Si4021

13

Control Commands

Control Command

Related Parameters/Functions

Related control bits

1

Configuration Setting Command

Frequency band, microcontroller clock output, crystal

load capacitance, frequency deviation

b1 to b0, d2 to d0, x3

to x0, ms, m2 to m0

2

Power Management Command

Crystal oscillator, synthesizer, power amplifier, low

battery detector, wake-up timer, clock output buffer

a1 a0, ex, es, ea, eb,

et, dc

3

Frequency Setting Command

Carrier frequency

f11 to f0

4

Data Rate Command

Bit rate

r7 to r0

5

Power Setting Command

Nominal output power, OOK mode

ook, p2 to p0

6

Low Battery Detector Command

Low battery threshold limit, transmit bit synchronizer,

wake-up timer calibration

dwc, ebs, t4 to t0

7

Sleep Command

Length of the clock tail after power down

s7 to s0

8

Push-Button Command

Push-button related functions

p4, d1 to d0, b4 to b1,

bc

9

Wake-Up Timer Command

Wake-up time period

r4 to r0, m7 to m0

10

Data Transmit Command

Data transmission

11

Status Register Command

Transmitter status read

12

PLL Setting and Reset Mode Command

PLL bandwidth, reset mode

bw1 to bw0, dr

Note: In the following tables the POR column shows the default values of the command registers after power-on.

1. Configuration Setting Command

bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

POR

1

0

0

b1

b0

d2

d1

d0

x3

x2

x1

x0

ms

m2

m1

m0

8080h

b1

b0

Frequency Band {MHz]

0

0

315

0

1

433

1

0

868

1

1

915

Clock Output

Frequency [MHz]

0

0

0

1

0

0

1

1.25

0

1

0

1.66

0

1

1

2

1

0

0

2.5

1

0

1

3.33

1

1

0

5

1

1

1

10

d2

d1

d0

x3

x2

x1

x0

Crystal Load Capacitance [pF]

0

0

0

0

8.5

0

0

0

1

9.0

0

0

1

0

9.5

0

0

1

1

10.0

1

1

1

0

15.5

1

1

1

1

16.0

…

The resulting output frequency can be calculated as:

f

SIGN

* (M + 1) * (30 kHz)

where:

f

M is the three bit binary number <m2 : m0>

SIGN = (ms) XOR (FSK input)

Note:



Use M in a range from 0 to 6.