si4420 Silicon Laboratories, si4420 Datasheet - Page 21

• Manufacturer Part Number: si4420
• Description: Si4420 Universal Ism Band Fsk Transceiver
• Manufacturer: Silicon Laboratories

13. Low Duty-Cycle Command
With this command, Low Duty-Cycle operation can be set in order to decrease the average power consumption in receiver mode.
The time cycle is determined by the Wake-Up Timer Command.
The Duty-Cycle can be calculated by using (d6 to d0) and M. (M is parameter in a Wake-Up Timer Command.)
Duty-Cycle= (D * 2 +1) / M *100%
Bit 0 (en): Enables the Low Duty-Cycle Mode. Wake-up timer interrupt not generated in this mode.
Note: In this operation mode, bit er must be cleared and bit ew must be set in the Power Management Command.
14. Low Battery Detector and Microcontroller Clock Divider Command
The 5 bit parameter (v4 to v0) represents the value V, which defines the threshold voltage V
V
Clock divider configuration:
The low battery detector and the clock output can be enabled or disabled by bits eb and dc, respectively, using the Power Management
Command.
lb
d2
Bit
Bit
= 2.25 + V * 0.1 [V]
0
0
0
0
1
1
1
1
d1
0
0
1
1
0
0
1
1
15
15
1
1
d0
0
1
0
1
0
1
0
1
Receiver
Xtal osc.
enable
14
14
DQD
1
1
On
13
13
0
0
Frequency [MHz]
Clock Output
12
12
0
0
1.25
1.66
3.33
2.5
10
1
2
5
11
11
1
0
2.25ms
Ton
10
10
0
0
Twake-up
9
0
9
0
8
0
8
0
d6
d2
7
7
d5
d1
6
6
Ton
d4
d0
5
5
Twake-up
d3
v4
4
4
d2
v3
3
3
lb
of the detector:
d1
v2
2
2
d0
v1
1
1
2.25ms
Ton
en
v0
Twake-up
0
0
C80Eh
C000h
POR
POR
Si4420
21