Rf12b – Rainbow Electronics RF12B User Manual
Page 21
RF12B
Bit 4 (lpx): When this bit is set, low power mode of the crystal oscillator is selected.
lpx
Crystal start-up time (typ)
Power consumption (typ)
0
1 ms
620 uA
1
2 ms
460 uA
(Typ conditions: T
op
= 27
o
C; V
dd
= V
oc
= 2.7 V, Crystal ESR = 30 Ohm)
We have test that the default value(0) of bit lpx in PLL setting command will lead to
part of RF12B/RFM12B's oscillator fail. it should be set 1 in software manually. for
example, use 0xCC77 instead of 0xCC67 as PLL setting command.
Bit 3 (ddy): Switches on the delay in the phase detector when this bit is set.
Bit 2 (ddit): When set, disables the dithering in the PLL loop.
Bit 1-0 (bw1-bw0): PLL bandwidth can be set for optimal TX RF performance.
bw0
Max bit rate [kbps]
Phase noise at 1MHz offset [dBc/Hz]
0
86.2
-107
1
256
-102
13. Transmitter Register Write Command
bit 15 14 13 12 11 10
9
8
7 6 5 4
3 2 1 0 POR
1 0 1 1 1 0 0
0
t7
t6
t5
t4
t3
t2
t1
t0
B8AAh
With this command, the controller can write 8 bits (t7 to t0) to the transmitter data register. Bit 7 (el) must
be set in Configuration Setting Command.
Multiple byte write with Transmit Register Write Command:
Note:
Alternately the transmit register can be directly accessed by nFFSEL (pin6).
14. Wake-Up Timer Command
bit 15 14 13 12 11 10 9 8
7 6 5 4 3 2 1 0 POR
1 1 1 r4 r3 r2 r1
r0
m7
m6
m5
m4
m3
m2
m1
m0 E196h
The wake-up time period can be calculated by (m7 to m0) and (r4 to r0):
Tel: +86-755-86096587 Fax: +86-755-86096602 E-mail: [email protected] http://www.hoperf.com
T
= M * 2
R
[ms]
wake-up
Note:
•
For continual operation the et bit should be cleared and set at the end of every cycle.
•
For future compatibility, use R in a range of 0 and 29.
15. Low Duty-Cycle Command