UM11029
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© NXP Semiconductors N.V. 2017. All rights reserved.
User manual
Rev. 1.0 — 16 June 2017
339 of 515
NXP Semiconductors
UM11029
Chapter 19: LPC84x I2C0/1/2/3
19.6.2 I2C Status register
The STAT register provides status flags and state information about all of the functions of
the I
2
C block. Some information in this register is read-only and some flags can be cleared
by writing a 1 to them.
Access to bits in this register varies. RO = Read-only, W1 = write 1 to clear.
Details on the master and slave states described in the MSTSTATE and SLVSTATE bits in
this register are listed in
and
Table 352. I
2
C Status register (STAT, address 0x4005 0004 (I2C0), 0x4005 4004 (I2C1), 0x4003 0004 (I2C2), 0x4003
4004 (I2C3)) bit description
Bit
Symbol
Value Description
Reset
value
Access
0
MSTPENDING
Master Pending. Indicates that the Master is waiting to continue
communication on the I2C-bus (pending) or is idle. When the master
is pending, the MSTSTATE bits indicate what type of software service
if any the master expects. This flag will cause an interrupt when set if,
enabled via the INTENSET register. The MSTPENDING flag is not
set when the DMA is handling an event (if the MSTDMA bit in the
MSTCTL register is set). If the master is in the idle state, and no
communication is needed, mask this interrupt.
1
RO
0
In progress. Communication is in progress and the Master function is
busy and cannot currently accept a command.
1
Pending. The Master function needs software service or is in the idle
state. If the master is not in the idle state, it is waiting to receive or
transmit data or the NACK bit.
3:1
MSTSTATE
Master State code. The master state code reflects the master state
when the MSTPENDING bit is set, that is the master is pending or in
the idle state. Each value of this field indicates a specific required
service for the Master function. All other values are reserved.
0
RO
0x0
Idle. The Master function is available to be used for a new
transaction.
0x1
Receive ready. Received data available (Master Receiver mode).
Address plus Read was previously sent and Acknowledged by slave.
0x2
Transmit ready. Data can be transmitted (Master Transmitter mode).
Address plus Write was previously sent and Acknowledged by slave.
0x3
NACK Address. Slave NACKed address.
0x4
NACK Data. Slave NACKed transmitted data.
4
MSTARBLOSS
Master Arbitration Loss flag. This flag can be cleared by software
writing a 1 to this bit. It is also cleared automatically a 1 is written to
MSTCONTINUE.
0
W1
0
No loss. No Arbitration Loss has occurred.
1
Arbitration loss. The Master function has experienced an Arbitration
Loss.
At this point, the Master function has already stopped driving the bus
and gone to an idle state. Software can respond by doing nothing, or
by sending a Start in order to attempt to gain control of the bus when
it next becomes idle.
5
-
Reserved. Read value is undefined, only zero should be written.
NA
NA