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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
381 of 571
1.
How to read this chapter
The contents of this chapter apply to all LPC29xx parts.
2.
Features
•
I
2
C0 and I
2
C1 use standard I/O pins with bit rates of up to 400 kbit/s (Fast I
2
C-bus)
and do not support powering off of individual devices connected to the same bus
lines.
•
Easy to configure as master, slave, or master/slave.
•
Programmable clocks allow versatile rate control.
•
Bidirectional data transfer between masters and slaves.
•
Multi-master bus (no central master).
•
Arbitration between simultaneously transmitting masters without corruption of serial
data on the bus.
•
Serial clock synchronization allows devices with different bit rates to communicate via
one serial bus.
•
Serial clock synchronization can be used as a handshake mechanism to suspend and
resume serial transfer.
•
The I
2
C-bus can be used for test and diagnostic purposes.
•
All I
2
C-bus controllers support multiple address recognition and a bus monitor mode.
3.
Applications
Interfaces to external I
2
C standard parts, such as serial RAMs, LCDs, tone generators,
etc.
4.
Description
A typical I
2
C bus configuration is shown in
. Depending on the state of the
direction bit (R/W), two types of data transfers are possible on the I
2
C bus:
•
Data transfer from a master transmitter to a slave receiver. The first byte transmitted
by the master is the slave address. Next follows a number of data bytes. The slave
returns an acknowledge bit after each received byte.
•
Data transfer from a slave transmitter to a master receiver. The first byte (the slave
address) is transmitted by the master. The slave then returns an acknowledge bit.
Next follows the data bytes transmitted by the slave to the master. The master returns
an acknowledge bit after all received bytes other than the last byte. At the end of the
last received byte, a “not acknowledge” is returned. The master device generates all
of the serial clock pulses and the START and STOP conditions. A transfer is ended
UM10316
Chapter 23: LPC2xx I2C-interface
Rev. 00.06 — 17 December 2008
User manual