Rainbow-electronics ATmega64C1 Manuel d'utilisateur télécharger pdf (Page 213)

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7647A–AVR–02/08

ATmega32/64/M1/C1

Figure 17-8. Handling LBT[5..0]

17.5.7 Data Length

Section 17.4.6 “LIN Commands” on page 207 describes how to set or how are automatically set

the LRXDL[3..0] or LTXDL[3..0] fields of LINDLR register before receiving or transmitting a

response.

In the case of Tx Response the LRXDL[3..0] will be used by the hardware to count the number of

bytes already successfully sent.

In the case of Rx Response the LTXDL[3..0] will be used by the hardware to count the number of

bytes already successfully received.

If an error occurs, this information is useful to the programmer to recover the LIN messages.

17.5.7.1 Data Length in LIN 2.1

• If LTXDL[3..0]=0 only the CHECKSUM will be sent,

• If LRXDL[3..0]=0 the first byte received will be interpreted as the CHECKSUM,

• If LTXDL[3..0] or LRXDL[3..0] >8, values will be forced to 8 after the command setting and

before sending or receiving of the first byte.

17.5.7.2 Data Length in LIN 1.3

• LRXDL and LTXDL fields are both hardware updated before setting LIDOK by decoding the

data length code contained in the received PROTECTED IDENTIFIER (LRXDL = LTXDL).

• Via the above mechanism, a length of 0 or >8 is not possible.

Write in LINBTR register

LENA ?

(LINCR bit 4)

LDISR

to write

LBT[5..0] forced to 0x20

LDISR forced to 0

Enable re-synch. in LIN mode

LBT[5..0] = LBT[5..0] to write

(LBT[5..0]

min

=8)

LDISR forced to 1

Disable re-synch. in LIN mode

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Rainbow-electronics ATmega64C1 Manuel d'utilisateur Page 213