Version 1.0
Page 20
2.7.2
PMBUS Interface
A PMBus is used on the UltraZed-EG SOM to program/control/monitor all on-board PMBus voltage
regulators. The UltraZed-EG SOM has access to the end-user carrier card PMBus signals via the JX2
connector (
PMBUS_SDA
,
PMBUS_SCL
, and
P5_PMBUS_ALERT_N
signals).
After the initial programming of all PMBus voltage regulators, the UltraZed-EG SOM can drive the PMBus
(via channel 1 of the I2C switch/mux and P5 port of the I2C 8-bit I/O expander) in order to control/monitor
the PMBus voltage regulators on the UltraZed-EG SOM for the purpose of power management and/or
measurements. If the PMBus is implemented on the end-user carrier card, the UltraZed-EG SOM PMBus
can monitor/control the end-user carrier card PMBus voltage regulators as well.
If not used, the UltraZed-EG SOM PMBus interface must be left unconnected on the end-user carrier
cards so that the UltraZed-EG SOM can still control/monitor its on-board PMBus regulators
.
Table 17
–PMBUS JX2 Connector Mapping
PMBUS NAME
JX2 CONNECTOR
PMBUS_SDA
JX2.11
PMBUS_SCL
JX2.12
P5_PMBUS_ALERT_N
JX2.35
The following figure shows how the PMBus will be connected on the UltraZed-EG SOM and the UltraZed
IO Carrier Card from Avnet.
I2C 8-Bit I/O
Expander
I2C
– MIO[24:25]
2-Channel
I2C Switch/Mux
P5
SD1/SC1
SDA/SCL
MPSoC
PS
SDA/SCL
PMBus
Voltage
Regulator
PMBus
Header
PMBus
Voltage
Regulator
PMBus_DATA, PMBus_CLK, PMBus_ALE RT#
JX2 Connector
PMBus_ALE RT#
PMBus_DATA, PMBus_CLK
UltraZed IO Carrier Card
UltraZed-EG SOM
PMBus
Voltage
Regulator
Shunt Jumpers
JP2/JP3
0-ohm
Resistor
Figure 10
– PMBUS Connections