cs5535 National Semiconductor Corporation, cs5535 Datasheet - Page 122

• Manufacturer Part Number: cs5535
• Description: Geode Cs5535 Companion Multi-function South Bridge
• Manufacturer: National Semiconductor Corporation

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SMB Controller Functional Description
4.10.1.8 Configuration
SDA and SCL Signals
The SDA and SCL are open-drain signals. The device per-
mits the user to define whether to enable or disable the
internal pull-up of each of these signals.
SMB Clock Frequency
The SMB permits the user to set the clock frequency for the
System Management Bus clock. The clock is set by the
SMBCTL2.SCLFRQ field and the SMBCTL3 register,
which determines the SCL clock period used by the device.
This clock low period may be extended by stall periods initi-
ated by the SMB or by another System Management Bus
device. In case of a conflict with another bus master, a
shorter clock high period may be forced by the other bus
master until the conflict is resolved.
SDA
Line
Address
Device
Figure 4-28. SMB Byte Write
(Continued)
Word Address
122
4.10.1.9 Transaction Types
Byte Write
Sequence of events (see Figure 4-28):
1)
2)
3)
4)
5)
6)
7)
8)
START
Address phase
Acknowledge
Word address
Acknowledge
Data
Acknowledge
STOP
Data
Revision 0.8