Datasheet

ST7538Q Functional description
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Function Value Selection Note Default
Bit 13 Bit 12
12 to
13
Detection
Method
(1)
Carrier detection
without
conditioning
00
Carrier Detection
Notification on CD_PD
Line
CLR/T and RxD signal
always Present
Preamble
detection
without
conditioning
Carrier detection
with conditioning
01
CLR/T and RxD lines
are forced to “0” when
Carrier is not detected
Preamble
detection
without
conditioning
10
Preamble Detection
Notification on CD_PD
Line
CLR/T and RxD signal
always Present
Preamble
detection
with conditioning
11
Preamble Detection
Notification on CD_PD
Line
CLR/T and RxD lines
are forced to “0” when
Preamble has not been
detected or PLL is in
Unlock condition
Bit 14
14
Mains
Interfacing
Mode
Synchronous
Asynchronous
0
1
Asynchronou
s
Bit 16 Bit 15
15 to
16
Output Clock
16 MHz
8 MHz
4 MHz
Clock OFF
0
0
1
1
0
1
0
1
4 MHz
Bit 17
Active only if Extended
Control Register is
enable (Bit 21=”1”)
17
Output
Voltage Level
Freeze
Enabled
Disabled
0
1
Disabled
Bit 18
Active only if Extended
Control Register is
enable (Bit 21=”1”)
18
Header
Recognition
Disabled
Enabled
0
1
Disabled
Bit 19 Active only if Header
Recognition Function
(Bit 18=”1”) and
Extended Control
Register (Bit 21=”1”)
are enable
19
Frame
Length Count
Disabled
Enabled
0
1
Disabled
Table 11. Control register functions (continued)