Single-Chip Low Power RF Transceiver for Narrowband Systems ...

CC1021
CLOCK_B Register (0Bh)
REGISTER NAME Default
value
Active Description
C LOCK_B[7:5] REF_DIV_B[2:0] 2 - Reference frequency divisor (B):
0: Not supported
1: REF_CLK frequency
= Crystal frequency / 2
…
7: REF_CLK frequency = Crystal frequency / 8
CLOCK_B[4:2] MCLK_DIV1_B[2:0] 4 - Modem clock divider 1 (B):
0: Divide by 2.5
1: Divide by 3
2: Divide by 4
3: Divide by 7.5 (2.5·3)
4: Divide by 12.5 (2.5·5)
5: Divide
by 40 (2.5·16)
6: Divide by 48 (3·16)
7: Divide by 64 (4·16)
CLOCK_B[1:0] MCLK_DIV2_B[1:0] 0 - Modem clock divider
2 (B):
0: Divide by 1
1: Divide by 2
2: Divide by 4
3: Divide by 8
MODEM_CLK frequency is FREF frequency
divided by
the product of divider 1 and divider 2.
Baud rate is MODEM_CLK frequency divided by 8.
VCO Register (0Ch)
REGISTER NAME Default
value
Active Description
VCO[7:4] VCO_CURRENT_A[3:0] 8 - Control of
current in VCO core for frequency A
0: 1.4 mA current
in VCO core
1: 1.8 mA current in VCO core
2: 2.1 mA current in VCO core
3: 2.5 mA current in VCO core
4: 2.8 mA current in VCO core
5: 3.2 mA current in VCO core
6: 3.5 mA current in VCO core
7: 3.9 mA current in VCO core
8: 4.2 mA current in VCO core
9: 4.6 mA current in VCO core
10: 4.9 mA current in VCO core
11: 5.3 mA current in VCO core
12: 5.6 mA current in VCO core
13: 6.0 mA current in VCO core
14: 6.4 mA current in VCO core
15: 6.7 mA current in VCO core
VCO[3:0] VCO_CURRENT_B[3:0] 8 -
Recommended setting: VCO_CURRENT_A=4
Control of current in VCO core for frequency B
The current steps are the same as
for
VCO_CURRENT_A
Recommended setting: VCO_CURRENT_B=4
SWRS045B Page 70 of 89