NXP Semiconductors FXTH870 D Series, Руководство пользователя

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FXTH870xD
Sensors
96 Freescale Semiconductor, Inc.
Figure 67. Manchester Encoded Datagram for LFPOL = 0
When the LFPOL bit is set, a logic one bit is defined as LF carrier present for the first half of the bit time; and a logic zero bit is
defined as no LF carrier present for the first half of the bit time as shown in
Figure 68 .
Figure 68. Manchester Encoded Datagram for LFPOL = 1
12.11 Duty-Cycle For Data Mode
The definition of the duty-cycle for the Manchester encoded data depends on the relative rise and fall times of the incoming LF
carrier as shown in
Figure 69 .
Figure 69. Definition of Duty-Cycle of 40%
Regarding the SYNC pattern which is non-Manchester coded, the duty cycle is applied on all falling edges with the same
proportion as a 1T Manchester symbol, as shown in
Figure 70 .
T
0.5T
T
0.5T
LF Input
Logic “1” Logic “0”
Data Bit
Data Slicer Threshold
(shaded area
is LF
carrier)
(data slicer
output)
T = 1 Bit Time at the data rate (ex. 256 us at data rate of 3.906 kbps)
T
0.5T
T
0.5T
LF Input
Logic “0” Logic “1”
Data Bit
Data Slicer Threshold
(shaded area
is LF
carrier)
(data slicer
output)
T = 1 Bit Time at the data rate (ex. 256

s at data rate of 3.906 kbps)
40
60
60
1 0
40