Si4430
Preliminary Rev. 0.4
51
The clock recovery oversampling rate is set via rxosr[10:0] in "Register 20h. Clock Recovery Oversampling Rate"
and "Register 21h. Clock Recovery Offset 2".
ndec_exp and dwn3_bypass together with the receive data rate (Rb) are used to calculate rxosr:
Where: Rb is in kbps and enmanch is the Manchester Coding parameter. The resulting rxdr[10:0] value should be
rounded to an integer hexadecimal number.
The clock recovery offset ncoff[19:0] in "Register 21h. Clock Recovery Offset 2", "Register 22h. Clock Recovery
Offset 1", and "Register 23h. Clock Recovery Offset 0" is calculated as follows:
Where:
Rb
is in kbps.
The clock recovery gain crgain[10:0] in "Register 24h. Clock Recovery Timing Loop Gain 1" and "Register 25h.
Clock Recovery Timing Loop Gain 0" is calculated as follows:
Table 19. ndec[2:0] Settings
Rb(1+ enmanch) [kbps]
ndec[2:0]
Min
Max
0
1
5
1
2
4
2
3
3
3
8
2
8
40
1
40
65
0
)
1
(
2
_
3
2
1
500
3
exp
_
enmanch
Rb
bypass
dwn
rxosr
ndec
bypass
dwn
enmanch
Rb
ncoff
ndec
_
3
2
1
500
2
)
1
(
exp
_
20
rxosr
crgain
16
2
2
