RF31 Hope Microelectronics co., Ltd, RF31 Datasheet - Page 20

• Manufacturer Part Number: RF31
• Description: Rf31 Ism Receiver
• Manufacturer: Hope Microelectronics co., Ltd

Add
3.5. System Timing
The system timing for RX mode is shown in Figure 7. If a small range of frequencies is being used and the
temperature range is fairly constant a calibration may only be needed at the initial power up of the device. The
relevant system timing registers are shown below.
The VCO will automatically calibrate at every frequency change or power up. The VCO CAL may also be forced by
setting the vcocal bit. The 32.768 kHz RC oscillator is also automatically calibrated but the calibration may also be
forced. The enrcfcal will enable the RC Fine Calibration which will occur every 30 seconds. The rccal bit will force a
complete calibration of the RC oscillator which will take approximately 2 ms. The PLL T0 time is to allow for bias
settling of the VCO, the default for this should be adequate. The PLL TS time is for the settling time of the PLL,
which has a default setting of 200 μs. This setting should be adequate for most applications but may be reduced if
small frequency jumps are used. For more information on the PLL register configuration options, see ―Register
53h. PLL Tune Time,‖ and ―Register 55h. Calibration
53
54
55
R/W
R/W
R/W
R/W
Tel: [phone]
PLL Tune Time
Function/De
Reserved 1
Calibration
scription
Control
D7
X
Fax: [phone]
xtalstart
half
D6
X
Figure 7. RX Timing
pllts[4:0]
adccaldo
Control,‖.
D5
ne
X
E-mail: [e-mail]
enrcfcal
D4
X
rccal
D3
X
Vcoca
ldp
D2
X
http://www.hoperf.com
vcocal
pllt0[2:0]
D1
X
R F 3 1
skipvco
D0
X
POR
Def.
45h
00h
04h
20