Hi everyone,
My doubt comes from a recommendation that someone from a MCU maker made me through support area but I dont understand the purpose. I explained the support agent that the project is battery powered (2 AA batteries) so I am very concerned about the battery duration (I dont know if this is the reason of the recommendation).
The project:
- One MCU (1.8V-3.6V work range) which inputs are activated with tact switches (10 in total)
- The inputs are activated with a high signal
- The tact switches are directly connected to the two AA batteries that supply 3V, so when they are closed they supply 3V to the MCU
- Each input connected to a tact switch has one pulldown
The support agent recommend within other advices to include a series resistor between the tact switch and the MCU input. I dont understand if this recommendation is related to consumption or to something else. The voltage supplied by the tact switch is within MCU range so the resistor purpose is not reducing the 3V.
My only idea is that I=V/R, then a resistance in series would reduce the current that input is drawing but I truly have no idea how much current would the input draw at 3V without any series resistor. What do you think?
My doubt comes from a recommendation that someone from a MCU maker made me through support area but I dont understand the purpose. I explained the support agent that the project is battery powered (2 AA batteries) so I am very concerned about the battery duration (I dont know if this is the reason of the recommendation).
The project:
- One MCU (1.8V-3.6V work range) which inputs are activated with tact switches (10 in total)
- The inputs are activated with a high signal
- The tact switches are directly connected to the two AA batteries that supply 3V, so when they are closed they supply 3V to the MCU
- Each input connected to a tact switch has one pulldown
The support agent recommend within other advices to include a series resistor between the tact switch and the MCU input. I dont understand if this recommendation is related to consumption or to something else. The voltage supplied by the tact switch is within MCU range so the resistor purpose is not reducing the 3V.
My only idea is that I=V/R, then a resistance in series would reduce the current that input is drawing but I truly have no idea how much current would the input draw at 3V without any series resistor. What do you think?