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EVAL6470H FLAG LED lit

Question asked by choi.henry on Jun 25, 2013
Dear forum, I am trying to talk to the L6470 IC on the EVAL6470H board over SPI.  I am not getting any SPI replies from the IC, but probably the immediate problem is that as soon as the board is powered AND the SPI cable is connected to my TI C2000 Launchpad board, the FLAG LED on EVAL6470H is lit.  I read the condition for the FLAG pin driven low, and believe that none of those apply to me.  I checked Vs (16 V) and Vreg (3 V).
Q1: has the board come out of RESET?
A: It seems so, because when I drive nSTANDBY/RESET to FALSE, the LED goes dark.  When I load nSTANDBY pin again, the LED gets lit again.

Datasheet section 6.18 says these are the nFLAG pin causes:

Power-up or standby/reset exit, Stall detection on A bridge, Stall detection on B bridge , Overcurrent detection, Thermal warning, Thermal shutdown,  UVLO, Switch turn-on event, Wrong command, Non-performable command.

I don't think any of these apply to me.  Maybe I'll try grounding the SW.  Any advice please?

UPDATE: Just changed the SPI polarity to FALLING, and the FLAG went away.  I should have.  Should have remembered Sherlock Homes quote: "When you eliminate all other possibilities, what remains, no matter how improbable, is the answer."  I guess the IC was complaining about SPI all along!

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