UM10503
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
1129 of 1269
NXP Semiconductors
UM10503
Chapter 43: LPC43xx I2C-bus interface
, circles are used to indicate when the serial interrupt flag is
set. The numbers in the circles show the status code held in the STAT register. At these
points, a service routine must be executed to continue or complete the serial transfer.
These service routines are not critical since the serial transfer is suspended until the serial
interrupt flag is cleared by software.
When a serial interrupt routine is entered, the status code in STAT is used to branch to the
appropriate service routine. For each status code, the required software action and details
of the following serial transfer are given in tables from
43.10.1 Master Transmitter mode
In the master transmitter mode, a number of data bytes are transmitted to a slave receiver
(see
). Before the master transmitter mode can be entered, CON must be
initialized as follows:
The I
2
C rate must also be configured in the SCLL and SCLH registers. I2EN must be set
to logic 1 to enable the I
2
C block. If the AA bit is reset, the I
2
C block will not acknowledge
its own slave address or the General Call address in the event of another device
becoming master of the bus. In other words, if AA is reset, the I
2
C interface cannot enter
slave mode. STA, STO, and SI must be reset.
Table 996. Abbreviations used to describe an I
2
C operation
Abbreviation
Explanation
S
START Condition
SLA
7-bit slave address
R
Read bit (HIGH level at SDA)
W
Write bit (LOW level at SDA)
A
Acknowledge bit (LOW level at SDA)
A
Not acknowledge bit (HIGH level at SDA)
Data
8-bit data byte
P
STOP condition
Table 997. CONSET used to initialize Master Transmitter mode
Bit
7
6
5
4
3
2
1
0
Symbol
-
I2EN
STA
STO
SI
AA
-
-
Value
-
1
0
0
0
x
-
-
