DS80PCI800: surpise removal issue

Hi Tommy,

Reviewed this schematic and please note comments below:

1). Please consider using DS80PCI810 for this application. DS80PCI810 has more linearity. This allows a more optimal link training result. This is especially true for applications which put the DS80PCI8xx close to a system components Tx pins. Further this device is pin compatible with DS80PCI800.

2). As you have in your schematic, it is a good idea to start with lowest EQ and DEM settings. Then you can fine tune these settings if needed. It would be a good idea to do simulation using IBIS-AMI  model of this device plus your own media s-parameters - if these are available.

3). Please note, upon power up DS80PCI800 need to read configurations from EEPROM. BMC_DAT and BMC_CLK are used to connected DS80PCI800 I2C lanes to the EEPROM. At the same time, PCA9545 is connected to the EEPROM as well. Just want to make sure there is no contention.

4). PRSNT# signal is tied to GND through 1K-ohm Resistor. It is a good idea to connect this signal to PCIe Reset(true on high) or power good signal to synchronize the device with the PCIe interface.

5). It would be a good idea to have the option of enabling SMBus slave mode or master mode. This will allow using SMBus controller to read and write into registers.

Regards,, Nasser