si4420 Silicon Laboratories, si4420 Datasheet - Page 18

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

8. Receiver FIFO Read Command
With this command, the controller can read 8 bits from the receiver FIFO. Bit 6 (ef) must be set in Configuration Setting Command.
9. AFC Command
Bit 7-6 (a1 to a0): Automatic operation mode selector:
Bit 5-4 (rl1 to rl0): Range limit. Limits the value of the frequency offset register to the next values:
Bit 3 (st): Strobe edge, when st goes to high, the actual latest calculated frequency error is stored into the offset register of the AFC block.
Bit 2 (fi):
Bit 1 (oe): Enables the frequency offset register. It allows the addition of the offset register to the frequency control word of the PLL.
Bit 0 (en): Enables the calculation of the offset frequency by the AFC circuit.
Bit
Bit
nSEL
SCK
SDI
SDO
15
15
1
1
Note: The transceiver is in receive (RX) mode when bit er is set using the Power Management Command
Switches the circuit to high accuracy (fine) mode. In this case, the processing time is about twice longer, but the measurement
uncertainty is about the half.
14
14
0
1
0
13
1
13
0
1
FFIT in RX mode / RGIT otherwise
12
1
12
0
2
rl1
0
0
1
1
a1
0
0
1
1
11
0
11
0
3
rl0
0
1
0
1
a0
0
1
0
1
10
0
10
1
4
Auto mode off (Strobe is controlled by microcontroller)
Runs only once after each power-up
Keep the f
Keep the f
9
0
9
0
5
+15 f
Max deviation
+7 f
No restriction
+3 f
8
0
res
res
8
0
res
6
offset
offset
to -16 f
to -8 f
to -4 f
7
0
only during receiving
value
a1
7
7
res
res
res
MSB
6
0
8
a0
6
5
0
9
rl1
5
f
315, 433 MHz bands: 2.5 kHz
868 MHz band: 5 kHz
915 MHz band: 7.5 kHz
res
4
0
10
:
rl0
4
received bits out
3
0
11
st
3
2
0
12
2
fi
13
1
0
oe
1
14
0
0
en
0
15
LSB
B000h
POR
C4F7h
POR
Si4420
18