AN2818 Freescale Semiconductor / Motorola, AN2818 Datasheet - Page 14

• Manufacturer Part Number: AN2818
• Description: Romeo2 Monitor for the MC68HC908AP64 MCU
• Manufacturer: Freescale Semiconductor / Motorola

RF Message Formats
Examples
Receiving an OOK Message Without Header
Below is an example of receiving an OOK modulated message without a header. The message ID is 0x2a.
The data rate is 2400 bits per second, carrier frequency 434 MHz.
To configure system to receive an OOK data frame with ID 0x2a at 434 MHz, no header:
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1. Set CR1 register to value 0xDA using command CR1 DA <return>.
2. Set CR2 (ID register) to 0x2a using command CR2 2a <return>.
3. Set CR3 register to value 0x48 using command CR3 48 <return>.
4. Set LNA pin to logic 1 using command LNA 1 <return>.
5. Set STROBE pin to logic 1 using command STROBE 1 <return>.
6. Set AGC pin to logic 0 using command AGC 0 <return>.
7. Enable reception of messages using command RECEIVE. This sets the reset pin to logic 1, and
This configures the following bits.
CF = 1 (434 MHz carrier frequency)
MOD = 0 (OOK modulation)
SOE = 1 (strobe oscillator enabled)
SR0/1 = 10 (strobe oscillator ratio — value not important)
DME = 1 (Data Manager Enabled)
HE = 0 (No header in message)
This configures the following bits:
DR1/0 = 01 (2–2.7kBd data rate range)
MG = 0 (normal mixer gain)
MS = 0 (mixout pin set to mixer output)
PG = 1 (phase comparator gain = low gain mode)
the Romeo2 monitor will display any received data.
1 bit time
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Romeo2 Monitor for the MC68HC908AP64 MCU, Rev. 0
Figure 7. Manchester Encoding Of Data
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0
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