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LP8556: LP8556 resets control registers to EPROM values, Flags Short and OVP in Status register 0x02

John Huebner
Prodigy 10 points
Part Number: LP8556

Tool/software:

My board seems to be worksing fine.  I've got 2 LP8556SQ-E08/NOPB devices operating under I2C control that are driving my display's backlight.

But, when I send my list of configs over I2C, status register 0x02 reads back 0x78 (short, and OVP asserted), these flags stay asserted with multiple reads.  Register 00 gets set to 0x01.  

If I write a significant number to 0x00 ie FF, backlight comes on.  A read of 0x02 shows no short flag (0x38).  A 2nd read of 0x02 clears the OVP flag.  I'm then able to then go through and configure all (one register at a time) and functionality is fine.  

Sending the full list by uC results in the same 0x78 from the status. 

I know I don't have a short...all strings are getting the right current once I go through the manual process to configure.

Any ideas??

Thanks,

John Huebner