micrf506 Micrel Semiconductor, micrf506 Datasheet - Page 27

• Manufacturer Part Number: micrf506
• Description: 410mhz And 450mhz Ism Band Transceiver
• Manufacturer: Micrel Semiconductor

To avoid this situation, always make sure max count
is between limits. Suggestion: Count for 8 (or 16)
bits only.
Procedure description:
In the procedure below, UP+DWN pulses are
counted, and only the sign of the FEE is used. The
value of n is 8 or 16.
Assumption:
A transmitter is sending a 1010… pattern at the
correct frequency and bitrate.
The wanted receiver frequency is the mid-point
between the “0” and “1” frequencies.
Input:
Output
Local variables:
XCO TUNE PROCEDURE
INT:
LOOP:
Micrel
September 2004
Nothing
The best XCO_tune value (giving the lowest IFEEI)
XCO_Present: (5-bit) holds present value in
XCO_tune bits
XCO_Step: (4-bit) holds increment/decrement of
XCO_tune bits
SCO_Sign:
(increment/cerement) increasing LO is done by
reducing the XCO_tune value
XCO_Present = 0
XCO_Step = 32
XCO_Sign = NEG
Control_Word =
Default RX, clocks match transmitter
XCO_Step = XCO_Step/2
XCO_Sign == POS?
XCO_tune bits = CXO_Present
Program RFChip
Yes --> XCO_Present- = XCO_Step // increase LO
No --> XCO_Present+ = XCO_Step // decrease LO
(1
bit)
holds
POS
or
NEG
27
Delay > n bits
Read FEE
FEE > 0?
XCO_Step > 1?
FIN: RETURN, return-value = XCO_Present
Yes --> XCO_Sign = POS
No --> XCO_Sing = NEG // negative or == 0
Yes --> Branch to LOOP
No -->
XCO_Sing ==POS?
Branch to FIN
Yes --> XCO_Present- = 1
[phone]
M9999-092904
MICRF506