UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
1130 of 1269
NXP Semiconductors
UM10503
Chapter 43: LPC43xx I2C-bus interface
The master transmitter mode may now be entered by setting the STA bit. The I
2
C logic will
now test the I
2
C-bus and generate a START condition as soon as the bus becomes free.
When a START condition is transmitted, the serial interrupt flag (SI) is set, and the status
code in the status register (STAT) will be 0x08. This status code is used by the interrupt
service routine to enter the appropriate state service routine that loads DAT with the slave
address and the data direction bit (SLA+W). The SI bit in CON must then be reset before
the serial transfer can continue.
When the slave address and the direction bit have been transmitted and an
acknowledgment bit has been received, the serial interrupt flag (SI) is set again, and a
number of status codes in STAT are possible. There are 0x18, 0x20, or 0x38 for the
master mode and also 0x68, 0x78, or 0xB0 if the slave mode was enabled (AA = logic 1).
The appropriate action to be taken for each of these status codes is detailed in
.
After a Repeated START condition (state 0x10). The I
2
C block may switch to the master
receiver mode by loading DAT with SLA+R).