The S900 has what looks like a PCIe x1 slot. However this is actually a proprietary connector that they use to provide PCIe x2 functionality. The pinouts are shown below. You don't have to look past pin A3 to see that a standard card will never work.
| Pin | Standard | S900 | |
|---|---|---|---|
| A1 | PRSNT#1 | Hot plug detect | +12V |
| A2 | +12V | +12V power | +12V |
| A3 | +12V | +12V power | GND |
| A4 | GND | Ground | GND |
| A5 | JTAG2 | TCK | Rx Data (1)- |
| A6 | JTAG3 | TDI | Rx Data (1)+ |
| A7 | JTAG4 | TDO | GND |
| A8 | JTAG5 | TMS | GND |
| A9 | +3.3V | +3.3V power | Tx Data (1)- |
| A10 | +3.3V | +3.3V power | Tx Data (1)+ |
| A11 | PWRGD | Power Good | GND |
| A12 | GND | Ground | GND |
| A13 | REFCLK+ | Reference Clock | Clock+ |
| A14 | REFCLK- | Reference Clock | Clock- |
| A15 | GND | Ground | GND |
| A16 | HSI+(0) | Receiver Lane 0 | Rx DAta (0)+ |
| A17 | HSI-(0) | Receiver Lane 0 | Rx Data (0)- |
| A18 | GND | Ground | GND |
| Pin | Standard | S900 | |
| B1 | +12V | +12V power | +12V |
| B2 | +12V | +12V power | +12V |
| B3 | +12V | +12V power | +12V |
| B4 | GND | Ground | GND |
| B5 | SMCLK | SMBus clock | nc |
| B6 | SMDAT | SMBus data | nc |
| B7 | GND | Ground | GND |
| B8 | +3.3V | +3.3V power | nc |
| B9 | JTAG1 | +TRST# | nc |
| B10 | 3.3Vaux | 3.3V power | nc |
| B11 | WAKE# | Link Reactivation | WAKE low |
| B12 | RSVD | Reserved | Reset low |
| B13 | GND | Ground | GND |
| B14 | HSO+(0)- | Tx Lane 0 | Tx+ (0) |
| B15 | HSO+(0) | Tx Lane 0 | Tx- (0) |
| B16 | GND | Ground | GND |
| B17 | PRSNT#2 | Hotplug detect | nc |
| B18 | GND | Ground | GND |
[Back]