DR
AFT
DR
AFT
DRAFT
DR
D
RAFT
DRAFT
DRA
FT DRAF
D
RAFT DRAFT DRAFT DRAFT DRAFT D
DRAFT
D
RAFT DRA
FT DRAFT DRAFT DRAFT DRA
UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
364 of 571
NXP Semiconductors
UM10316
Chapter 22: LPC29xx LIN 0/1
•
RXD/TXD line-clamped errors
All wake-up or error conditions can be enabled as interrupts.
Bit-errors and RXD/TXD line-clamped errors can only be detected when the LIN master is
actively transmitting. The only exception to this is that during reception of slave responses
stop-bit errors can also be detected.
In cases where bit errors are detected, the status of the bit error is signalled at the end of
the field in which it occurred and further transmission is then aborted.
shows in more detail when and under what conditions a bit error, an
RXD/TXD line-clamped error or a wake-up/LIN protocol error can occur.
3.4 Line-clamped detection versus bit-error detection
Depending on the situation when a line-clamped error is detected, it can be difficult to
distinguish between a line-clamped and a bit error. A typical situation could be that during
transmission of a LIN field the RXD or TXD line gets clamped permanently. In this case a
bit error will be detected first for this field since the differences between the transmitted
and received bits lead to this conclusion.
The LIN master aborts message transmission at the end of a field where a bit error was
detected.
To safely distinguish between a bit error and a line clamped error, the LIN master should
send a second message as soon as a bit error is detected. With the second message the
LIN master will be able to distinguish clearly between bit errors and line-clamped errors.
3.5 Wake-up interrupt handling
According to the LIN specification, any node in a sleeping LIN cluster may request a
wake-up. The wake-up request is issued by forcing the bus to dominant state for a period
of between 250 µs and 5 ms. When a LIN slave requests a wake-up by issuing a dominant
state the LIN master wake-up interrupt is asserted at the beginning of the dominant state.
Table 302. Error conditions and detection
Cause of error
occurrence
Condition
Error description
LIN master
Interrupt
flags
Error
capture
code
During LIN bus idle
Dominant level on RXD pin, RXD=0
RXD/TXD stuck dominant
WPI
Wake-up/Protocol error
Master is sending; HS=1 or TS=1
During every LIN field
No falling edge (start bit) on RXD pin
detected and RXD is recessive
RXD/TXD stuck recessive
RTLCEI
1000b
No falling edge (start bit) on RXD pin
detected and RXD is dominant
RXD/TXD stuck dominant
RTLCEI
1001b
LIN_RSR <> LIN_TSR
Bit error(s)
BEI
Master is receiving; RS=1
During response fields Stop bit = 0b
Dominant level during stop bit
BEI