si4021 Silicon Laboratories, si4021 Datasheet - Page 13

• Manufacturer Part Number: si4021
• Description: Si4021 Universal Ism Band Fsk Transmitter
• Manufacturer: Silicon Laboratories

Control Commands
Note: In the following tables the POR column shows the default values of the command registers after power-on.
1. Configuration Setting Command
d2
b1
10
11
12
bit
0
0
1
1
0
0
0
0
1
1
1
1
1
2
3
4
5
6
7
8
9
d1
Control Command
Configuration Setting Command
Power Management Command
Frequency Setting Command
Data Rate Command
Power Setting Command
Low Battery Detector Command
Sleep Command
Push-Button Command
Wake-Up Timer Command
Data Transmit Command
Status Register Command
PLL Setting and Reset Mode Command
b0
0
1
0
1
0
0
1
1
0
0
1
1
15
1
d0
0
1
0
1
0
1
0
1
Frequency Band {MHz]
14
0
13
0
315
433
868
915
Frequency [MHz]
Clock Output
12
b1
1.25
1.66
3.33
2.5
10
11
b0
1
2
5
10
d2
d1
9
d0
8
Related Parameters/Functions
Frequency band, microcontroller clock output, crystal
load capacitance, frequency deviation
Crystal oscillator, synthesizer, power amplifier, low
battery detector, wake-up timer, clock output buffer
Carrier frequency
Bit rate
Nominal output power, OOK mode
Low battery threshold limit, transmit bit synchronizer,
wake-up timer calibration
Length of the clock tail after power down
Push-button related functions
Wake-up time period
Data transmission
Transmitter status read
PLL bandwidth, reset mode
x3
7
x2
6
The resulting output frequency can be calculated as:
where:
Note:
x1
5
x3
0
0
0
0
1
1
f
f
M is the three bit binary number <m2 : m0>
SIGN = (ms) XOR (FSK input)
•
out
0
is the channel center frequency (see the next command)
x2
x0
= f
4
0
0
0
0
1
1
Use M in a range from 0 to 6.
0
– (-1)
x1
ms
0
0
1
1
1
1
3
SIGN
x0
0
1
0
1
0
1
m2
* (M + 1) * (30 kHz)
2
Crystal Load Capacitance [pF]
m1
1
…
m0
0
10.0
15.5
16.0
8.5
9.0
9.5
8080h
Related control bits
b1 to b0, d2 to d0, x3
to x0, ms, m2 to m0
a1 a0, ex, es, ea, eb,
et, dc
f11 to f0
r7 to r0
ook, p2 to p0
dwc, ebs, t4 to t0
s7 to s0
p4, d1 to d0, b4 to b1,
bc
r4 to r0, m7 to m0
bw1 to bw0, dr
POR
IA4221
13