CS5535-UDCF AMD (ADVANCED MICRO DEVICES), CS5535-UDCF Datasheet - Page 131

• Manufacturer Part Number: CS5535-UDCF
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of CS5535-UDCF

• Operating Temperature (min): 0C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Compliant

System Management Bus Controller
5.11.1.3 Acknowledge After Every Byte Rule
According to this rule, the master generates an acknowl-
edge clock pulse after each byte transfer, and the receiver
sends an acknowledge signal after every byte received.
There are two exceptions to this rule:
• When the master is the receiver, it must indicate to the
• When the receiver is full, otherwise occupied, or a
5.11.1.4 Addressing Transfer Formats
Each device on the bus has a unique address. Before any
data is transmitted, the master transmits the address of the
slave being addressed. The slave device should send an
acknowledge signal on the SDA line, once it recognizes its
address.
AMD Geode™ CS5535 Companion Device Data Book
transmitter the end of data by not acknowledging (nega-
tive acknowledge) the last byte clocked out of the slave.
This negative acknowledge still includes the acknowl-
edge clock pulse (generated by the master), but the
SDA line is not pulled down.
problem has occurred, it sends a negative acknowledge
to indicate that it cannot accept additional data bytes.
SDA
SCL
Condition
START
S
Address R/W ACK
Figure 5-28. SMB Complete Data Transaction
1 - 7
8
9
1 - 7
Data
The address consists of the first seven bits after a START
condition. The direction of the data transfer (R/W) depends
on the bit sent after the address, the eighth bit. A low-to-
high transition during an SCL high period indicates the
STOP condition, and ends the transaction of SDA (see Fig-
ure 5-28).
When the address is sent, each device in the system com-
pares this address with its own. If there is a match, the
device considers itself addressed and sends an acknowl-
edge signal. Depending on the state of the R/W bit (1 =
Read, 0 = Write), the device acts either as a transmitter or
a receiver.
The SMB protocol allows a general call address to be sent
to all slaves connected to the bus. The first byte sent spec-
ifies the general call address (00h) and the second byte
specifies the meaning of the general call (for example,
write slave address by software only). Those slaves that
require data acknowledge the call, and become slave
receivers; other slaves ignore the call.
8
ACK
9
1 - 7
Data
8
ACK
9
31506B
STOP
Condition
P
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