mc33596 Freescale Semiconductor, Inc, mc33596 Datasheet - Page 19

• Manufacturer Part Number: mc33596
• Description: Pll Tuned Uhf Receiver For Data Transfer Applications
• Manufacturer: Freescale Semiconductor, Inc

Figure 9
Freescale Semiconductor
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OOK MODULATION (DSREF = 0)
OOK MODULATION (DSREF = 1)
FSK MODULATION (DSREF = 1)
NOTES:
1. The AGC settling time pulse can be split over different pulses as long as the overall duration is at least 200 μs.
2.
3. The Manchester 0 symbol can be replaced by a 1.
ID: The ID allows selection of the correct device in an RF transmission, as the content has been
loaded previously in the ID register. Its length is variable, defined by the IDL[1:0] bits. The
complement of the ID is also recognized as the identifier.
Header: The header specifies the beginning of the message, as it is compared with the HEADER
register. Its length is variable, defined by the HDL[1:0] bits. The complement of the header is also
recognized as the header, in this case, output data are complemented.
The ID and the header are sent at the same data rate as data.
Message: Data must follow the header, with no delay.
EOM: The message is completed with an end-of-message, consisting of two consecutive NRZ
ones or zeroes (i.e., a Manchester code violation). Even in the case of FSK modulation, data must
conclude with an EOM, and not simply by stopping the RF telegram.
Table 14
data and average filters cut-off frequencies.
shows a complete message comprising a 6-bit ID and a 4-bit header, followed by two data bits.
Data Slicer Reference Settling Time
1 NRZ >
1 NRZ >
AGC Settling Time
AGC Settling Time
At Least 3 Manchester
at Data Rate (2 and 3)
defines the minimum number of Manchester symbols required for the data slicer operation versus the
200
200
0 Symbols
Preamble
μs (1)
μs (1)
1
1
Clock Recovery
1 Manchester
0
at Data Rate
‘0’ Symbol
Figure 9. Complete Message Example
ID
0 1
Data Slicer Reference Settling Time
Figure 8. Preamble Definition
MC33596 Data Sheet, Rev. 3
Clock Recovery
at Data Rate (3)
At Least 3 Manchester
at Data Rate (2 and 3)
1 Manchester
1
0 Symbol
0 Symbols
ID
Preamble
ID
0
Header
1
Clock Recovery
at Data Rate (3)
1 Manchester
0 Symbol
1
0
1
Data
0
EOM
Communication Protocol
ID
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