UM10413
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© NXP B.V. 2011. All rights reserved.
User manual
Rev. 1 — 16 December 2011
116 of 268
NXP Semiconductors
UM10413
MPT612 User manual
16.4 Pin
description
16.5 I
2
C operating modes
In a given application, the I
2
C block can operate as a master, a slave, or both. In the slave
mode, the I
2
C hardware looks for its own slave address and the general call address. If
one of these addresses is detected, an interrupt is requested. If the processor wishes to
become the bus master, the hardware waits until the bus is free before the master mode is
entered so that a possible slave operation is not interrupted. If bus arbitration is lost in the
master mode, the I
2
C block switches to the slave mode immediately and can detect its
own slave address in the same serial transfer.
16.5.1 Master transmitter mode
In this mode, data is transmitted from master to slave. Before the master transmitter mode
can be entered, register I2CONSET must be initialized as shown in
. To enable
the I
2
C function, I2EN must be set to logic 1. If bit AA is logic 0, the I
2
C interface will not
acknowledge any address when another device is master of the bus, so it cannot enter
slave mode. The STA, STO and SI bits must be logic 0. Bit SI is cleared by writing logic 1
to bit SIC in register I2CONCLR.
The first byte transmitted contains the slave address of the receiving device (7 bits) and
the data direction bit. In this mode, the data direction bit (R/W) must be logic 0 which
means write. The first byte transmitted contains the slave address and write bit. Data is
Fig 26. I
2
C-bus configuration
pull-up
resistor
pull-up
resistor
SDA
SCL
SDA
SDA
MPT612
OTHER DEVICE WITH
I
2
C
INTERFACE
OTHER DEVICE WITH
I
2
C
INTERFACE
I
2
C
-bus
aaa-000589
Table 118. I
2
C pin description
Pin
Type
Description
SDA0,1
input/output
I
2
C serial data
SCL0,1
input/output
I
2
C serial clock
Table 119. I2C0CONSET and I2C1CONSET used to configure Master mode
Bit:
7
6
5
4
3
2
1
0
Symbol:
-
I2EN
STA
STO
SI
AA
-
-
Value:
-
1
0
0
0
0
-
-