APGRD001 Microchip Technology, APGRD001 Datasheet - Page 8

• Manufacturer Part Number: APGRD001
• Description: REF DESIGN PKE PIC16F639
• Manufacturer: Microchip Technology
• Type: PKE, RKEr

Specifications of APGRD001

• Frequency: 125kHz
• Processor To Be Evaluated: PIC16F639
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: PIC16F639, PIC16F636, PIC18F2680
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

AN1024
LOW-FREQUENCY SIGNAL
DETECTION ALGORITHM AND
DETECTOR OUTPUT
Figure 8 shows the flow chart of the input signal detec-
tion with the wake-up filter enabled.
The MCU firmware, PIC16F639_Basestation.asm, is
available for download from Microchip’s web site,
www.microchip.com (see Appendix A: “Source
Code”).
FIGURE 8:
DS01024B-page 8
= Controlled by MCU
Firmware
PIC16F639 SIGNAL DETECTION FLOW CHART
(while AFE detects input signals)
Detected Output on LFDATA Pin
(LFDATA output wakes up MCU)
No
No
Set Input Channel Receiving
Set AGC Active Status bit
Status bit (CH X, Y or Z)
Configuration Registers
LF Talk-back or RF Link
MCU Programs AFE
Meets Wake-up Filter
MCU in Sleep Mode
Send Response via
Disappeared for
Input Signal in?
Requirements?
Wake-up Filter
(if AGC is on)
Correct Data?
Input Signal
Input Signal
> 16 ms?
Enabled?
Start
Yes
Yes
Yes
No
Yes
Yes
No
No
Examples of the schematics for the PKE transponder
and the base station are shown in Appendix B:
“Transponder”, Figure B-1, Figure C-1 and Figure C-2
respectively. These schematics were developed for
customer
transponder. Users can use the circuits as references
when they develop their own systems. Users can also
refer to the PKE reference demonstration kit
(P/N: APGRD001), which is available from Microchip.
Set ALERT Output Pin Low
Set Alarm Status Bit High
(If ALRTIND Bit is Set)
Soft Reset
Input Signal Continues
training
for > 32 ms?
Incorrect
Yes
purposes
© 2007 Microchip Technology Inc.
No
of
the
PIC16F639