L6470 Switch Input

[tborgoyn]

I am using a L6470 and everything is working fine with one exception. When I do the initialization of the step mode and configuration registers, if the SW input is low, then the initialization does not work. If the SW input is high, then everything works fine. The signal levels on the SW input are compliant with the Vdd levels (3.3V). Looking for any insight.

 

Tom

[juing]

Experiencing the same behavior. L6470 goes out of HiZ state if it detects the switch is active at powerup. The result is the INT_SPEED, ST_SLP, FN_SLP_ACC, FN_SLP_DEC registers are not writable.

Seems to be either an undocumented behavior or an actual flow in L6470 design.