MRF24J40MD Datasheet, PDF (8/34 Pages) Microchip Technology – 2.4 GHz IEEE Std. 802.15.4™ RF Transceiver Module with PA/LNA

MRF24J40MD/ME
1.4.2 ENERGY DETECTION (ED)
Before performing an energy detection (see Section
3.6.1 “RSSI Firmware Request (RSSI Mode 1)” in the
“MRF24J40 Data Sheet” (DS39776), perform the
following steps:
1. Configure the internal RF state machine to normal
operation (TESTMODE (0x22F<2:0>) = 000).
2. Configure GPIO2 and GPIO1 direction for
output (TRISGP2 (0x34<2>) = 1 and TRISGP1
(0x34<1>) = 1).
3. Set GPIO2 (0x33<2>) = 1 and GPIO1
(0x32<1>) = 0. This enables the LNA and
disables the PA.
4. Perform the energy detection following the steps
in Section 3.6.1 “RSSI Firmware Request (RSSI
Mode 1)” in the “MRF24J40 Data Sheet”
(DS39776).
Note:
The LNA will amplify the received signal.
The RSSI value will include the receive
signal strength plus the LNA amplification.
1.4.3 SLEEP
To get the lowest power consumption from the
MRF24J40MD/ME module during Sleep, it is neces-
sary to disable the PA, PA voltage regulator and LNA.
To do this, perform the following steps:
1. Configure the internal RF state machine to normal
operation (TESTMODE (0x22F<2:0>) = 000).
2. Configure the GPIO2, GPIO1 and GPIO0
direction for output (TRISGP2 (0x34<2>) = 1,
TRISGP1 (0x34<1>) = 1) = 1 and TRISGP0
(0x34<0>) = 1).
3. Set GPIO2 (0x33<2>) = 0 and GPIO1
(0x32<1>) = 0. This disables the LNA and the PA.
4. Put the MRF24J40 to Sleep following the steps
in the “MRF24J40 Data Sheet” (DS39776).
When waking the module, re-enable the PA/LNA Mode.
DS70005173A-page 8
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