CY28344
Table 3. Byte Read and Byte Write Protocol
Byte Write Protocol
Byte Read Protocol
Description
Bit
1
Description
Bit
1
Start
Start
2:8
9
Slave address – 7 bit
Write
2:8
9
Slave address – 7 bit
Write
10
Acknowledge from slave
10
Acknowledge from slave
11:18
Command Code – 8 bit
11:18
Command Code – 8 bit
“1xxxxxxx” stands for byte operation
bit[6:0] of the command code represents the
offset of the byte to be accessed
“1xxxxxxx” stands for byte operation
bit[6:0] of the command code represents the
offset of the byte to be accessed
19
20:27
28
Acknowledge from slave
Data byte – 8 bits
Acknowledge from slave
Stop
19
20
Acknowledge from slave
Repeat start
21:27
28
Slave address – 7 bits
Read
29
29
Acknowledge from slave
Data byte from slave – 8 bits
Not acknowledge
Stop
30:37
38
39
Data Byte Configuration Map
Data Byte 0
Power On
Default
Bit
Bit 7
Pin#
--
Name
Description
SEL3
SW Frequency selection bits. See Table 4.
0
0
0
0
0
Bit 6
Bit 5
Bit 4
Bit 3
--
SEL2
--
SEL1
--
SEL0
--
FS_Override
0 = Select operating frequency by FS[4:0] input pins
1 = Select operating frequency by SEL[4:0] settings
Bit 2
Bit 1
Bit 0
--
--
--
SEL4
SW Frequency selection bits. See Table 4.
0 = OFF; 1 = Enabled
0
0
0
Spread Spectrum Enable
Reserved
Reserved
Data Byte 1
Power On
Default
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Pin#
Name
Description
(Active/Inactive)
40, 39 CPU2, CPU2#
44, 43 CPU1, CPU1#
47, 46 CPU0, CPU0#
1
1
(Active/Inactive)
(Active/Inactive)
1
--
--
--
--
--
Latched FS4 input
Latched FS3 input
Latched FS2 input
Latched FS1 input
Latched FS0 input
Latched FS[4:0] inputs. These bits are Read-only.
X
X
X
X
X
Rev 1.0,November 21, 2006
Page 5 of 21
SPECTRALINEAR [ SPECTRALINEAR INC ]
