Dead time accessed when?

marbel · ‎2013-09-25

Posted on September 25, 2013 at 09:07

Hi

I need to be able to adjust the dead time of one of the advanced timers in an F4 during execution.

I can easily write to the BDTR register but it seems a bit dangerous to do so without knowing when the timer will use the content of the register in order to control the outputs.

Anybody knows when this is done or perhaps if the register is shadowed during update event or something like that?

// Martin

#advanced-timers #timer-dead-time-tim1-bdtr

jpeacock2399 · ‎2013-09-25

Posted on September 25, 2013 at 15:53

Dead time is used when the timer outputs are commutated, typically driving 2 or 3 H bridges of power transistors for motor phases. Since the outptus change on the commtate event (for advanced timers TIM1 and TIM8) your dead time needs to be stable before then. The purpose of the dead time is to prevent shoot-thru (H bridge short) due to latency in switching the transistors.

Dead time is usually a function of the switching time of the H bridge so it doesn't change once it's been set. Are you doing something different?

Jack Peacock