CS5535 datasheet(542/555 Pages) NSC

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542

Revision 0.8

Electrical Specifications (Continued)

6.3.7

System Management Bus (SMB) Signals

The signals detailed in this sub-section use an “SMB”

buffer type. For a detailed explanation of buffer types, see

Table 2-4 "Buffer Type Characteristics" on page 28.

The SMB utilizes a two-wire asynchronous protocol. Mas-

ter and slave devices are connected open-drain with an

external pull-up resistor. The SMB_CLK is not a free run-

ning fixed frequency signal, but rather a cooperatively gen-

erated signal with a minimum low time of 4.7 µs, minimum

high time of 4.0 µs, and 100 kHz frequency limit. The mini-

mum frequency is 10 kHz. The SMB_DATA signal is also

cooperatively driven. Communication on the SMB is via rel-

ative manipulation of these two signals. The SMB Control-

ler and I/O cell incorporated within the CS5535 fully meets

the requirements of the SMB specification version 2.0.

In this subsection, unless otherwise noted:

• All timing specifications are specified under the oper-

ating conditions listed in Table 6-3 on page 526 (i.e.,

VCORE and VCORE_VSB = All; VIO and VIO_VSB = All;

TCASE = All).

Table 6-15. SMB Timing Parameters

Signal

Parameter

Min

Max

Units

Comment/Condition

Bidirectional

SMB_CLK (GPIO14),

SMB_DATA (GPIO15)

Async Output or Level

No clock reference.

Async Input

No clock reference.

CS5535 Datasheet(PDF) 542 Page - National Semiconductor (TI)