6.5 Programming

The CDCDB2000 has two methods to program the states of its 20 output drivers: SMBus and SBI.

To select between SMBus and SBI interfaces, the SBEN pin is used. Pulling the SBEN to a high level enables

the SBI. Pulling the SBEN pin to ground enables the SMBus interface. When SBI is enabled, the SMBus Mask

registers are active. The SMBus Mask registers allow the function of the SBI shift registers to be disabled and

set the each individual channel as enabled. See Figure 6-2 for a diagram of how the SMBus Mask registers and

SBI shift register interact to enable or disable each output.

D

Q

Q

>

D

Q

Q

>

Q0

Q1

To Q2

OE1

OE0

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

D

Q

Q

>

OE19

From Q18

Shift

Register

Output

Register

(Default is 1)

DATA

CLK

SHFT_LD#

Mask0

Mask1

Mask19

To Output Logic

From SMBus Mask

Registers

Side-Band Interface

Figure 6-2. SMBus Mask Register and SBI Shift Register Logic

6.5.1 SMBus

SMBus programming is described in Section 6.3.2, and the registers are described in Section 7.

CDCDB2000

SNAS787B – NOVEMBER 2019 – REVISED OCTOBER 2024

www.ti.com

14

Submit Document Feedback

Copyright © 2024 Texas Instruments Incorporated

Product Folder Links: CDCDB2000