Datasheet

176
7728G–AVR–06/10
ATtiny87/ATtiny167
15.5.9 xxERR Flags
LERR bit of the LINSIR register is an logical ‘OR’ of all the bits of LINERR register (see Sec-
tion 15.5.13 “Interrupts” on page 178). There are eight flags:
• LBERR = LIN Bit ERRor.
A unit that is sending a bit on the bus also monitors the bus. A LIN bit error will be flagged
when the bit value that is monitored is different from the bit value that is sent. After
detection of a LIN bit error the transmission is aborted.
• LCERR = LIN Checksum ERRor.
A LIN checksum error will be flagged if the inverted modulo-256 sum of all received data
bytes (and the protected identifier in LIN 2.1) added to the checksum does not result in
0xFF.
• LPERR = LIN Parity ERRor (identifier).
A LIN parity error in the IDENTIFIER field will be flagged if the value of the parity bits does
not match with the identifier value. (See LP[1:0] bits in Section 15.6.8 “LIN Identifier
Register - LINIDR” on page 186). A LIN slave application does not distinguish between
corrupted parity bits and a corrupted identifier. The hardware does not undertake any
correction. However, the LIN slave application has to solve this as:
- known identifier (parity bits corrupted),
- or corrupted identifier to be ignored,
- or new identifier.
• LSERR = LIN Synchronization ERRor.
A LIN synchronization error will be flagged if a slave detects the edges of the SYNCH field
outside the given tolerance.
• LFERR = LIN Framing ERRor.
A framing error will be flagged if dominant STOP bit is sampled.
Same function in UART mode.
• LTOERR = LIN Time Out ERRor.
A time-out error will be flagged if the MESSAGE frame is not fully completed within the
maximum length T
Frame_Maximum
by any slave task upon transmission of the SYNCH and
IDENTIFIER fields (see Section 15.5.10 “Frame Time Out” on page 177).
• LOVERR = LIN OVerrun ERRor.
Overrun error will be flagged if a new command (other than LIN Abort) is entered while
‘Busy signal’ is present.
In UART mode, an overrun error will be flagged if a received byte overwrites the byte stored
in the serial input buffer.
• LABORT
LIN abort transfer reflects a previous LIN Abort command (LCMD[2..0] = 000) while ‘Busy
signal’ is present.
After each LIN error, the LIN controller stops its previous activity and returns to its withdrawal
mode (LCMD[2..0] = 000
b
) as illustrated in Figure 15-11 on page 175.
Writing 1 in LERR of LINSIR register resets LERR bit and all the bits of the LINERR register.