Dear all,
I am currently using the NTAG I²C plus in some setup with an LPC810 and an I²C ADC.
At the beginning everything worked relatively well, but now I cannot "address" the NTAG via I²C. I had already had the problem with the changed I²C address and solved it successfully (I found it with address 0x2A and reset it to 0x55).
I actually use two "selfmade" test boards and have somehow either misadjusted or "destroyed" the chip on both. I can no longer communicate with the chips via I²C. NFC communication still works on one board, but not on the other.
I use an external voltage source (3V3) to test and program the microcontroller. However, since I ultimately want to operate the setup only via NFC, I have connected the VOUT and VCC pins. Can this lead to problems if I use both, external power supply and read out the chip via NFC at the same time?
I have already scanned through all the I²C addresses to see if they could be wrong again. Unfortunately I don't get an answer for any address (except 0x00 and 0x48 which is from another device on the bus).
I have read out the chip with a working NFC interface. The config registers (0E8 and 0E9) are set to [0x01, 0x00, 0xF8, 0x48] and [0x08, 0x01, 0x00, --]. Which should be OK according to my interpretation.
I also tried to reset the NTAG (the I2C interface) via a "repeated start condition" without a stop condition in between. But I am not sure if I have interpreted the instructions from the data sheet correctly. A picture of the I²C communication is below.
My questions in brief:
- Did I do the reset of the I²C interface correctly?
- Is there anything else I can try to reset the NTAG?
- Could I have changed something in Config, that is causing the NTAG to stop working?
- Could it be that I have somehow "destroyed" the chips or the I2C interface because I am using an external voltage source and the harvesting function at the same time?
Repeated start on I²C:
