Chapter 10. I
2
C Interface
10-3
I
2
C Protocol
10.1.4 I
2
C Block Diagram
The reset state of the I
2
C interface is as a slave receiver. Thus, when not explicitly
programmed to be a master or to respond to a slave transmitter address, the I
2
C unit always
defaults to slave receiver operation. Figure 10-1 shows a block diagram of the I
2
C unit.
Figure 10-1. I
2
C Interface Block Diagram
10.2 I
2
C Protocol
A standard I
2
C transfer consists of four parts:
1. START condition
2. Slave target address transmission
3. Data transfer
4. STOP condition
Figure 10-2 shows the interaction of these four parts and the calling address, data byte, and
new calling address components of the I
2
C protocol. The details of the protocol are
described in the following subsections.
addr_reg
freq_reg
control_reg
status_reg
data_reg
addr_decode
data_mux
START,
STOP &
Arbitration
Control
Address
Compare
Input Sync
In/Out Data
Shift Register
Clock
Control
SCL
SDA
Address & Control
Interrupt
Data
Summary of Contents for MPC8240
Page 1: ...MPC8240UM D Rev 1 1 2001 MPC8240 Integrated Processor User s Manual ...
Page 38: ...xviii MPC8240 Integrated Processor User s Manual TABLES Table Number Title Page Number ...
Page 48: ...xlviii MPC8240 Integrated Processor User s Manual Acronyms and Abbreviations ...
Page 312: ...6 94 MPC8240 Integrated Processor User s Manual ROM Flash Interface Operation ...
Page 348: ...7 36 MPC8240 Integrated Processor User s Manual PCI Host and Agent Modes ...
Page 372: ...8 24 MPC8240 Integrated Processor User s Manual DMA Register Descriptions ...
Page 394: ...9 22 MPC8240 Integrated Processor User s Manual I2O Interface ...
Page 412: ...10 18 MPC8240 Integrated Processor User s Manual Programming Guidelines ...
Page 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Page 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Page 516: ...16 14 Watchpoint Trigger Applications ...
Page 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
Page 546: ...C 8 MPC8240 Integrated Processor User s Manual ...
Page 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...