mc9s08gt32a Freescale Semiconductor, Inc, mc9s08gt32a Datasheet - Page 213

• Manufacturer Part Number: mc9s08gt32a
• Description: Hcs08 Microcontrollers 8-bit Microcontroller Family
• Manufacturer: Freescale Semiconductor, Inc

13.4
This section provides a complete functional description of the IIC module.
13.4.1
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
SDA
SCL
SDA
SCL
•
•
•
•
SIGNAL
SIGNAL
START
START
START signal
Slave address transmission
Data transfer
STOP signal
MSB
MSB
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
Functional Description
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
1
1
IIC Protocol
2
2
CALLING ADDRESS
CALLING ADDRESS
3
3
4
4
5
5
6
6
Figure 13-8. IIC Bus Transmission Signals
7
7
READ/
WRITE
READ/
MC9S08GB60A Data Sheet, Rev. 1.02
WRITE
LSB
LSB
8
8
ACK
ACK
BIT
BIT
9
9
XX
REPEATED
SIGNAL
XXX
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
D2
6
6
D1
7
7
Figure
READ/
WRITE
LSB
LSB
D0
8
8
ACK
BIT
NO
ACK
BIT
NO
9
9
13-8.
SIGNAL
SIGNAL
STOP
STOP
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