1. Xử lý các chân MCU khi không được sử dụng
+ Nối vào nguồn hoặc đất qua 1 con trở, tránh tình trạng thả nổi (floating).+ Cấu hình chân đó là output hoặc input pull-up
Lý do:
When you have a not connected pin, the first thing you need is to
clamp it to a rail, either Vcc or ground. You need this because a
floating state may cause an intermediate state in the input buffers,
leading to static power absorption.
To force a level, you can either set the pin as output or input with internal pull-up. My measurements didn't show any difference in the power absorbed with the two solutions, but the manual (of a Jennic microcontroller) suggested to use the latter (input with pull-up). I'd say it's reasonable, because it uses a weaker pull-up than the output mode, and this may reduce leakage.
To force a level, you can either set the pin as output or input with internal pull-up. My measurements didn't show any difference in the power absorbed with the two solutions, but the manual (of a Jennic microcontroller) suggested to use the latter (input with pull-up). I'd say it's reasonable, because it uses a weaker pull-up than the output mode, and this may reduce leakage.
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