MC68HC12 MOTOROLA [Motorola, Inc], MC68HC12 Datasheet - Page 304

• Manufacturer Part Number: MC68HC12
• Description: The MC68HC912DT128A microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit
• Manufacturer: MOTOROLA [Motorola, Inc]

Inter IC Bus
17.4 IIC System Configuration
17.5 IIC Protocol
Technical Data
304
SDA
SCL
SDA
SCL
Signal
Signal
Start
Start
MSB
MSB
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
1
1
2
2
Calling Address
Calling Address
3
3
The IIC system uses a Serial Data line (SDA) and a Serial Clock Line
(SCL) for data transfer. All devices connected to it must have open drain
or open collector outputs. Logic “and” function is exercised on both lines
with external pull-up resistors, the value of these resistors is system
dependent.
Normally, a standard communication is composed of four parts: START
signal, slave address transmission, data transfer and STOP signal. They
are described briefly in the following sections and illustrated in
2.
4
4
Figure 17-2. IIC Transmission Signals
5
5
6
6
7
7
Read/
Read/
Write
Write
LSB
LSB
8
8
Ack
Ack
Bit
9
Bit
Inter IC Bus
9
XX
Repeated
XXX
Signal
Start
MSB
MSB
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
D7
1
1
D6
2
2
New Calling Address
D5
3
3
Data Byte
D4
4
4
D3
5
5
MC68HC912DT128A — Rev 4.0
D2
6
6
D1
7
7
Read/
Write
LSB
LSB
D0
8
8
Ack
No
Bit
Ack
9
No
9
Bit
MOTOROLA
Signal
Figure 17-
Stop
Signal
Stop