M451
May. 4, 2018
Page
686
of
1006
Rev.2.08
M4
51
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specification. The I
2
C port handles byte transfers autonomously. To enable this port, the bit
I2CEN in I2C_CTL should be set to '1'. The I
2
C hardware interfaces to the I
2
C bus via two pins:
SDA and SCL. When I/O pins are used as I
2
C ports, user must set the pins function to I
2
C in
advance.
Note:
Pull-up resistor is needed for I
2
C operation as the SDA and SCL are open-drain pins.
I
2
C Protocol
6.15.5.1
The Figure 6.15-3 shows the typical I
2
C protocol. Normally, a standard communication consists of
four parts:
START or Repeated START signal generation
Slave address and R/W bit transfer
Data transfer
STOP signal generation
SDA
SCL
1-7
8
9
S
1-7
8
9
1-7
8
9
P
ADDRESS
W/R
ACK
DATA
ACK
DATA
ACK
Figure 6.15-3 I
2
C Protocol
