CY28312B-2
Pin Definitions (continued)
Pin
Type
Pin Name
SDATA
Pin No.
Pin Description
Data pin for SMBus circuitry.
Clock pin for SMBus circuitry.
31
30
40
I/O
I
SCLK
VDD_CPU
P
2.5V Power Connection. Power supply for CPU output buffers. Connect to
2.5V.
VDDQ_AGP
VDDQ_PCI
VDDQ_48MHz
VDD_REF
25
P
P
P
P
3.3V Power Connection. Power supply for AGP output buffers. Connect to 3.3V.
3.3V Power Connection. Power supply for PCI output buffers. Connect to 3.3V.
3.3V Power Connection. Power supply for 48-MHz output buffers. Connect to 3.3V.
15, 23
5
1
3.3V Power Connection: Power supply for reference output buffers. Connect
to 3.3V.
VDD_Core
33
P
3.3V Power Connection: Power supply for PLL core. Connect to 3.3V.
GND_REF,
GND_48MHz,
GND_PCI,
GND_AGP,
GND_Core,
GND_CPU
2, 8, 29, 32, 37,
43
G
Ground Connections: Connect all ground pins to the common system ground
plane.
controller. For block write/read operation, the bytes must be
accessed in sequential order from lowest to highest byte with
Serial Data Interface
The CY28312B-2 features a two-pin, serial data interface that
can be used to configure internal register settings that control
particular device functions.
the ability to stop after any complete byte has been trans-
ferred. For byte/word write and byte read operations, system
controller can access individual indexed byte. The offset of the
indexed byte is encoded in the command code.
Data Protocol
The definition for the command code is defined in Table 1.
The clock driver serial protocol supports byte/word write,
byte/word read, block write and block read operations from the
Bit
Descriptions
7
0 = Block read or block write operation
1 = Byte/Word read or byte/word write operation
6:0
Byte offset for byte/word read or write operation. For block read or write operations, these bits
need to be set at ‘0000000’.
Table 1. Block Read and Block Write Protocol
Block Write Protocol
Block Read Protocol
Description
Bit
1
Description
Bit
1
Start
Start
2:8
9
Slave address – 7 bits
Write
2:8
9
Slave address – 7 bits
Write
10
Acknowledge from slave
10
Acknowledge from slave
11:18
Command Code – 8 bits
‘00000000’ stands for block operation
11:18
Command Code – 8 bits
‘00000000’ stands for block operation
19
20:27
28
Acknowledge from slave
Byte Count – 8 bits
19
20
Acknowledge from slave
Repeat start
Acknowledge from slave
Data byte 0 – 8 bits
21:27
28
Slave address – 7 bits
Read
29:36
37
Acknowledge from slave
Data byte 1 – 8 bits
29
Acknowledge from slave
Byte count from slave – 8 bits
Acknowledge
38:45
46
30:37
38
Acknowledge from slave
Rev 1.0,November 21, 2006
Page 3 of 17
SPECTRALINEAR [ SPECTRALINEAR INC ]
