RFM69W Datasheet, PDF (75/78 Pages) List of Unclassifed Manufacturers – ISM TRANSCEIVER MODULE

ADVANCED COMMUNICATIONS & SENSING
RFM69W
DATASHEET
7. Application Information
7.1. Crystal Resonator Specification
Table 31 shows the crystal resonator specification for the crystal reference oscillator circuit of the RFM69W. This
specification covers the full range of operation of the RFM69W and is employed in the reference design.
Table 31 Crystal Specification
Symbol Description
Conditions
Min
Typ
Max Unit
FXOSC XTAL Frequency
26
RS
XTAL Serial Resistance
-
C0
XTAL Shunt Capacitance
-
CLOAD External Foot Capacitance On each pin XTA and XTB
8
-
32 MHz
30
140 ohms
2.8
7
pF
16
22 pF
Notes - the initial frequency tolerance, temperature stability and ageing performance should be chosen in accordance
with the target operating temperature range and the receiver bandwidth selected.
- the loading capacitance should be applied externally, and adapted to the actual Cload specification of the XTAL.
- A minimum XTAL frequency of 28 MHz is required to cover the 863-870 MHz band, 29 MHz for the 902-928 MHz
band
7.2. Reset of the Module
A power-on reset of the RFM69W is triggered at power up. Additionally, a manual reset can be issued by controlling pin
RESET.
7.2.1. POR
If the application requires the disconnection of VDD from the RFM69W, despite of the extremely low Sleep Mode current,
the user should wait for 10 ms from of the end of the POR cycle before commencing communications over the SPI bus. Pin
6 (Reset) should be left floating during the POR sequence.
VDD
Reset Pin
(output)
Undefined
Wait for Module is ready
10 ms from this point on
Figure 39. POR Timing Diagram
Please note that any CLKOUT activity can also be used to detect that the module is ready.
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