PMBus Interface Registers Reference
390
SNIU028A – February 2016 – Revised April 2016
Copyright © 2016, Texas Instruments Incorporated
PMBus Interface/I2C Interface
10.10.7 PMBus Control Register 2 (PMBCTRL2)
PMBus Control Register 2 (PMBCTRL2)
Figure 10-59. PMBus Control Register 2 (PMBCTRL2)
30
29
23
SLAVE_ADDR_2
_EN*
SLAVE_ADDR_2*
R/W-0
R/W-110 0000
22
21
20
19
18
16
RX_BYTE_ACK_CNT
MAN_CMD
TX_PEC
TX_COUNT
R/W-11
R/W-0
R/W-0
R/W-000
15
14
8
7
6
0
PEC_
ENA
SLAVE_MASK
MAN_SLAVE_
ACK
SLAVE_ADDR
R/W-0
R/W-111 1111
R/W-0
R/W-111 1100
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 10-11. PMBus Control Register 2 (PMBCTRL2) Register Field Descriptions
Bit
Field
Type
Reset
Description
30
SLAVE_ADDR_2_
EN*
R/W
0
Enable auto detection of the 2nd slave address.
0 = 2nd slave address disabled (default)
1 = 2nd slave address enabled
*Only available on UCD3138A64 and UCD3138128 A and non-A versions
29-23
SLAVE_ADDR_2*
R/W
110 0000 Configures the second device address of the slave. Used in automatic slave address
acknowledge mode (default mode).
*Only available on UCD3138A64 and UCD3138128 A and non-A versions)
22-21
RX_BYTE_ACK
_CNT
R/W
11
Configures number of data bytes to automatically acknowledge when receiving data
in slave mode.
00 = 1 byte received by slave. Firmware is required to manually acknowledge every
received byte.
01 = 2 bytes received by slave. Hardware automatically acknowledges the first
received byte. Firmware is required to manually acknowledge after the second
received byte.
10 = 3 bytes received by slave. Hardware automatically acknowledges the first 2
received bytes. Firmware is required to manually acknowledge after the third
received byte.
11 = 4 bytes received by slave. Hardware automatically acknowledges the first 3
received bytes. Firmware is required to manually acknowledge after the fourth
received byte (Default)
20
MAN_CMD
R/W
0
Manual Command Acknowledgement Mode
0 = Slave automatically acknowledges received command code (Default)
1 = Data Request flag generated after receipt of command code, firmware required
to issue ACK to continue message
19
TX_PEC
R/W
0
Asserted when the slave needs to send a PEC byte at end of message. PMBus
Interface will transmit the calculated PEC byte after transmitting the number of data
bytes indicated by TX Byte Cnt(Bits 19:17).
0 = No PEC byte transmitted (Default)
1 = PEC byte transmitted at end of current message
18-16
TX_COUNT
R/W
000
Number of valid bytes in Transmit Data Register
0 = No bytes valid (Default)
1 = One byte valid, Byte #0 (Bits 7:0 of Receive Data Register)
2 = Two bytes valid, Bytes #0 and #1 (Bits 15:0 of Receive Data Register)
3 = Three bytes valid, Bytes #0-2 (Bits 23:0 of Receive Data Register)
4 = Four bytes valid, Bytes #0-3 (Bits 31:0 of Receive Data Register)