EVAL-L9942 interface problem

Posted on September 18, 2014 at 17:37

Hello!

I bought 3 Eval-L9942 boards. I connected supply voltage (5V). Enable (connect to 5V) and a step clock (5V. 100Hz). The VS supply is 12V.

The motor i have connected does not move. All outputs are at 12V constantly.

I have connected a SPI interface (Aardvark) and read out the phase count register (it counts up).

Have I missed something? I have no clue why the driver is not working.

By the way, is it possible to read out the phase counter or change the motor direction without overwriting the phase counter?

best regards

Philipp

Electronics Design Engineer

#motor-driver #l9942 #eval-l9942

This topic has been closed for replies.

ST Employee

Posted on September 22, 2014 at 08:51

Dear Philipp,

Did you program the registers (see chapter 5) ? Did you program the current profile table (registerS 2Ã·6)?

Check the SPI setting: The SPI peripheral works in mode CPOL = 0 and CPHA = 0. Check chapter 4 and paragraph 6.6 (SPI Timing).

Best regards,

Marco

Associate

Posted on September 22, 2014 at 15:30

Dear Marco,

as I did understand the datasheet, I dont need to programm Registerns 2-6.

The L9942 will run in its initial conditions which are 95mA micro step,

When I apply a step clock a small currnent shall run into the motor but instead of that all outputs stay at motor supply voltage.

best regards

Philipp

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