UM10413
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© NXP B.V. 2011. All rights reserved.
User manual
Rev. 1 — 16 December 2011
115 of 268
NXP Semiconductors
UM10413
MPT612 User manual
•
Arbitration is handled between simultaneously transmitting masters without corruption
of serial data on the bus
•
Programmable clock allows adjustment of I
2
C transfer rates
•
Data transfer is bidirectional between masters and slaves
•
Serial clock synchronization allows devices with different bit rates to communicate via
one serial bus
•
Serial clock synchronization is used as a handshake mechanism to suspend and
resume serial transfer
•
I
2
C-bus can be used for test and diagnostic purposes
16.2 Applications
Interfaces to external I
2
C standard parts, such as serial RAMs, LCDs and tone
generators.
16.3 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 with a
Stop condition or with a repeated Start condition. Since a repeated Start condition is
also the beginning of the next serial transfer, the I
2
C-bus is not released.
The MPT612 I
2
C interfaces are byte oriented and have four operating modes: master
transmitter mode, master receiver mode, slave transmitter mode and slave receiver
mode.
The I
2
C interfaces comply with the entire I
2
C specification, supporting the ability to turn off
power to the MPT612 without interfering with other devices on the same I
2
C-bus.