S
1
2
PMBUS_CLK
PMBUS_DATA
t
START
UNIT_BUSY
SLAVE_ADDR_READY
DATA_REQUEST(1)
Slave Address
A
7
8
R/W
t
SAR
Write to ACK
(Stretch)
t
DREQ1
DATA_REQUEST(2)
t
ACKWRITE
t
DREQ2
S
1
2
PMBUS_CLK
PMBUS_DATA
t
RPTSTRT
RPT_START
Slave Address
A
PMBus Slave Mode Low Level Timing
369
SNIU028A – February 2016 – Revised April 2016
Copyright © 2016, Texas Instruments Incorporated
PMBus Interface/I2C Interface
10.5 PMBus Slave Mode Low Level Timing
These diagrams give the low level timing for the PMBus logic. They show the timing between events on
the PMBus pins and PMBus register changes.
For each timing parameter, only one case is shown. Note that the same timing parameter may occur in
different places in a PMBus message.
Some of the timing diagrams show a clock stretch. These are optional. If the firmware can respond fast
enough, no clock stretch will be necessary.
Figure 10-17. Address Byte Timing
Note: Stretch is optional, depending on firmware timing.
Figure 10-18. Repeated Start Timing