13 FSK Operation

The Bill of Materials tables describe the components needed for ASK operation for 433.92 MHz and 315 MHz.

The following table lists the component values that change between ASK and FSK operation.

Note: The use of a high FSK data rate may excite parasitic resonant modes with some crystal types. Recommended crystals from the Bill of Materials tables hold good for both ASK and FSK.

Table 13-1. ASK and FSK Settings
ModeR1R2R5R6JPR1JPR2C8
ASKNP100 kΩ0ΩNP0ΩNPNP
FSK0ΩNPNP100 kΩNP0Ω

3.3 pF(1)

10 pF(2)

Note:
  1. C8 = 3.3 pF for 1 kHz using HC49/U or HC49US type crystals.
  2. C8 = 10 pF for 10 kHz using HC49/U, (high profile) only.
Table 13-2. Enable Control (Shutdown)
R3R4
Constant ON0ΩNP
External Standby ControlNP100 kΩ