Other Data Fields

In this section

This section describes some other data fields from the example in Example of Real I2C NIM Data, which are both static and dynamic.

Temperature

The temperature field is an example of a dynamic field, which is constantly updated by the module firmware. This field is located at address 0xA02F as a 16-bit signed integer. The unit is 1/256 °C.

The bytes in the example are 0x19 and 0x37, and since the format is little endian, the least significant byte is found at the lowest address. So the two bytes represent the value 0x3719 (14105 in decimal notation). In decimal notation, the temperature is therefore 1/256 × 14105 °C = 55.098 °C. Thus the first of the two bytes represents the fraction part of the value, and the second byte represents the integer part.

Bias current

Measured laser bias current for up to 16 lanes is located at address 0xA2A0 as a 16-bit unsigned integer for each lane. The unit is 2 μA.

The bytes in the example are 0x24, 0x7B, 0xCD, 0x77, 0xC1, 0x78, 0xB5 and 0x79 for 4 lanes. The bytes for the first lane represent the value 0x7B24 (31524 in decimal notation). In decimal notation, the bias current for the first lane is therefore 2 × 31524 μA = 63.048 mA.

TX output power

Measured TX output power for up to 16 lanes is located at address 0xA2B0 as a 16-bit unsigned integer for each lane. The unit is 0.1 μW.

The bytes in the example are 0xF2, 0x4D, 0x81, 0x38, 0x1B, 0x4A, 0x46 and 0x49 for 4 lanes. The bytes for the first lane represent the value 0x4DF2 (19954 in decimal notation). In decimal notation, the TX output power for the first lane is therefore 0.1 × 19954 μW = 1.9954 mW.

RX input power

Measured RX input power for up to 16 lanes is located at address 0xA2D0 as a 16-bit unsigned integer for each lane. The unit is 0.1 μW.

The bytes in the example are 0xB4, 0x36, 0xB0, 0x2E, 0x12, 0x36, 0xBE and 0x41 for 4 lanes. The bytes for the first lane represent the value 0x36B4 (14004 in decimal notation). In decimal notation, the RX input power for the first lane is therefore 0.1 × 14004 μW = 1.4004 mW.