RFD21737 Evaluation Board
CCS C Compiler
SCREENSHOT 3. This ESN data was obtained by manually invoking the
ESN read-back function.
Lemos International Co., Inc.
RF Digital RFD21737
RF Digital RFD21733
CCS C compiler. It’s called SIOW. After placing the receiver
in Serial Transceiver mode and the transmitter in RFID
mode, I fired up both RFD21733s.
Well, looky here. We have captured some data in
Screenshot 1. The first byte is exactly what we expected
and identifies the packet as an RFID packet. The remaining
four bytes should be the transmitter’s ESN.
There is a way we can verify the received ESN. The
RFD21733 can be forced to dump its ESN in ASCII format
using the ESN read-back procedure. All we have to do is
enter a UART mode (preferably Mode 2), tie the
RFD21733’s LEARN pin logically high, and hold the RESET
pin logically low. Since we’re doing this without a
microcontroller, we will call upon SIOW to send the ASCII
text “READ ESN” to the RFD21733 as soon as we release
its RESET line. As you can see in Screenshot 2, I’ve
primed the SIOW ESN read-back terminal session. As soon
as I manually disconnect the RESET pin from ground, I’ll
SCHEMATIC 2. The RFD21733 is very easy to
interface to a PIC. Almost every one of the
PIC on-chip resources are available to the
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