SI598 Datasheet, PDF (18/28 Pages) Silicon Laboratories – Programmable with 28 parts per trillion frequency resolution

Si598/Si599
Register 12. Reference Frequency
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Name
RFREQ[7:0]
Type
R/W
Bit
Name
7:0 RFREQ[7:0] Reference Frequency.
Frequency control input to DCO.
Function
Register 135. NewFreq/Freeze/Memory Control
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Name
NewFreq Freeze M
Freeze
VCADC
RECALL
Type
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset settings = 00xxxx00
Bit
Name
Function
7
Reserved This bit should read 0 in normal operation.
6
NewFreq New Frequency Applied.
Alerts the DSPLL that a new frequency configuration has been applied. This bit will
clear itself when the new frequency is applied. Write 0x40 to this register to assert
NewFreq.
5
Freeze M Freezes the M Control Word.
Prevents interim frequency changes when writing RFREQ registers.
4
Freeze Freezes the VCDADC Output Word.
VCADC _{May be used to hold the nominal output frequency of the Si599. Do not use with Si598.}
3:1
Reserved Always zero.
0
RECALL Recall NVM into RAM.
0 = No operation.
1 = Write NVM bits into RAM. Bit is internally reset following completion of operation.
18
Rev. 1.0