Why I2C require in PCIe interface?

[kpec1988]

Hi
Anyone know why I2C interface is required in PCIe interface?

 

[kirill]

"In addition to the boundary-scan test features, the PCIe-1149.1 also includes direct I2C and serial peripheral interface (SPI) based device programming capabilities. The SPI and I2C interfaces are independent of the JTAG test interface, meaning the same boundary-scan controller tests the board and performs direct programming of serial EEPROM and flash memories, without operators having to remove the JTAG connector or switch to a dedicated SPI or I2C programmer."

 

[kpec1988]

"In addition to the boundary-scan test features, the PCIe-1149.1 also includes direct I2C and serial peripheral interface (SPI) based device programming capabilities. The SPI and I2C interfaces are independent of the JTAG test interface, meaning the same boundary-scan controller tests the board and performs direct programming of serial EEPROM and flash memories, without operators having to remove the JTAG connector or switch to a dedicated SPI or I2C programmer."

Hi kirill
Thanks for your support can you tell me this feature is available in PCI interface?

 

[kirill]

such interfaces like i2c, spi is the common features for debug, programming in different complex modules(integrated circuits, may be ip cores). PCI interface is a part of protocol, which could implement on different hardware. So it is depend on your hardware, will it have i2c spi interfaces for debug or programming or not.
Hope i understand your question correctly.

 

[kpec1988]

Thanks kirill
I understand very well.Before this thread I dont have any knowledge about PCIe 1149.1. I read some document on it so I get better knowledge of PCIe 1149.1

 

[kirill]

it was only example. first link from google) i tried to explain for what i2c interface could need for. but i think additional knowledge never be unnecessary) sorry for my english.

 

[FvM]

The purpose of the I2C (respectively SMB) interface for PCIe is explained in the PCI Express Card Electromechanical Specification:

The optional System Management Bus (SMBus) is a two-wire interface through which various system component chips can communicate with each other and with the rest of the system. It is based on the principles of operation of I2C.

SMBus provides a control bus for system and power management related tasks. A system may use SMBus to pass messages to and from devices instead of tripping individual control lines. Removing the individual control lines reduces pin count. Accepting messages ensures future expandability.

With SMBus, a device can provide manufacturer information, tell the system what its model/part number is, save its state for a suspend event, report different types of errors, accept control parameters, and return its status.

As the specification clearly states, the implementation of SMB/I2C is optional. Beyond testing purposes, as addressed in 1149.1, it's also intended for regular device operation.