Customer:
The 9548A board is nice with the easyC buses. How do I connect the jumpers for A0, A1, A2? I would like to control them dynamically. Is this possible? Do I have to solder them?
Originally submitted via email support on 18 August 2024. Migrated to the forum for community visibility.
Soldered Support:
A0, A1 and A2 connect to the I2C expander chip directly and they set its main address. Be aware that changing this expander chip’s I2C address dynamically while a program is running may not work as intended, as it could require a reset of the chip (the pin states are read once when it’s powered on). Changing the address would also change the way you go about using it in code. The main reason to use these jumpers is to change the address if you already have an I2C device at 0x70.
You could theoretically dynamically connect and disconnect them through some circuit, but it’s not clear how this would work with that chip exactly. Check the datasheet: https://soldered.com/productdata/2022/03/Soldered_tca9548a_datasheet.pdf
From personal experience, even the datasheet can’t offer full information in cases like this, and just testing is required. If you could share your use case in more detail, that might help find a better approach.