7/30/2023 0 Comments Arduino pro mini 5v outputInt getBandgap(void) // Returns actual value of Vcc (x 100)Ĭonst long InternalReferenceVoltage = 1059L // Adjust this value to your boards specific internal BG voltage x1000 Int battVolts // made global for wider avaliblity throughout a sketch if needed, example a low voltage alarm, etcīattVolts=getBandgap() //Determins what actual Vcc is, (X 100), based on known bandgap voltage Thanks to "Coding Badly" for direct register control for A/D mux Now works for 168/328 and mega boards. This demonstrates ability to read processors Vcc voltage and the ability to maintain A/D calibration with changing Vcc Function created to obtain chip's actual Vcc voltage value, using internal bandgap reference The bandgap waries a bit from chip to chip, so the sketch provides for a way to calibrate for a particular chip. The ADMUX register is described in detail in Section 24.9.1 in the datasheet for the 328P. It should work for the 328P in the Pro Mini. I don't know of a library that includes this option, but below is an example sketch that produces the value of the Vcc voltage based on the bandgap reading. The ADMUX register selects the reference for the measurement, which will be Vcc, and channel of what is being measured - that will be channel 14, the internal 1.1V bandgap voltage. A P channel to shut off the divider at the high side and an N-channel to control the P channel. To disconnect the input divider you will need two mosfets.For power savings look into the processor sleep modes.This will reduce the noise getting into the A/D conversion. You should put a 0.1µ Capacitor between the analog input pin and a ground pin nearby. If you Must go to 4Mhz then you will have to load a new bootloader capable of operating at 4 Mhz. I can't say if you will have issues operating your board a the 2.5V of the battery low voltage. The ATmega will operate down to ~ 2 volts, however the lower the voltage goes, the lower the clock frequency it will operate at. I would simply crush the parts to be removed with a needle nose pliers. If you decide to remove the regulator you can still easily program the board by powering it with your battery and disconnecting power coming from your programmer. However you must not put a load on the Vcc pin (essentially the input of the regulator. I will also have to study how to power down with interrupts to save energy.Īll the low voltage drop regulators I've ever found on my Arduino's will withstand voltage on the output. With no switch if the LED stays on it will "drain" the battery - same they say for the regulator (in reverse? prevented by a diode?).
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