MC9S08GB32 Motorola, MC9S08GB32 Datasheet - Page 207

• Manufacturer Part Number: MC9S08GB32
• Description: Microcontrollers
• Manufacturer: Motorola

13.2
This section provides a complete functional description of the IIC module.
13.2.1
The IIC bus 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. A 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:
The STOP signal should not be confused with the CPU STOP instruction. The IIC bus system
communication is described briefly in the following sections and illustrated in
Freescale Semiconductor
•
•
•
•
START signal
Slave address transmission
Data transfer
STOP signal
SDA
SCL
SDA
SCL
Functional Description
SIGNAL
SIGNAL
START
START
IIC Protocol
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
4
4
Figure 13-3. IIC Bus Transmission Signals
5
5
6
6
MC9S08GB/GT Data Sheet, Rev. 2.3
7
7
READ/
READ/
WRITE
WRITE
LSB
LSB
8
8
ACK
ACK
BIT
BIT
9
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
Inter-Integrated Circuit (IIC) Module
Figure
D2
6
6
D1
7
7
READ/
WRITE
13-3.
LSB
LSB
D0
8
8
ACK
NO
BIT
ACK
BIT
NO
9
9
SIGNAL
SIGNAL
STOP
STOP
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