Nvidia BlueField-2 User Manual page 98

Pin#
15 NCSI_TX_D1
16 BMC_TX5
17 PRESENCE_N
18 GND
19 NCSI_ARB_IN
20 NCSI_ARB_OUT
Pin Name
Input
Output
Output
Ground
Input
Output
IO
Transmit Data In 0. Data signals from the BMC to the network controller.
For baseboards, this pin should be connected between the baseboard NC-SI over RBT PHY
and the connector. This signal requires a 100 kΩ pull-down resistor to GND on the
baseboard between the RBT isolator and the DPUcable connector to prevent the card-
side signals from floating when the RBT signals are isolated.
For DPUs, this pin should be connected between the connector and the RBT PHY.
External termination is determined by the DPU RBT PHY requirements.
UART transmit serial data output. 3.3V UART TX signal to the baseboard.
Presence of SmartNIC
The baseboard should implement a 200 Ω series resistor and 4.7kohm pull-up resistor to
3.3V AUX.
SmartNIC should tie this to GND.
Ground
NC-SI hardware arbitration input
If the baseboard supports multiple DPU cards connected to the same RBT interface, it
should implement logic that connects the RBT_ARB_IN pin of the first populated DPU
card to its RBT_ARB_OUT pin if it is the only card present or to the RBT_ARB_OUT pin of
the next populated card and so on sequentially for all cards on the specified RBT bus to
ensure the arbitration ring is complete. This logic should bypass slots that are not
populated or powered off.
NC-SI hardware arbitration output.
If the baseboard supports multiple DPU cards connected to the same RBT interface, it
should implement logic that connects the RBT_ARB_OUT pin of the first populated DPU
card to its RBT_ARB_IN pin if it is the only card present or to the RBT_ARB_IN pin of the
next populated card and so on sequentially for all cards on the specified RBT bus to
Description/Comments
98