mc68hc908qf4 Freescale Semiconductor, Inc, mc68hc908qf4 Datasheet - Page 104

• Manufacturer Part Number: mc68hc908qf4
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

PLL Tuned UHF Transmitter Module
12.5 Modulation
12.6 Microcontroller Interfaces
Data Sheet
104
If a low-logic level is applied on pin MODE, then the on/off keying (OOK)
modulation is selected. This modulation is performed by switching on/off the RF
output stage. The logic level applied on pin DATA controls the output stage state:
If a high-logic level is applied on pin MODE, then frequency shift keying (FSK)
modulation is selected. This modulation is achieved by modulating the frequency
of the reference oscillator. This frequency change is performed by switching the
external crystal load capacitor. The logic level applied on pin DATA controls the
internal switch connected to pin CFSK:
In case of
This crystal pulling solution implies that the RF output frequency deviation equals
the crystal frequency deviation multipled by the PLL divider ratio (see
Four digital input pins (ENABLE, DATA, BAND, and MODE) enable the circuit to
be controlled by a microcontroller. It is recommended to configure the band
frequency and the modulation type before enabling the circuit. In a typical
application the input pins BAND and MODE are hardwired.
One digital output (DATACLK) provides the microcontroller a reference frequency
for data clocking. This frequency is equal to the crystal oscillator frequency divided
by 64 (see
DATA = 0 → output stage off
DATA = 1 → output stage on
DATA = 0 → switch off
DATA = 1 → switch on
DATA = 0 leads to the high value of the carrier frequency
DATA = 1 leads to the low value of the carrier frequency
Freescale Semiconductor, Inc.
For More Information On This Product,
Figure
Table
PLL Tuned UHF Transmitter Module
Crystal Oscillator Frequency
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12-2).
12-6, where the two capacitors C6 and C9 are in series:
versus Crystal Oscillator Frequency
Table 12-2. DATACLK Frequency
(MHz)
13.56
9.84
DATACLK Frequency
(kHz)
212
154
MC68HC908QF4 — Rev. 1.0
Table
MOTOROLA
12-1).