MRF39RA Datasheet, PDF (44/72 Pages) Microchip Technology – Low-Power, Integrated UHF Receiver

MRF39RA
TABLE 5-2:
Name
(Address)
RegFrfMsb
(0x07)
RegFrfMid
(0x08)
RegFrfLsb
(0x09)
RegOsc1
(0x0A)
RegAfcCtrl
(0x0B)
RegLowBat
(0x0C)
COMMON CONFIGURATION REGISTERS (CONTINUED)
Bits
Variable Name
Mode
Default
Value
Description
7-0 Frf(23:16)
rw 0XE4 MSB of the RF local oscillator
7-0 Frf(15:8)
7-0 Frf(7:0)
7 RcCalStart
6 RcCalDone
5-0 —
7-6 —
5 AfcLowBetaOn
4-0 —
7-5 —
4 LowBatMonitor
3 LowBatOn
2-0 LowBatTrim
rw 0XC0 Middle byte of the RF local oscillator
LSB of the RF local oscillator
rw 0x00
Frf = Fstep  Frf23;0
Default value: Frf = 915 MHz (32 MHz XO)
Triggers the calibration of the RC oscillator when set.
w
0 Always reads ‘0’. RC calibration must be triggered in
Standby mode.
r
1
0  RC calibration in progress
1  RC calibration is over
r 000001 Unused
r
00 Unused
Improved AFC routine for signals with modulation
index lower than 2, see Section 2.4.17 “Optimized
rw
0 Setup for Low Modulation Index Systems”.
0  Standard AFC routine
1  Improved AFC routine
r 00000 Unused
r
000 Unused
rw
—
Real-time (not latched) output of the low battery
detector, when enabled.
Low Battery detector enable signal
rw
0 0  LowBat OFF
1  LowBat ON
Trimming of the LowBat threshold:
000  1.695V
010  1.835V
100  1.976V
rw
010 110  2.116V
001  1.764V
011  1.905V
101  2.045V
111  2.185V
DS40001778B-page 44
 2015 Microchip Technology Inc.