fix examples: decoding card id

[s-light]

some more research and testing needed..

resources:

• https://mschoeffler.com/2018/01/05/arduino-tutorial-how-to-use-the-rdm630-rdm6300-rfid-reader/
• https://electropeak.com/learn/interfacing-rdm6300-125khz-rfid-reader-module-with-arduino/ (based above link)

https://wiki.seeedstudio.com/Grove-125KHz_RFID_Reader/#faqs

Q1: How to convert the output to Card Number?
A1: Please follow below steps.
Take ID: 0009776930 for example:
Card Number ID: 0009776930 ------- Decimalism [Start Bit(00) + Card Number(8 numbers)]
Output: 0700952F229F ------------- Hex [[Start Bit(07h) + Card Number(8 numbers) + Checksum]
The calculator for decimal and hex numbers is available online.

https://github.com/SeeedDocument/125Khz_RFID_module-UART/blob/master/res/RDM630-Spec.pdf

TTL Interface RS232 Data output format

1. 9600bps,N,8,1
2. CHECKSUM: card 10byte DATA entire do XOR operation
   Example: card number: 62E3086CED
   Output data:36H、32H、45H、33H、30H、38H、36H、43H、45H、44H
   CHECKSUM: (62H) XOR (E3H) XOR (08H) XOR (6CH) XOR (EDH)=08H

start	Data Characters	Checksum	end
02	10 ASCII	xxH	03