SAM4L Datasheet, PDF (595/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
24.6.10.8
–4 ≤ α ≤ +4 -1 < β < +1
Minimum nominal clock frequency without a fractional part:
⎛
⎞
F_Nom ( min )
=
⎜
⎜100
×
-^[--⁴-----^×-----⁸----^×-----⁽---²----–-----^O-----^V----^E----^R----⁾----+-----¹----^]---^×-----^B----^a---^u----^d---^r--^a---^t--^e--_⎟⎟
Hz
⎜
⎝
8
×
⎛
⎝
-–---¹---⁵--
100
+
1_⎠⎞
×
1%
⎟
⎠
Examples:
• Baud rate = 20 kbit/s, OVER=0 (Oversampling 16x) => F_Nom(min) = 19.12MHz
• Baud rate = 20 kbit/s, OVER=1 (Oversampling 8x) => F_Nom(min) = 9.71MHz
• Baud rate = 1 kbit/s, OVER=0 (Oversampling 16x) => F_Nom(min) = 956 kHz
• Baud rate = 1 kbit/s, OVER=1 (Oversampling 8x) => F_Nom(min) = 485 kHz
Identifier Parity
An identifier field consists of two sub-fields; the identifier and its parity. Bits 0 to 5 are assigned
to the identifier, while bits 6 and 7 are assigned to parity. Automatic parity management is
enabled by default, and can be disabled by writing a one to the Parity Disable bit in the LIN
Mode register (LINMR.PARDIS).
• LINMR.PARDIS=0: During header transmission, the parity bits are computed and in the shift
register they replace bits 6 and 7 from LINIR.IDCHR. During header reception, the parity bits
are checked and can generate a LIN Identifier Parity Error (see Section 24.6.10.13). Bits 6
and 7 in LINIR.IDCHR read as zero when receiving.
• LINMR.PARDIS=1: During header transmission, all the bits in LINIR.IDCHR are sent on the
bus. During header reception, all the bits in LINIR.IDCHR are updated with the received
Identifier.
24.6.10.9
Node Action
After an identifier transaction, a LIN response mode must be selected. This is done in the Node
Action field (LINMR.NACT). Below are some response modes exemplified in a small LIN cluster:
• Response, from master to slave1:
Master: NACT=PUBLISH
Slave1: NACT=SUBSCRIBE
Slave2: NACT=IGNORE
• Response, from slave1 to master:
Master: NACT=SUBSCRIBE
Slave1: NACT=PUBLISH
Slave2: NACT=IGNORE
• Response, from slave1 to slave2:
Master: NACT=IGNORE
Slave1: NACT=PUBLISH
Slave2: NACT=SUBSCRIBE
42023C–SAM–02/2013
595