CC2500 Datasheet, PDF (62/76 Pages) Texas Instruments – Single Chip Low Cost Low Power RF Transceiver

CC2500
Bit Field Name
7 Reserved
6:4 DEVIATION_E[2:0]
3 Reserved
2:0 DEVIATION_M[2:0]
0x15: DEVIATN – Modem deviation setting
Reset
R/W Description
4 (100)
7 (111)
R0
R/W Deviation exponent
R0
R/W When MSK modulation is enabled:
Sets fraction of symbol period used for phase change.
When FSK modulation is enabled:
Deviation mantissa, interpreted as a 4-bit value with MSB implicit
1. The resulting FSK deviation is given by:
f_dev =
f _xosc
2¹⁷
⋅ (8 +
DEVIATION
_
M
) ⋅ 2^{DEVIATION _ E}
The default values give ±47.607 kHz deviation, assuming 26.0
MHz crystal frequency.
0x16: MCSM2 – Main Radio Control State Machine configuration
Bit Field Name
Reset R/W Description
7:5 Reserved
4
RX_TIME_RSSI
3
RX_TIME_QUAL
2:0 RX_TIME[2:0]
0
0
7 (111)
R0
R/W
R/W
R/W
Reserved
Direct RX termination based on RSSI measurement (carrier
sense). For OOK modulation, RX times out if there is no
carrier sense in the first 8 symbol periods.
When the RX_TIME timer expires the chip stays in RX mode if
sync word is found when RX_TIME_QUAL=0, or either sync
word is found or PQT is set when RX_TIME_QUAL=1.
Timeout for sync word search in RX. The timeout is relative to
the programmed EVENT0 timeout, which means that the duty
cycle can be set in wake-on-radio (WOR) mode. The RX
timeout is scaled by 1 bit less than the EVENT0 timeout with
respect to the WORCTRL.WOR_RES setting, as very long
timeouts probably also will use very low RX duty cycles.
Setting
0 (000)
1 (001)
2 (010)
3 (011)
4 (100)
5 (101)
6 (110)
7 (111)
RX timeout
T_EVENT0 / 2^(3+WOR_RES)
T_EVENT0 / 2^(4+WOR_RES)
T_EVENT0 / 2^(5+WOR_RES)
T_EVENT0 / 2^(6+WOR_RES)
T_EVENT0 / 2^(7+WOR_RES)
T_EVENT0 / 2^(8+WOR_RES)
T_EVENT0 / 2^(9+WOR_RES)
Until end of packet
Duty cycle, WOR
12.5% / 2^WOR_RES
6.25% / 2^WOR_RES
3.125% / 2^WOR_RES
1.563% / 2^WOR_RES
0.781% / 2^WOR_RES
0.391% / 2^WOR_RES
0.195% / 2^WOR_RES
N/A (no timeout)
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 7 MSBs of EVENT0 with RX_TIME=6.
Preliminary Data Sheet (rev.1.1.) SWRS040
Page 62 of 77