si4021 Silicon Laboratories, si4021 Datasheet - Page 20

• Manufacturer Part Number: si4021
• Description: Si4021 Universal Ism Band Fsk Transmitter
• Manufacturer: Silicon Laboratories

Note:
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•
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Data Transmit Sequence Through the FSK Pin
Data Transmit Sequence Through the SDI Pin
Do not send CLK pulses with the TX data bits, otherwise they will be interpreted as commands.
This mode is not SPI compatible, therefore it is not recommended in microcontroller mode.
If the crystal oscillator and the PLL are running, the t
nSEL
SCK
SDI
FSK
Internal operations
ex, es, ea = 1
a0, a1 = 0
P o w e r M a n a g e m e n t C o m m a n d
C 0 h
synthesizer / PLL /
Xtal osc staus
instruction
PA status
d o n ' t c a r e
3 8 h
sx
+t
sp
delay is not needed.
t
sx *
t
sp *
synthesizer on, PLL locked, PA ready to transmit
xtal osc. stable
T X D A T A
NOTE:
* See page 6 for the timing values
IA4221
20