PMBus Addressing
307
SNIU028A – February 2016 – Revised April 2016
Copyright © 2016, Texas Instruments Incorporated
ADC12 Overview
8.13 PMBus Addressing
UCD3138 offers two constant current sources for excitation of resistors used for setting the PMBus
address, as shown in
. The two current sources are connected to CH-0 and CH-1 of ADC-12
and are disabled as default. The nominal current is preset to 10 µA.
To activate these current sources the following bits in PMBCTRL3 register in
PMBUS registers section
need to be set.
PMBusRegs.PMBCTRL3.bit.IBIAS_A_ENA = 1;
PMBusRegs.PMBCTRL3.bit.IBIAS_B_ENA = 1;
8.13.1 PMBus Control Register 3 (PMBCTRL3)
Address FFF7F620
Figure 8-12. PMBus Control Register 3 (PMBCTRL3)
20
19
18
17
16
15
CLK_LO_DIS
IBIAS_B_EN
IBIAS_A_EN
SCL_DIR
SCL_VALUE
SCL_MODE
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 8-2. PMBus Control Register 3 (PMBCTRL3) Register Field Descriptions
Bit
Field
Type
Reset
Description
20
CLK_LO_DIS
R/W
0
19
IBIAS_B_EN
R/W
0
PMBus Current Source B Control
0 = Disables Current Source for PMBUS address detection thru ADC (Default)
1 = Enables Current Source for PMBUS address detection thru ADC
18
IBIAS_A_EN
R/W
0
PMBus Current Source A Control
0 = Disables Current Source for PMBUS address detection thru ADC (Default)
1 = Enables Current Source for PMBUS address detection thru ADC
17
SCL_DIR
R/W
0
16
SCL_VALUE
R/W
0
15
SCL_MODE
R/W
0