CY28301
Serial Data Interface
the controller. For block Write/Read operation, the bytes must
be accessed in sequential order from lowest to highest byte
with the ability to stop after any complete byte has been trans-
ferred. For byte/word Write and byte Read operations, the
system controller can access individual indexed bytes. The
offset of the indexed byte is encoded in the command code.
The CY28301 features a two-pin, serial data interface that can
be used to configure internal register settings that control
particular device functions.
Data Protocol
The definition for the command code is defined as follows.
The clock driver serial protocol supports byte/word Write,
byte/word Read, block Write, and block Read operations from
Table 1. Command Code Definition
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 2. 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
Data byte N/Slave acknowledge...
Data byte N – 8 bits
Acknowledge from slave
Stop
...
39:46
47
Data byte from slave – 8 bits
Acknowledge
...
...
48:55
56
Data byte from slave – 8 bits
Acknowledge
...
...
Data bytes from slave/acknowledge
Data byte N from slave – 8 bits
Not acknowledge
...
...
...
Stop
Rev 1.0,November 27, 2006
Page 3 of 13
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