LP8556SQ i2c

Terry,

Yes, all versions of LP8556 have a i2c slave function.  The LP8556 has an EPROM to store its default configuration.  Table 1 shows different ordering numbers for different default EPROM configurations.  Some configurations have the brightness control defaulted to the PWM input and some configurations for i2c brightness register.  You cannot rewrite the EPROM, so if you need to make changes to the configuration of the LP8556 it must be done every time after the EPROM is loaded following power-up.  So it is more convenient to select a device with default values to match your system architecture.  The details of the PWM and i2c brightness control method setting are below.

There is a brightness control method setting (BRT_MODE) in the device control register (addr 01h).  You can program that register (via i2c) to set whether the LED brightness is controlled by the external PWM or i2c brightness register (addr 00h).  This is a 2-bit setting and are also a few modes where the LP8556 will multiply the PWM input and i2c Brightness register (for applications where two brightness control methods are required).  The default value for the BRT_MODE setting is stored in EPROM.
 

Thanks,

Jeremy