Hi,
I am currently designing a product which will require I2C to be configured in a star configuration and could use some advice on the best approach.
The product is for LED lighting and will have one micro-controller in the center, with 3 to 5 smaller boards using the TLC59116 LED driver distributed around. The TLC59116 boards could be up to 1.5m from the micro-controller board, but will all run off in different directions hence the need for a 'star' rather than the standard bus. The I2C will be operating at 400kHz. Currently both the micro-controller and TLC59116 will be operating at 3.3V, but 12V will also be on both board for supply and LED drive respectively. 5V may also be available.
Communications will generally be master->slave, but the master will quite likely need to broadcast to all slaves simultaneously as part of the LED PWM level changing.
There seem to be several different options I have come across so far:
- Use a single PCA9518 five channel hub on the main board.
- Use multiple single buffers with one at each end.
- Use multiple level shifting buffers such as (to say 12V) with one at each end.
I'm not sure how noisy the environment is at the moment, but is level translation recommended? Unfortunately I don't yet have a specification for the cable, but it may be shielded.
Thanks very much for any advice.
Bernard.