source for TIMx UEV

[dibs]

Posted on October 28, 2013 at 22:49

STM32F407xx

What are the sources for a TIMx update event?My specific use case is that I am using TIM3 to generate a quadrature encoder output (CC1 and CC2). See the earlier discussion on how to do this: (quadrature output - STM32F407).  I am using an internal trigger to clock TIM1. TIM1 is set up to output a PWM signal based upon its input clock (TIM3). When I set CC1 as the trigger source, the output frequency from TIM1 is what I expect, but when I use the Update Event, it is doubled. This leads me to believe that I am either doing it wrong, and/or more than just the CNT=ARR generates an UEV.Any thoughts? #timer #stm32f4 #uev

[Tesla DeLorean]

Posted on October 29, 2013 at 00:13

[DEAD LINK /public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/quadrature%20output%20-%20STM32F407&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B&currentviews=115]quadrature output - STM32F407 - cite

Well the toggle mode runs at 2x the frequency, is that what you mean? That's what allows the relative phase shift.

[waclawek.jan]

Posted on October 29, 2013 at 09:31

It's a rising edge of the trigger which advances the slave timer. If the master's CC mode is toggle, it generates a rising edge only once per two periods of the master timer; whereas the update is a *pulse* one timer cycle long, generated at each overflow of the timer, it means a rising edge at every period of the master timer.

JW

[dibs]

Posted on October 31, 2013 at 03:25

Thanks Jan,

Your answer makes sense based upon what I was seeing. Have you seen documentation that says this?