XE8806A SEMTECH [Semtech Corporation], XE8806A Datasheet - Page 88

• Manufacturer Part Number: XE8806A
• Description: Ultra Low-Power Low-Voltage
• Manufacturer: SEMTECH [Semtech Corporation]

14.8.2.1
In this case, the interface will not look for a start sequence. The incoming data stream will be decoded according to
the selected PCM code and will be stored in the reception FIFO as soon as the reception mode is enabled. The
message start has to be detected by software.
14.8.2.2
The NRZ coding has no defined start sequence. Selecting the “protocol” start sequence in NRZ has the same
effect as no start detection.
In the bi-phase or Manchester code, any protocol violation is considered as a start sequence i.e. a 1-level or 0-level
which is longer than the duration of a chip. An example is shown in Figure 14-3.
In the delay modulation or Miller coding, any protocol violation is considered as a start sequence i.e. a 1-level or 0-
level which is longer than the duration of 2 chips.
Figure 14-3 : Start sequence type in Bi-Phase-Level encoding
14.8.2.3
An external start detection signal can be used. This signal should be connected to the pin RFIF2. The falling edge
of RFIF2 (also called “match”, see Figure 14-1) indicates the first valid bit of the message. This edge has to occur
during the first half of the first bit as shown in Figure 14-4. The minimal width of the pulse is half a bit.
© Semtech 2006
Bi-Phase - Level
“Protocol” start detection
“External” start detection
No start sequence detection
codes
1
bit sequence
1
Table 14-13. Start detection mode selection
0
1
“pattern 8bits”
1
“protocol”
“external”
0
“None”
name
start detection mode
0
0
1
start sequence
1
14-8
5 x '1'
RfifEnStart[1:0]
1
1
00
01
10
11
first valid bit
1
0
0
1
0
sequence
3 x '0'
other
start
0
XE8806A/XE8807A
0
first valid bit
1
1
0
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