Converting TIM/6Steps demo to external clock input

Posted on May 17, 2011 at 13:35

Hi,

Help an overwhelmed STM newbie for Christmas!

There is an old *** pre-CMSIS *** application implementing a DMA parallel port triggered off an external clock signal described in an2548.zip (in the old pre-cmsis firmware archive).

There is also a CMSIS FW project in the TIm folder, called 6Step.

Could any of you brainy folks show me code that would convert 6Step to be clocked off an external clock input (like in an2548), effectively allowing the clock to be used as variable speed counter? This is so that the generated outputs would stay synchronised with something that changes its speed of rotation on the fly.

Also, a question on interrupts in case I have to string a bunch of one-shots together instead. IF interrupts are being served 50 to 350 times per second, does that pose a problem for, for example, I2C communications? Or is it taken care of by the fact that the I2C peripheral is off core and can wait until the core gets back to it to finish feeding it code?

Thanks!

Posted on May 17, 2011 at 13:35

Anyone know or explain how to do this?

Please help!

Posted on May 17, 2011 at 13:35

Hi, you should be able to assemble the old code with the new one, creating ext. clock on 6PWM output quite simple.

What concerns interrupts, in my application they occur at rate 200.000 per second, and Cortex has no trouble solving them :)

I2C needs interrupts with highest priority, because there are some time-critical state machine actions needed! With highest priority set, 350 other interrupts/s play no role :)

Posted on May 17, 2011 at 13:35

Is what I am asking not possible?

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