AT32UC3C1512C Automotive Atmel Corporation, AT32UC3C1512C Automotive Datasheet - Page 605

• Manufacturer Part Number: AT32UC3C1512C Automotive
• Manufacturer: Atmel Corporation

25.6.9.9
9166C–AVR-08/11
Identifier Parity
F
LIN Standard imposes that it must not exceed ±15%. The LIN Standard imposes also that for
communication between two nodes, their bit rate must not differ by more than ±2%. This means
that the Baudrate_deviation must not exceed ±1%.
It follows from that, a minimum value for the nominal clock frequency:
Examples:
If the fractional baud rate is not used, the accuracy of the synchronization becomes much lower.
When the counter is stopped, the 16 most significant bits of the counter (value divided by 8)
gives the new clock divider (CD). This value is rounded by adding the first insignificant bit. The
equation of the Baudrate deviation is the same as given above, but the constants are as follows:
It follows from that, a minimum value for the nominal clock frequency:
Examples:
A protected identifier consists of two sub-fields; the identifier and the identifier parity. Bits 0 to 5
are assigned to the identifier and bits 6 and 7 are assigned to the parity.
The USART interface can generate/check these parity bits, but this feature can also be disabled.
The user can choose between two modes by the PARDIS bit of the LIN Mode register (LINMR):
TOL_UNSYNCH
• Baudrate = 20 kbit/s, Over=0 (Oversampling 16X) => F
• Baudrate = 20 kbit/s, Over=1 (Oversampling 8X) => F
• Baudrate = 1 kbit/s, Over=0 (Oversampling 16X) => F
• Baudrate = 1 kbit/s, Over=1 (Oversampling 8X) => F
• Baudrate = 20 kbit/s, Over=0 (Oversampling 16X) => F
• Baudrate = 20 kbit/s, Over=1 (Oversampling 8X) => F
• Baudrate = 1 kbit/s, Over=0 (Oversampling 16X) => F
• Baudrate = 1 kbit/s, Over=1 (Oversampling 8X) => F
is the deviation of the real slave node clock from the nominal clock frequency. The
Baudrate_deviation
F
F
NOM
NOM
(
(min)
min
)
=
=
⎛
⎜
⎜
⎜
⎝
⎛
⎜
⎜
⎜
⎝
100
100
×
×
=
[
------------------------------------------------------------------------------------------ -
4
[
----------------------------------------------------------------------------------------------- -
⎛
⎜
⎜
⎜
⎝
0.5
×
100
–
–
8
4
0.5
×
×
≤
8
(
×
8
α +4
2 Over
×
≤
α [
-------------------------------------------------------------------------------------------- -
×
–
≤
8
⎛
⎝
α +0.5
–
--------- -
100
(
×
15
2 Over
≤
×
8
⎛
⎝
–
8
–
--------- -
100
+
×
)
15
×
1
-1 β
+
⎛
⎝
⎞
⎠
(
F
-------------------------------------- -
1
2 Over
+
<
×
TOL_UNSYNCH
] Baudrate
Nom
Nom
–
)
1%
1
×
-1
Nom
Nom
Nom
Nom
+
⎞
⎠
<
Nom
Nom
(min) = 74 kHz
(min) = 485 kHz
100
×
1
+1
<
(min) = 1.47 MHz
(min) = 132 kHz
(min) = 9.71 MHz
(min) = 956 kHz
] Baudrate
1%
β
(min) = 2.64 MHz
(min) = 19.12 MHz
×
)
<
+ ]
+1
β
⎞
⎟
⎟
⎟
⎠
Hz
⎞ xF
⎠
×
Baudrate
Nom
⎞
⎟
⎟
⎟
⎠
Hz
AT32UC3C
⎞
⎟
⎟
⎟
⎠
%
605