Hello . As there is something with the board I made , I cant work it out . So I bought EVAL-ADPD188BIZ-S2 from you .

I'm trying to use it ,but I still got some questions .

As shown in the sheet (《EVAL-ADPD188BIZ-S2 User Guide》)。I connect I2C_SCL and I2C_SDA, 1.8V voltage,GND to my STM32 board. I connect MOSI SCLK

to the GND and CS to 1.8V .Then I generate I2C waveform ,the waveform is wrong . Is there anything wrong with my connections? If so ,please tell me .If not ,I will

explain more details on the waveform I got . Thanks !

Parents Reply
  • +1
    •  Analog Employees 
    on Dec 14, 2020 8:46 PM in reply to hitlhd

    So you mean you have a regulator between the microcontroller and ADPD188BI? Ideally, it shouldn't be a problem at all if your regulator works well. In fact, 1.8 V is even safer. You can connect pull-ups to 3.3 V in I2C, but you don't have to.

    By the way, did you tie sclk and mosi to the ground? I know you tied cs to 1.8 V.

  • Hi,

    After I received you reply ,I connect my 3.3V I2C signal to EVAL-ADPD188BIZ-S2 ,but It still didn't work ,I will explain it and I wonder If I can get some advice from you .

    Here is the EVAL-ADPD188BIZ-S2  board I use .I regard the part I circled with red line as the part  the second picture shows .

    As I read <<EVAL-ADPD188BIZ-S2 User Guide>> from  your website , the connection of S2 board is in | Page 7 of 11, and Here is it. (If It's wrong?)

    As I signed in the picture above , I connect S2 board with :

    Pin 1,2 to 1.8V  . Pin 7 to 3.3V I2C_SDA from STM32  , Pin 8 to 3.3V I2C_SCL from STM32. 

    Pin11(SPI_CLK) , Pin13(SPI_MOSI) and pin15,16 to GND .

    Pin12(SPI_CS) to 1.8V . And I didn't connect other pins to anything .

    Then I will introduce the waveform I get .

    First , the picture below is the I2C signal I get From STM32 .

    Then ,the picture below is the I2C signal I get when I connect STM32 to EVAL-ADPD188BIZ-S2 board .

    It's a soft I2C signal I made ,the IO state is OD .I didn't do any configuration to ADPD188BI, I'm just trying to communicate with it .

    So I read register 0x08 (00001000).The I2C slave address is 0x64 (1100100) . The rate is 100kb/s .There are no ACK signals .

    But In fact , I can communicate with  two kinds of EEPROMS including M24C02 and AT24C64.

    If there is something wrong with my Conncetion or my signal is not pure enough or maybe any reasons?

    I've been troubled for a long time . Looking forward to your advice !

  • It's OK now ! Maybe something  wrong I didn't notice  happened . Thankyou for your advice !