Hello,
We have a PCB based on your older LP5569 evaluation board. (4 LP5569 drivers connected to 12 RGB LED chips). Instead of the microcontroller we are using an FT232HL USB to I2C IC connected to a computer. We are trying to work out the programming but have noticed the following behavior:
The flashing and breathing patterns use the exact same program code on each chip. I can load each chip individually, and then set the engines to free run mode simultaneously using the broadcast slave address of 0x40 to which all chips respond. But, although I can trigger the execution on all chips simultaneously, and that they visually appear to ramp up at the same rate with visual fidelity, initially, I’m observing that the ramp down times begin to drift across the chips over time and become unsynchronized rather quickly. I’ve read the datasheets for multiple TI LED drivers and, while some have more detail than others, there is no mention of non-deterministic ramp down behavior.
The programming/execution steps:
- Addressing each chip individually (0x32…0x35):
- set engine registers to SRAM programming mode
- download same program code
- Addressing all chips using broadcast address (0x40):
- set all engines to free run mode simultaneously to begin program execution
Please let me know if something seems amiss.
Kind regards,
Jack
