pull-up when using portlevel mode

[YannickF]

Hi

I have spent a lot of time searching why my bootloader always started.
Actually, I have configured the bootloader to start when a port pin is
set to 0. So, a jumper is connected between this pin and the ground.

But there is no pull-up resistor activated in the code.... so, the pin
level isn't determined when the jumper isn't connected. (Randomly,
sometimes it's a 1, often it's a 0... and the bootloader starts even
if it's not desired)

I added a line in the source code for activating the pull-up resistor
on thispin and everything works fine now.

--
YannickF.
http://www.yannickf.net/

[shaoziyang]

Hi,

After reset, in normal condition, all io pin will be input mode with internal pull up enable.

But if you jump to bootloader from your application, io pin maybe other mode. In this case, you need add some code to make sure it will be input mode with internal pull up resistor.

--

Best regard!

Shao ziyang
Shaoz...@126.com
http://blog.ednchina.com/shaoziyang/
https://sites.google.com/site/shaoziyang/

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