The Secure Device Manager (SDM) in the Intel® Stratix® 10 FPGA cannot be used to read data from, or write commands to, a Voltage Regulator Module (VRM) or any other agent on the Power Management Bus (PMBus).
As a PMBus host, the Intel® Stratix® 10 FPGA PMBus interface is designed only to provide the communications across the PMBus required for the SmartVID logic to control the Voltage Regulator Module (VRM) that is supplying power to VCC/VCCP. Other logic in the device cannot access the PMBus control logic, so the user cannot take control of the Intel® Stratix® 10 PMBus logic.
The Intel® Stratix® 10 FPGA PMBus interface can also be operated as a PMBus agent, using the PMBus Alert signal to signal the PMBus host when the SmartVID logic changes the VRM voltage. In this mode, the external PMBus host can use normal PMBus commands to read and control the VRM directly. This is useful when performing voltage margining of VCC during board tests or when implementing board-level power management.