SM8702AM
I2C Bus Serial Data Format
The format of the I2C serial data on SDATA (pin 23) which is input in sync with the serial data clock on SCLK
(pin 24) is shown below.
The SM8702AM I2C address is given below.
A6 A5 A4 A3 A2 A1 A0 R/W#
1101001−
R/W# = 0 or 1
In the start sequence, the I2C bus serial data is fed into the clock generator in the following direction.
1. I2C address with R/W# = 0
2. ACK acknowledge bit
3. Two successive 8-bit dummy command code data words (including ACK acknowledge bit)
4. 8-bit dummy command code (Byte 0 to Byte 5)
The direction of I2C Data for Clock Generator
1bit 8bit 1bit 8bit 1bit 8bit 1bit 8bit 1bit 8bit 1bit
I2C Addr. A Dummy A Dummy A
A
A
A
+R/W# C Command C Command C Byte 0 C Byte 1 C Byte 2 C
D2h K Code K Code K
K
K
K
8bit 1bit
Byte 5
A
C
K
S
T
O
P
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
The data transfer speed is 100k bps (I2C standard mode), with input logic level of 3.3V. When power is first
applied, all internal registers are restored to their default state as below.
s Byte0 : default = 0 (bit 0 to bit 3 and bit 7)
: default = 1 (bit 4 to bit 6)
s Byte 1 to Byte 5 : default = 1 (all bits)
NIPPON PRECISION CIRCUITS—14