I2C Sniffer

[chipfryer27]

Hi

Ages ago Medelec35 created a very useful I2C address "sniffer" which has now made its way to the WiKi / Examples. A very useful little device it is too. Today, trying to get a lolin-lite talking to a new I2C LCD display that uses an I2C backback, I was getting nowhere fast. I had remapped SDA/SCL so of course being an ESP that too might have been causing issue.

Using the "sniffer" I had every address returned. Not good as this means no communications for whatever reason. However it didn't take too long to discover that if I used Software instead of Channel in the I2C Master, then the sniffer could detect my backpack at the correct address 0x27[39].

Setting my test chart, which only looped flashing the word "TEST" I had high hopes using the address. Nothing......... Changed to Software mode.... Nothing..... Still going nowhere fast (which according to Jim Steinman is how you should be going nowhere).

Investigation continued, and I'm not saying how long for, but it is sometimes helpful to turn the display contrast away from "minimum".........

Display works in Software mode and Channel.

Regards

[RGV250]

Hi,

a very useful I2C address "sniffer" which has now made its way to the WiKi / Examples

Can you post the link to it, I have just looked and cannot find it.

Regards,
Bob

[chipfryer27]

Hi Bob

Only in my phone just now, but if you go to the I2c wiki page for the i2c component you will find about half way down a link for the "sniffer" although no longer called that now. Its something like address scanner

Regards

[Steve-Matrix]

I think it's on this page:
https://www.flowcode.co.uk/wiki/index.p ... Interface)

[medelec35]

If you are interested, I can create an updated version that works with transactions.
That means I2C don't need to be in Software mode for ESP32 and other targets that will only work with transactions.
It will also work with AVI and PIC.