W312-02_05 Datasheet, PDF (5/20 Pages) Cypress Semiconductor – FTG for VIA™ K7 Series Chipset with Programmable Output Frequency

Table 3. Word Read and Word Write Protocol
Word Write Protocol
Bit
Description
1
Start
2:8 Slave address – 7 bits (D2)
9
Write
10
Acknowledge from slave
11:18
Command Code – 8 bits
‘1xxxxxxx’ stands for byte or word operation
bit[6:0] of the command code represents the
offset of the byte to be accessed
19
Acknowledge from slave
20:27 Data byte low – 8 bits
28
Acknowledge from slave
29:36 Data byte high – 8 bits
37
Acknowledge from slave
38
Stop
Table 4. Byte Read and Byte Write Protocol
Byte Write Protocol
Bit
Description
1
Start
2:8 Slave address – 7 bits
9
Write
10
Acknowledge from slave
11:18
Command Code – 8 bits
‘1xxxxxxx’ stands for byte operation
bit[6:0] of the command code represents the
offset of the byte to be accessed
19
Acknowledge from slave
20:27 Data byte – 8 bits
28
Acknowledge from slave
29
Stop
W312-02
Bit
1
2:8
9
10
11:18
19
20
21:27
28
29
30:37
38
39:46
47
48
Word Read Protocol
Description
Start
Slave address – 7 bits (D3)
Write
Acknowledge from slave
Command Code – 8 bits
‘1xxxxxxx’ stands for byte or word operation
bit[6:0] of the command code represents the
offset of the byte to be accessed
Acknowledge from slave
Repeat start
Slave address – 7 bits
Read
Acknowledge from slave
Data byte low from slave – 8 bits
Acknowledge
Data byte high from slave – 8 bits
NOT acknowledge
Stop
Bit
1
2:8
9
10
11:18
19
20
21:27
28
29
30:37
38
39
Byte Read Protocol
Description
Start
Slave address – 7 bits
Write
Acknowledge from slave
Command Code – 8 bits
‘1xxxxxxx’ stands for byte operation
bit[6:0] of the command code represents the
offset of the byte to be accessed
Acknowledge from slave
Repeat start
Slave address – 7 bits
Read
Acknowledge from slave
Data byte from slave – 8 bits
Not Acknowledge
Stop
Document #: 38-07259 Rev. *C
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