP or Stack-DOWN Link Shifting .............................................................................. 17
2.4.5 Link Shifting PCB Examples ................................................................................................. 18
2.4.6 Link Shifting Stack Examples ................................................................................................ 19
2.5. Switching ................................................................................................................................................. 21
2.5.1 Signal Switch ......................................................................................................................... 21
2.6. System Clocking ...................................................................................................................................... 21
2.7. Layout Recommendations ....................................................................................................................... 22
2.7.1 Stitching Capacitors ............................................................................................................... 22
2.7.2 Number of PCI Express Boards in the Stack ......................................................................... 22
2.8. Routing Topology .................................................................................................................................... 23
2.8.1 PCI Express and USB 3.0 ...................................................................................................... 23
2.8.2 SATA ..................................................................................................................................... 24
2.9. Device Connector Break-out Examples ................................................................................................... 25
2.9.1 Universal PCI Express x1 Device Layout Example ............................................................... 25
2.9.2 Universal PCI Express x4 Device Layout Example ............................................................... 25
2.9.3 Type 1 PCI Express x8 Device Layout Example ................................................................... 26
2.9.4 Type 1 PCI Express x16 Device Layout Example ................................................................. 26
2.9.5 Type 2 USB 3.0 Device Layout Example .............................................................................. 27
2.9.6 Type 2 SATA Device Layout Example ................................................................................. 27
3. EXPANSION CONNECTOR B ............................................................................................................................ 28
3.1. Description ............................................................................................................................................... 28
3.2. Functions.................................................................................................................................................. 28
3.3. Signal Descriptions .................................................................................................................................. 29
3.4. Pin Assignment ........................................................................................................................................ 30
3.5. +5V_SB, PSON#, and PME# .................................................................................................................. 30
3.6. PCI Signaling Voltage (VI/O) Requirements .......................................................................................... 31
3.6.1 PCI Host Module ................................................................................................................... 31
3.6.2 Add-In Modules ..................................................................................................................... 31
4. PCIe/104 Type 1 and Type 2 Stacking .................................................................................................................. 32
4.1. System Stacking Rules ............................................................................................................................. 32
4.2. Host Configuration Rules ........................................................................................................................ 32
4.3. Peripheral Configuration Rules ................................................................................................................ 33
4.4. Stack Configuration Examples ................................................................................................................ 34