RFM31 Datasheet, PDF (111/137 Pages) –

RFM31
Register 57h. Charge Pump Test
Bit
Name
Type
D7
pfdrst
R/w
D6
fbdiv_rst
R/w
D5
cpforceup
R/w
D4
cpforcedn
R/w
D3
cdonly
R/w
D2
D1
D0
cdcurr[2:0]
R/w
Reset value = 00000000
Bit
Name
7
pfdrst
6
fbdiv_rst
5
cpforceup
4
cpforcedn
3
cdonly
2:0
cdcurr[2:0]
Function
Direct Control to Analog.
Direct Control to Analog.
Charge Pump Force Up.
Charge Pump Force Down.
Charge Pump DC Offset Only.
Charge Pump DC Current Selection.
Register 58h. Charge Pump Current Trimming/Override
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Name
cpcurr[1:0]
cpcorrov
cporr[4:0]
Type
R/w
R/w
R/w
Reset value = 100xxxxx
Bit
Name
7:6
cpcurr[1:0]
5
cpcorrov
4:0
cporr[4:0]
Function
Charge Pump Current (Gain Setting).
Changing these bits will change the BW of the PLL. The default setting is
adequate for all data rates.
Charge Pump Correction Override Enable.
Charge Pump Correction Value.
During read, you read what the Charge Pump sees. If cpcorrov = 1, then the
value you write will go to the Charge Pump, and will also be the value you read.
By default, cpcorr[4:0] wakes up as all Zeros.
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