AS3930 データシートの表示（PDF） - austriamicrosystems AG
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AS3930 Datasheet PDF : 32 Pages
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AS3930
Datasheet - Detailed Description
Table 19. Bit Rate Setup
R7<4> R7<3> R7<2>
1
1
1
1
1
1
R7<1>
1
1
R7<0>
0
1
Bit Duration in RTC
Clock Periods
31
32
Bit Rate (bits/s)
1056
1024
Symbol Rate
(Manchester symbols/s)
528
512
If the preamble is detected correctly the correlator keeps searching for a data pattern. The duration of the preamble plus the pattern should not
be longer than 40 bits (see bit rate definition in Table 19). The data pattern can be defined by the user and consists of two bytes which are stored
in the registers R5<7:0> and R6<7:0>. The two bytes define the pattern consisting of 16 half bit periods. This means the pattern and the bit
period can be selected by the user. The only limitation is that the pattern (in combination with preamble) must obey Manchester coding and
timing. It must be noted that according to Manchester coding a down-to-up bit transition represents a symbol "0", while a transition up-to-down
represents a symbol "1". If the default code is used (96 [hex]) the binary code is (10 01 01 10 01 10 10 01). MSB has to be transmitted first.
The user can also select (R1<2>) if single or double data pattern is used for wake-up. In case double pattern detection is set, the same pattern
has to be repeated 2 times.
Additionally, it is possible to set the number of allowed missing zero bits (not symbols) in the received bitstream (R2<6:5>), as shown in the
Table 20.
Table 20. Allowed Pattern Detection Errors
R2<6>
R2<5>
Maximum allowed error in the pattern detection
0
0
No error allowed
0
1
1 missed zero
1
0
2 missed zeros
1
1
3 missed zeros
If the pattern is matched, then the wake-up interrupt is displayed on the WAKE output.
If the pattern detection fails, then the internal wake-up is terminated with no signal sent to MCU and the false wake-up register will be
incremented (R13<7:0>).
The wake-up state is terminated with the direct command ‘clear_wake’ (see Table 12). This command terminates the MCU activity. The
termination can also be automatic in case there is no response from MCU. The time out for automatic termination is set in a register R7<7:5>,
as shown in the Table 21.
Table 21. Timeout Setup
R7<7>
R7<6>
R7<5>
Timeout
0
0
0
0 sec
0
0
1
50 msec
0
1
0
100 msec
0
1
1
150 msec
1
0
0
200 msec
1
0
1
250 msec
1
1
0
300 msec
1
1
1
350 msec
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Revision 1.5
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