XFP requires reset each time otherwise TIMEOUT error

[ArT]

Some XFP transceivers allow only for single I2C communication and after i2c bus is idle for a while they turn off I2C transmission or goes to sleep. When you try to read transceiver on a first attemtp - it's ok. But when you try to read second time - you have TIMEOUT error (device is not responding). After resetting transceiver (or disconnect and connect power supply) you can read it again. In this short tutorial I'll show you how you can reset transceiver and automate the process.

How to manually reset XFP / QSFP / SFP transceiver:

• disconnect transceiver and connect it again OR,
• disconnect usb power supply from adapter board and connect it again OR,
• connect reset switch between RESET pin and GROUND (so you can manually reset it by pressing mono-stable switch). Press button every time you need to reset tranceiver.

How to automate XFP resetting with REVELPROG-IS and QSFP SFP XFP Adapter:

• connect XFP RESET pin to REVELPROG-IS pin 7 (see picture below):
  - XFP reset pin = P_Down/RST,
  note: QSFP will work only with manual reset. SFP does not have reset pin.

Please note: when you unlocked transceiveir with manufacturer or user password and you resetted the transceiver you will need to enter password again.