I actually don't have any experience with the Mifare ultralight cause I've been working exclusively with Mifare 1K cards. However, I think these cards follow the same protocol so I think you can't simply write on your card immediately. With the Mifare 1K, you have to enter an authentication first so maybe you have to do this for the ultralight as well.
I want to use the ACR122 (USB // P/N:ACR122U-A9) to write an read NFC-tags. I use Labview 2011. In your article i read that you have done such a communication. Could you send me a .vi or a project in which you have realised the communication. That would be a great help for me!!
have you got some running VI or project for reading and writing the ACR122. I have the same problem and looking for some helpful code. It would be nice if you can help me.
Here's an example of ACR122U and MIFARE Ultralight using the WinSCard.dll
made in LV2015 and exported to LV8.6, both included.
Thank you so much for posting this nidor! You saved me so much time.
I adapted your changes to my HID Omnikey 5025CL for reading HID Prox Cards and added some additional comments and log functionality.
Hope this helps someone in the future.
I am using this code and works fine. I even managed to read and write data to the EEPROM of a NFC tag.
The problem I encountered is that even though I can write data to the EEPROM, it is not readable by any other device than the ACR122U.
If I read the tag using a cell phone it is shown as empty.