6 Replies Latest reply on Jul 28, 2019 8:58 PM by LinglingG_46

    EZI2C  Voltage Level

    yaxi_1543386

      Hi Sir ,

              My customer now have a problem about  EZI2C  voltage level.  The slave board is 5V  ,using CY8C4025AZI-S413, but the main board is 3.3,the pull-up  resistor to 3.3V ,they communicate in I2C .

              Because the pins are set to open drain , I think the  communication could work well , is that right?

              Thanks.

        • 1. Re: EZI2C  Voltage Level
          LinglingG_46

          Hi ,

           

          I2C 时钟和数据线上拉到3.3v,则需要把从机(PSoC4000s)的芯片I2C的两根线配置成TTL电平,不然VDD为5v的供电,CMOS电平高电平检测不到3.3v的高电平。

           

          推荐接法: 上拉电阻接10k,拉到5v。

           

          另外,我想确认的是: 主从是否为同时上电,会存在上电时间差吗?

           

          Thanks,

          Lingling

          • 2. Re: EZI2C  Voltage Level
            yaxi_1543386

            Hi Lingling,

                 请问下,这个电平在哪里配置?

                  同一套电源供电,不存在时间差。

                 Thanks.

                  

             

             

            Best Regards

            Yang Xiaoping(杨晓平)

             

            HING LOON DEVELOPMENT COMPANY LIMITED.

            青岛办事处

            青岛市市北区福北小区22号楼3单元301室

            TEL:18661878153     0532-85987713

            FAX:0532-85987713

            e-mail:xiaopingyang@jing-xi.com

            Website:http://www.jing-xi.com

             

            发件人: LinglingG_46

            发送时间: 2019-07-25 12:02

            收件人: yang xiaoping

            主题: Re:  - EZI2C  Voltage Level

            Cypress Developer Community

            EZI2C  Voltage Level

            reply from LinglingG_46 in PSoC 4 MCU Community - View the full discussion

             

             

            Hi ,

             

            I2C 时钟和数据线上拉到3.3v,则需要把从机(PSoC4000s)的芯片I2C的两根线配置成TTL电平,不然VDD为5v的供电,CMOS电平高电平检测不到3.3v的高电平。

             

            推荐接法: 上拉电阻接10k,拉到5v。

             

            另外,我想确认的是: 主从是否为同时上电,会存在上电时间差吗?

             

            Thanks,

            Lingling

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            • 3. Re: EZI2C  Voltage Level
              yaxi_1543386

              Hi  Lingling

                   总线 电平是否是这样设置。双击 EZI2C的组件,在EZI2C Pins 点击右键,默认值是3.3V,可更改成3.3V或5V。

                   Thanks.

              • 4. Re: EZI2C  Voltage Level
                LinglingG_46

                Hi Xiaoping,

                 

                1; I2C bus voltage 这个功能只是在部分芯片上面可以用,具体的可以查看组件datasheet,你在这里提到的psoc4000s不能用。

                2; 你可以在EZ_I2C 里面,i2c bus voltage 这个界面,选择 show EZI2C terminals, 然后自己拖两个双向的数字pin。 点击pin的组件,然后在input标签下面选择LVTTL。

                 

                具体关于这个CMOS还是LVTTL,请查看你拖的pin的datasheet。(Vh,VL为固定的值)

                 

                Thanks,

                Lingling

                • 5. Re: EZI2C  Voltage Level
                  yaxi_1543386

                  Hi Lingling,

                      我将芯片变更为CY8C4126AZI-S433 ,附件是配置,是否是这样的配置?

                      我再将上拉电阻接到3.3V上,就可以了吧。 !

                  • 6. Re: EZI2C  Voltage Level
                    LinglingG_46

                    Hi,

                     

                    是的。