Specifications
CC
1100E
SWRS
082
Page
73
of
92
0x16: MCSM2
–
Main Radio Control State
Machine C
onfiguration
Bit
Field Name
Reset
R/W
Description
7:5
R0
No
t used
4
RX_TIME_RSSI
0
R/W
Direct RX termination based on RSSI measurement (carrier sense). For
ASK/OOK modulation, RX times out if there is no carrier sense in the first 8
symbol periods.
3
RX_TIME_QUAL
0
R/W
When the
RX_TIME
timer expires, the chip ch
ecks if sync word is found
when
RX_TIME_QUAL=0
, or either sync word is found or PQI is set when
RX_TIME_QUAL=1.
RX_TIME[2:0]
7 (111)
R/W
Timeout for sync word search in RX
for both WOR mode and normal RX
operation
. The timeout is relative to the progr
ammed
EVENT0
timeout
.
2:0
The RX timeout i
n
µ
s is given by
EVENT0
·C(
RX_TIME
,
WOR_RES
)
·26/X
, where C is given by the table below
and X is
the crystal oscillator frequency in MHz:
Setting
WOR_RES = 0
W
OR_RES = 1
WOR_RES = 2
WOR_RES = 3
0 (000)
3.6058
18.0288
32.4519
46.8750
1 (001)
1.8029
9.0144
16.2260
23.4375
2 (010)
0.9014
4.5072
8.1130
11.7188
3 (011)
0.4507
2.2536
4.0565
5.8594
4 (100)
0.2254
1.1268
2.0282
2.9297
5 (101)
0.1127
0.5634
1.0141
1.4648
6 (110)
0.0563
0.2817
0.5071
0.7324
7 (111)
Until end of packet
As an example,
EVENT0
=34666
,
WOR_RES
=0
and
RX_TIME
=6
corresponds to 1.96 ms RX timeout, 1 s polling interval
and 0.195% duty cycle.
Note that
WOR_RES
should be 0 or 1 when using WOR because using
WOR_RES
> 1 will give a
very low duty cycle. In applications where WOR is not used all settings of
WOR_RES
can be used.
The du
ty cycle
using WOR
is approximated by:
Setting
WOR_RES
=
0
WOR_RES
=1
0 (000)
12.50%
1
.
95%
1 (001)
6.250%
9765ppm
2 (010)
3.125%
4883ppm
3 (011)
1.563%
2441ppm
4 (100)
0.781%
NA
5 (101)
0.391%
NA
6 (110)
0.195%
NA
7 (111)
NA
Note that the RC oscillator must be enabled in order to use setting 0
-
6, because the timeout counts RC oscillator
periods. WOR mode does not need to be enabled.
The timeout counter resolution is limited: With
RX_TIME=0
, the
timeout count is given by the 13
MSBs of
EVENT0
,
decreasing to the 7MSBs of
EVENT0
with
RX_TIME=6
.