Request for SmartVID PMBus Compatibility Requirements for Replacing VRM on Agilex 7

Hello, 

Agilex SDM SmartVID uses a small PMBus command set, centered on VOUT_COMMAND (0x21), READ_VOUT (0x8B), optional VOUT_MODE (0x20), and optional PAGE (0x00) when the rail is page-based.

1- PMBUS addressing - The replacement must support 7-bit PMBus addressing; internal guidance explicitly says PMF uses 7-bit, not 10-bit, addressing.

The address used on board must match the address configured in Quartus.

2- Supported bus speed - The VR must support 100 kHz and 400 kHz PMBus bus speeds.

Quartus exposes bus-speed configuration; one internal example shows 100 kHz being set explicitly.

3- No required vendor -The preferred requirement is that the VR must operate without vendor-specific commands, including no unlock command and no special access sequence.

4- Voltage programming command compatibility -The VR must support VOUT_COMMAND at command code 0x21, 2-byte write, to set target voltage.

5. Voltage readback compatibility - The VR must support READ_VOUT at command code 0x8B, 2-byte read.

SDM/PMF polls it rapidly after programming voltage until target is reached.

6- Readback cadence /ADC behavior- The VR must tolerate multiple back-to-back READ_VOUT commands during initialization.

Internal guidance also says ADC sampling should be faster than 10 ms without special commands, otherwise init may take too long and fail.

7- output format-The VR must operate in either LINEAR or DIRECT PMBus format.

VOUT_MODE (0x20) is listed as optional readback for mode discovery.

8- Fault threshold configuration- VR should have this to avoid flash from damaged.

9- Power-on behavior before PMBus control

The VR should come up on its own to a configurable power-on voltage aligned to FPGA datasheet needs; it should not require PMF to turn it on.

10- Fault threshold configuration

The VR should have configurable OV/UV thresholds to prevent out-of-spec voltage to the FPGA.

11- PMBus robustness

The VR should implement a message timeout so that if an incomplete/corrupted message is received, it flushes buffers and resets the I2C/PMBus interface cleanly. This is another non-obvious item that can matter in the field.

12- Multi-master tolerance

The VR should tolerate multi-master operation on the PMBus. 

13- Quartus settings must match the actual regulator interface

Quartus exposes and/or stores at least these SmartVID-related settings:

• slave device type
• slave addresses
• bus speed
• voltage output format
• linear exponent N
• page command enable / page payload

Summary: 

• PMBus slave address — Yes, required.

• VOUT_MODE (0x20) — Required if used for mode discovery/config consistency; command is part of expected generic set but listed optional.

• Linear exponent N — Yes, required for LINEAR mode.

• VOUT_COMMAND format/scaling — Yes, required.

• READ_VOUT response format — Yes, required.

• OPERATION behavior — Not shown in the internal required-command list 

• STATUS_WORD / STATUS_BYTE behavior — Not shown in the internal required.

• PAGE support/config — Required only if the VR uses multiple pages for Vcore control.

• PMBus bus speed — Yes, 100/400 kHz support required.

• Manufacturer-specific commands — Prefer none; generic support assumes none required.

• Other SDM-specific PMBus transactions —  the core generic transaction set is very small: VOUT_COMMAND, READ_VOUT, optional VOUT_MODE, optional PAGE.

regards,
Farabi