Atmel Xplained Evaluation Board AT32UC3A3-XPLD AT32UC3A3-XPLD データシート

32072H–AVR32–10/2012

• LINMR.DLM=1: the response data length is defined by the Identifier (LINIR.IDCHR) bits 

according to the table below.

The last frame field is the checksum. It is configured by the Checksum Type (LINMR.CHKTYP),
and the Checksum Disable (LINMR.CHKDIS) bits. CSR.TXRDY will not be set after the last THR
data write if enabled. Writing a one to LINMR.CHKDIS will disable the automatic checksum gen-
eration/checking, and the user may send/check this last byte manually, disguised as a normal
data. The checksum is an inverted 8-bit sum with carry, either:

• Over all data bytes, called a classic checksum. This is used for LIN 1.3 compliant slaves, and 

automatically managed when CHKDIS=0, and CHKTYP=1.

• Over all data bytes and the protected identifier, called an enhanced checksum. This is used 

for LIN 2.0 compliant slaves, and automatically managed when CHKDIS=0, and CHKTYP=0.

A LIN master can be configured to use frame slots with a pre-defined minimum length. This
Frame Slot mode is enabled by default, and is disabled by writing a one to the Frame Slot Mode
Disable bit (LINMR.FSDIS). The Frame Slot mode will not allow CSR.TXRDY to be set after a
frame transfer until the entire frame slot duration has elapsed, in effect preventing the master
from sending a new header. The LIN Transfer Complete bit (CSR.LINTC) will still be set after the
checksum has been sent. An interrupt is generated if the LIN Transfer Complete bit in the Inter-
rupt Mask Register (IMR.LINTC) is set. Writing a one to CR.RSTSTA clears CSR.LINTC.

Figure 25-32. Frame Slot Mode with Automatic Checksum

Table 25-14. Response Data Length if DLM = 1

0

0

2

0

1

2

1

0

4

1

1

8

Break

Synch

Protected

Identifier

Data N

Checksum

Header

Inter-

frame

space

Response

space

Frame

Frame slot = TFrame_Maximum

Response

TXRDY

Write
THR

Write
LINID

Data 1

Data 2

Data 3

Data3

Data N-1

Data N

Frame Slot Mode

Disabled

Frame Slot Mode

Enabled

LINTC

Data 1