search

monkeyboard / Wiegand-Protocol-Library-for-Arduino

Wiegand 26 and Wiegand 34 Protocol Library for Arduino
323 stars 131 forks source link

Possible get card code reverse with command #57

Open hinkma opened 2 years ago

hinkma commented 2 years ago

Have possible give somehow direct card code reverse example 9B3FAA, AA3F9B? Need new part to software? Example wg.getCode (), HEX / wg.getCodeinv (), HEX Some reader give data reverse.

jpliew commented 2 years ago

Hey @hinkma

There are C routines that does the reversal of bits, some pointers here https://www.google.com/search?client=firefox-b-d&q=c+programming+reverse+bit+order

mrNo0b commented 1 year ago

I have the same problem... Why it reads in reverse in the first place? what might cause this issue? btw I also got 3 pairs of hex chars at first but when used NFC Tools on android to read the same tag I had 4 pairs, I have WG26/34 wire (gray) on my RFID reader so I connected it to ground and now I get full 4 pairs hex (only in reverse...) I also tried to flip the D0,D1 wires and got completely different code.

Is it possible to add bool parameter to void WIEGAND::begin(int pinD0, int pinD1) that will reverse card code?

Is it possible to read data from tag?

And I think it would be good to turn on discussions for this repository.

Edit: Found this https://www.geeksforgeeks.org/reverse-bytes-of-a-hexadecimal-number and added the macro to my code #define REV(n) ((n << 24) | (((n>>16)<<24)>>16) | (((n<<16)>>24)<<16) | (n>>24)) seems to work right, it reads the same code as NFC Tools.