xe1205 Semtech Corporation, xe1205 Datasheet - Page 35

• Manufacturer Part Number: xe1205
• Description: Low-power, High Link Budget Integrated Uhf Transceiver
• Manufacturer: Semtech Corporation

7.2.8
Most of the parameters of this category are for test purposes. Some of them can be used to supersede settings that are
described in previous sections to optimize special applications. These last parameters are described in the table below.
Name
Add_BW
Low_BW
Code_BW(8:0)
Add_HPF(2:0)
Chg_OSR
OSR
© Semtech 2007
ADParam configuration register (additional settings)
Bits
1
2
6-0
7-6
5-3
4
7-0
Address
19
19
21
22
22
27
28
Table 25: Useful special settings from TParam register
RW
r/w
r/w
r/w
r/w
r/w
r/w
Description
Change of RXParam_BW(1:0) decoding, allowing additional
bandwidths for the base-band filter to be selected:
Add_BW = 0 -> default values of RXParam_BW(1:0):
RXParam_BW(1:0) = 00 => 10 kHz
RXParam_BW(1:0) = 01 => 20 kHz
RXParam_BW(1:0) = 10 => 40 kHz
RXParam_BW(1:0) = 11 => 200 kHz
Add_BW = 1 -> new bandwidth values:
RXParam_BW(1:0) = 00 => 14.3 kHz
RXParam_BW(1:0) = 01 => 28.5 kHz
RXParam_BW(1:0) = 10 => 66.7 kHz
RXParam_BW(1:0) = 11 => 100 kHz
Flag allowing selection of base-band filter bandwidths lower than 10
kHz:
0 -> default values given by RXParam_BW(1:0) and
1-> bandwidths defined by TParam_Code_BW(8:0)
Low base-band filter bandwidths, when TParam_Low_BW = 1:
Code_BW(8:0) = 139 => 9 kHz
Code_BW(8:0) = 160 => 8 kHz
Code_BW(8:0) = 185 => 7 kHz
MSB Code_BW(8) = bit 6 of address 21
Cut-off frequency of the HPF stages allowing cancellation of the DC
and low-frequency offsets in the baseband circuit:
0 0 0 -> 660 Hz (default value)
0 0 1 -> 1.48 kHz
0 1 0 -> 1.75 kHz
0 1 1 -> 1.96 kHz
1 0 0 -> 2.55 kHz
1 0 1 -> 3.34 kHz
1 1 0 -> 5.11 kHz
1 1 1 -> 10.2 kHz
Flag allowing the over-sampling ratio of the bit synchronizer to be
changed:
0 -> default OSR (32)
1 -> OSR defined by TParam_OSR(7:0)
Over-sampling ratio of the bit synchronizer when
TParam_Chg_OSR = 1
Actual OSR = TParam_OSR(7:0) + 1
TParam_Add_BW
35
XE1205
www.semtech.com