UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
1140 of 1269
NXP Semiconductors
UM10503
Chapter 43: LPC43xx I2C-bus interface
43.10.4 Slave Transmitter mode
In the slave transmitter mode, a number of data bytes are transmitted to a master receiver
(see
). Data transfer is initialized as in the slave receiver mode. When ADR and
CON have been initialized, the I
2
C block waits until it is addressed by its own slave
address followed by the data direction bit which must be “1” (R) for the I
2
C block to
operate in the slave transmitter mode. After its own slave address and the R bit have been
received, the serial interrupt flag (SI) is set and a valid status code can be read from STAT.
This status code is used to vector to a state service routine, and the appropriate action to
be taken for each of these status codes is detailed in
. The slave transmitter
mode may also be entered if arbitration is lost while the I
2
C block is in the master mode
(see state 0xB0).
If the AA bit is reset during a transfer, the I
2
C block will transmit the last byte of the transfer
and enter state 0xC0 or 0xC8. The I
2
C block is switched to the not addressed slave mode
and will ignore the master receiver if it continues the transfer. Thus the master receiver
receives all 1s as serial data. While AA is reset, the I
2
C block does not respond to its own
slave address or a General Call address. However, the I
2
C-bus is still monitored, and
address recognition may be resumed at any time by setting AA. This means that the AA
bit may be used to temporarily isolate the I
2
C block from the I
2
C-bus.