Slot Image
PCI Express, also known as PCI-E and officially abbreviated as PCIe, is an important computer bus standard. The slot is shown below:
Pinout
The table below lists the contacts on both sides of a PCI Express card edge connector. Side A is the solder side of the printed circuit board (PCB), and side B is the component side. The PRSNT1# and PRSNT2# pins are shorter than the other pins so the system can detect that a hot-plug card is fully inserted. WAKE# is used to wake the computer and must be pulled up from the auxiliary power rail to indicate that the card supports wake.
| Pin | Side B | Side A | Description | Pin | Side B | Side A | Description | |
|---|---|---|---|---|---|---|---|---|
| 1 | +12 V | PRSNT1# | Must connect to the farthest PRSNT2# pin | 50 | HSOp (8) | Reserved | Lane 8 transmit data, + and - | |
| 2 | +12 V | +12 V | 51 | HSOn (8) | Ground | |||
| 3 | +12 V | +12 V | 52 | Ground | HSIp (8) | Lane 8 receive data, + and - | ||
| 4 | Ground | Ground | 53 | Ground | HSIn (8) | |||
| 5 | SMCLK | TCK | SMBus and JTAG port pins | 54 | HSOp (9) | Ground | Lane 9 transmit data, + and - | |
| 6 | SMDAT | TDI | 55 | HSOn (9) | Ground | |||
| 7 | Ground | TDO | 56 | Ground | HSIp (9) | Lane 9 receive data, + and - | ||
| 8 | +3.3 V | TMS | 57 | Ground | HSIn (9) | |||
| 9 | TRST# | +3.3 V | 58 | HSOp (10) | Ground | Lane 10 transmit data, + and - | ||
| 10 | +3.3 V aux | +3.3 V | Auxiliary power | 59 | HSOn (10) | Ground | ||
| 11 | WAKE# | PERST# | Link activation; fundamental reset | 60 | Ground | HSIp (10) | Lane 10 receive data, + and - | |
| Key notch | 61 | Ground | HSIn (10) | |||||
| 12 | CLKREQ# | Ground | Clock request | 62 | HSOp (11) | Ground | Lane 11 transmit data, + and - | |
| 13 | Ground | REFCLK+ | Reference clock differential pair | 63 | HSOn (11) | Ground | ||
| 14 | HSOp (0) | REFCLK− | 64 | Ground | HSIp (11) | Lane 11 receive data, + and - | ||
| 15 | HSOn (0) | Ground | 65 | Ground | HSIn (11) | |||
| 16 | Ground | HSIp (0) | Lane 0 receive data, + and - | 66 | HSOp (12) | Ground | Lane 12 transmit data, + and - | |
| 17 | PRSNT2# | HSIn (0) | 67 | HSOn (12) | Ground | |||
| 18 | Ground | Ground | 68 | Ground | HSIp (12) | Lane 12 receive data, + and - | ||
| PCI Express x1 cards end at pin 18 | 69 | Ground | HSIn (12) | |||||
| 19 | HSOp (1) | Reserved | Lane 1 transmit data, + and - | 70 | HSOp (13) | Ground | Lane 13 transmit data, + and - | |
| 20 | HSOn (1) | Ground | 71 | HSOn (13) | Ground | |||
| 21 | Ground | HSIp (1) | Lane 1 receive data, + and - | 72 | Ground | HSIp (13) | Lane 13 receive data, + and - | |
| 22 | Ground | HSIn (1) | 73 | Ground | HSIn (13) | |||
| 23 | HSOp (2) | Ground | Lane 2 transmit data, + and - | 74 | HSOp (14) | Ground | Lane 14 transmit data, + and - | |
| 24 | HSOn (2) | Ground | 75 | HSOn (14) | Ground | |||
| 25 | Ground | HSIp (2) | Lane 2 receive data, + and - | 76 | Ground | HSIp (14) | Lane 14 receive data, + and - | |
| 26 | Ground | HSIn (2) | 77 | Ground | HSIn (14) | |||
| 27 | HSOp (3) | Ground | Lane 3 transmit data, + and - | 78 | HSOp (15) | Ground | Lane 15 transmit data, + and - | |
| 28 | HSOn (3) | Ground | 79 | HSOn (15) | Ground | |||
| 29 | Ground | HSIp (3) | Lane 3 receive data, + and - | 80 | Ground | HSIp (15) | Lane 15 receive data, + and - | |
| 30 | Reserved | HSIn (3) | 81 | PRSNT2# | HSIn (15) | |||
| 31 | PRSNT2# | Ground | 82 | Reserved | Ground | |||
| 32 | Ground | Reserved | ||||||
| PCI Express x4 cards end at pin 32 | ||||||||
| 33 | HSOp (4) | Reserved | Lane 4 transmit data, + and - | |||||
| 34 | HSOn (4) | Ground | ||||||
| 35 | Ground | HSIp (4) | Lane 4 receive data, + and - | |||||
| 36 | Ground | HSIn (4) | ||||||
| 37 | HSOp (5) | Ground | Lane 5 transmit data, + and - | |||||
| 38 | HSOn (5) | Ground | ||||||
| 39 | Ground | HSIp (5) | Lane 5 receive data, + and - | |||||
| 40 | Ground | HSIn (5) | ||||||
| 41 | HSOp (6) | Ground | Lane 6 transmit data, + and - | |||||
| 42 | HSOn (6) | Ground | ||||||
| 43 | Ground | HSIp (6) | Lane 6 receive data, + and - | Legend | ||||
| 44 | Ground | HSIn (6) | Ground pins | Zero-voltage reference | ||||
| 45 | HSOp (7) | Ground | Lane 7 transmit data, + and - | Power pins | Power supplied to the PCIe card | |||
| 46 | HSOn (7) | Ground | Output pins | Signals from the PCIe card to the motherboard | ||||
| 47 | Ground | HSIp (7) | Lane 7 receive data, + and - | Input pins | Signals from the motherboard to the PCIe card | |||
| 48 | PRSNT2# | HSIn (7) | Open drain | Can be pulled low or used to detect multiple cards | ||||
| 49 | Ground | Ground | Presence-detect pins | Card presence connection | ||||
| PCI Express x8 cards end at pin 49 | Reserved | Currently unused; do not connect | ||||||