Communication; Physical Link Layer Protocol; I2C Signal - Huawei PAC2000S12-B1 PSU Technical Manual

PAC2000S12-B1 PSU

10.1 Physical Link Layer Protocol

10.1.1 I2C Signal

The PSU includes a main control unit (MCU) used for monitoring, and a 256-byte internal EEPROM
used for storing fault records. The PSU can use the internal EEPROM in the MCU to store fault
records. The system sends commands to the MCU over the I2C bus to read fault records from the
PSU.
Figure 10-1 shows the I2C interface communication diagram.
Figure 10-1 I2C interface
SCL and SDA are the serial clock signal and serial data signal of I2C respectively.
PSU Side
● SCL and SDA are pulled up to 3.3 V level by
a 20-kilohm resistor.
● The MCU is powered by the auxiliary power
supply of the PSU or the busbar at the
system side.
● When power is supplied from the system
side, there should be a fuse or an
overcurrent/short-circuit protection circuit.
● Capacitors on the SCL and SDA circuit are no
more than 66 pF.
Technical Manual
10

Communication

System Side
SCL and SDA are pulled up to 3.3 V level by a
3-kilohm to 10-kilohm equivalent resistor.
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10 Communication