micropython/micropython — pull request #925 by dhylands (2014-10-22 17:09:23+00:00)
Title: Fixed TIM2_CH1 definition.

TIM2_CH1_ETR is really bundling 2 functions to the same pin:
TIM2_CH1 (where its used as a channel)
TIM2_ETR (where iss used as an external trigger).

I fixed most of these a while back, but it looks like I missed this one.