CC1110Fx / CC1111Fx
; Tranmit the following data: 0x02, 0x12, 0x34
; (Assume that the radio has already been configured, the high speed
; crystal oscillator is selected as system clock, and CLKCON.CLKSPD=000)
MOV
JNB
CLR
MOV
JNB
CLR
MOV
JNB
CLR
MOV
RFST,#03H
RFTXRXIF,C1
RFTXRXIF
RFD,#02H
RFTXRXIF,C2
RFTXRXIF
RFD,#12H
RFTXRXIF,C3
RFTXRXIF
; Start TX with STX command strobe
; Wait for interrupt flag telling radio is
; ready to accept data, then write first
; data byte to radio (packet length = 2)
; Wait for radio
;
; Send first byte in payload
; Wait for radio
C1:
C2:
C3:
;
RFD,#34H
; Send second byte in payload
; Done
Figure 48: Simple RF Transmit Example
14.5 Data Rate Programming
The data rate used when transmitting, or the
data rate expected in receive is programmed
Min Data
Rate
[kBaud]
Typical Data
Rate
[kBaud]
Max Data
Rate
[kBaud]
Data rate
Step Size
[kBaud]
by
the
MDMCFG3.DRATE_M
and
the
MDMCFG4.DRATE_E configuration registers.
The data rate is given by the formula below.
0.8
3.17
6.35
12.7
25.4
50.8
101.6
203.1
406.3
1.2 / 2.4
4.8
3.17
6.35
12.7
25.4
50.8
101.6
203.1
406.3
500
0.0062
0.0124
0.0248
0.0496
0.0992
0.1984
0.3967
0.7935
1.5869
256 + DRATE _ M
⋅2DRATE _ E
)
9.6
(
RDATA
=
⋅ fref
228
19.6
38.4
76.8
153.6
250
The following approach can be used to find
suitable values for a given data rate:
RDATA ⋅220
⎢
⎥
⎥
⎛
⎜
⎜
⎝
⎞
⎟
⎟
⎠
DRATE _ E = log
⎢
2
fref
⎢
⎣
⎥
⎦
500
RDATA ⋅228
DRATE _ M =
− 256
Table 62: Data Rate Step Size
fref ⋅ 2DRATE _ E
See section 13.1.5.2 on page 81 for limitations
in data rate when using other system clock
speeds than the default.
If DRATE_M is rounded to the nearest integer
and becomes 256, increment DRATE_E and
use DRATE_M=0.
The datarate can be set from 1.2 kBaud to 500
kBaud with the minimum step size as found in
Table 62.
14.6 Receiver Channel Filter Bandwidth
In order to meet different channel width
requirements, the receiver channel filter is
programmable. The MDMCFG4.CHANBW_E and
MDMCFG4.CHANBW_M configuration registers
control the receiver channel filter bandwidth.
The following formula gives the relation
between the register settings and the channel
filter bandwidth:
fref
BWchannel
=
8⋅(4 + CHANBW_ M )·2CHANBW_ E
For best performance, the channel filter
bandwidth should be selected so that the
signal bandwidth occupies at most 80% of the
channel filter bandwidth. The channel centre
tolerance due to crystal accuracy should also
be subtracted from the signal bandwidth. The
following example illustrates this:
SWRS033E
Page 190 of 239
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