I2C Addressing in ST25DV64KC

[Nishi]

Hello,

I'm using ST25DV64KC NFC to communicate with Raspberry Pi 4 Model 4 over 12C. I would like to access static registers from I2C, and is a bit confused on I2C addressing. Looking the data sheet of ST25DV64KC, to access GPO register (System configuration area), the I2C address should be 0x AF as per following addressing scheme.

 

Device Type :- b7-b4:- 1010 

Chip Code   :- b3|b2|b1 :- E2|E1|1 - 111, E1 is 1for System Configuration Area, 0 for others.

R/W      :- b0 :- 1 for R and 0 for W :- 1 as we are reading the register

10101111=0xAF

 

However, i2cdetect returns 53 and 57 as the i2c address as shown below

 

 i2cdetect -y 1

   0 1 2 3 4 5 6 7 8 9 a b c d e f

00:             -- -- -- -- -- -- -- --

10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

50: -- -- -- 53 -- -- -- 57 -- -- -- -- -- -- -- --

60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

 

I was expecting AF instead of 53 and 57, looks like i'm missing something here.

 

Thanks,

Nishi

 

 

 

 

[Peter BENSCH]

Welcome @Nishi, to the community!

you have been confused by the shifting of the address bits. Read this thread, for example, where @TDK has explained this.

Regards
/Peter