Trying to get this cheap nfc chip working under 1.8v system.
By default it speaks spi at 3v3. I constructed 1v8 3v3 level converter using txb0108 . And what I can tell with my oscilloscope it seems to be working. But still I get errors while reading/writing.
I was reading datasheet and noticed Pin #2 - PVDD pin power supply. And remembered reading reference design that said something about selectable io levels. I thought that it would be simpler and less error prone to try interface without level transformation. So I yanked mfrc522 chip out and redid some circuit pathing under it. reflowed, put 1.8v to pin #2(PVDD) 3.3v elsewhere. And the result was exactly the same.
Does somebody have more experience with datasheets and can say if my assumption to supply 1.8v to PVDD to get 1.8v level io was correct?
By default it speaks spi at 3v3. I constructed 1v8 3v3 level converter using txb0108 . And what I can tell with my oscilloscope it seems to be working. But still I get errors while reading/writing.
I was reading datasheet and noticed Pin #2 - PVDD pin power supply. And remembered reading reference design that said something about selectable io levels. I thought that it would be simpler and less error prone to try interface without level transformation. So I yanked mfrc522 chip out and redid some circuit pathing under it. reflowed, put 1.8v to pin #2(PVDD) 3.3v elsewhere. And the result was exactly the same.
Does somebody have more experience with datasheets and can say if my assumption to supply 1.8v to PVDD to get 1.8v level io was correct?