Jakie są za i przeciw dla obu sposobów zagospodarowania wolnych portów MCU (Atmega)?
- bezpośrednio do masy
- do masy przez rezystor
- zostawić wiszące "w powietrzu"
Dariusz Żołna
- posted
15 years ago
Wolne porty do GND czy w powietrze?
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- Vote on answer
- posted
15 years ago
Takich rzeczy albo szuka się bezpośrednio w datasheecie, albo wnioskuje po konstrukcji portów (o ile jest znana i ma się trochę wiedzy).
A oto co mówi datasheet:
„If some pins are unused, it is recommended to ensure that these pins have a defined level. Even though most of the digital inputs are disabled in the deep sleep modes as described above, floating inputs should be avoided to reduce current consumption in all other modes where the digital inputs are enabled (Reset, Active mode and Idle mode).The simplest method to ensure a defined level of an unused pin, is to enable the internal pull-up. In this case, the pull-up will be disabled during reset. If low power consumption during reset is important, it is recommended to use an external pull-up or pull-down. Connecting unused pins directly to VCC or GND is not recommended, since this may cause excessive currents if the pin is accidentally configured as an output.”