KCU1250 User Guide
45
UG1057 (v1.0) December 19, 2014
Chapter 1:
KCU1250 Board Features and Operation
I2C Bus Management
The I2C bus is routed through U22, an 8-channel I2C-bus multiplexer (NXP Semiconductor
TCA9548). The I2C IDcode for the TCA9548 device is 0x75. The multiplexer provides
I2C/PMBus communication between the bus master (system controller or FPGA) and six
sub-systems:
• Onboard regulators and power monitoring
• SuperClock-2 module
• MGT power module
• FMC1
• FMC2
• FMC3
shows the I2C channel assignments.
The upstream port of the TCA9548 multiplexer connects to PCA9306 (U46, U53, U55, and
U58) dual bidirectional I2C and SMBus voltage-level translator and bus repeaters, with an
enable (EN) signal (see
). J121 and J125 are used to enable or disable the bus
repeaters and isolate the system controller or the UltraScale FPGA I2C bus.
Table 1-20:
I2C Channel Assignments
U22 Channel
I2C Component
0
System PMBus
1
SuperClock-2 module
2
MGT power module
3
FMC1
4
FMC2
5
FMC3