Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
426
/
631
Figure 21-1 I
2
C functional block diagram
Note: in SMBus mode, SMBALERT is an optional signal. If SMBus is disabled, the signal cannot be used
Start and stop conditions
All data transfers always start with the start bit and end with the stop bit. The start and stop conditions are generated
by software in the master mode. Start bit is a level conversion from high to low on SDA line when SCL is high. Stop
bit is a level transition from low to high on SDA line when SCL is high. as shown in the figure below.
Figure 21-2 I2C bus protocol
Data
control
Clock
control
Shift register
Data register
PEC
calculation
Comparator
Dual address register
PEC register
Clock Control Register
Control
logic
Control Register
Status Register
SMBALERT
Interrupts DMA requests
Own address register
SDA
GPIO
SCL
GPIO
SDA
SCL
1
2
8
9
MSB
ACK
Start
condition
Stop
condition