si4021 Silicon Laboratories, si4021 Datasheet - Page 21

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

11. Status Register Read Command
With this command, it is possible to read the chip’s status register through the nIRQ pin. This command clears the last serviced interrupt and
processing the next pending one will start (if there is any).
12. PLL Setting and Reset Mode Command
Bits 7-6 <bw1 : bw0> select the PLL bandwidth:
Bit 1 (dr): Disables the highly sensitive RESET mode. If this bit is cleared, a 600 mV glitch in the power supply may cause a system reset. For
more detailed description see the Reset modes section.
bit
bit
bw1 bw0
Status Register Read Sequence
0
1
0
1
15
15
1
1
nSEL
nIRQ
SCK
SDI
1
1
0
0
14
14
1
1
Max datarate
0
13
13
0
0
[kbps]
115.2
19.2
38.4
68.9
1
12
12
0
1
2
11
11
1
0
Phase Noise at 1MHz offset
instruction
3
10
10
1
0
[dBc/Hz] (typical)
4
9
0
9
1
-112
-110
-107
-102
5
8
0
8
0
6
bw1
7
0
7
7
bw0
6
0
6
Charge pump current
POR
8
5
0
5
0
PB1
100%
25%
33%
50%
9
4
0
4
0
PB2
10
3
0
3
0
PB3
11
status out
2
0
2
0
PB4
12
dr
1
0
1
LBD
13
0
0
0
0
WK-UP
14
nIRQ
15
D200h
POR
POR
- -
IA4221
21