![]() The ATmega328p datasheet shows that the minimum voltage of a logic high at a pin is 90% of Vcc. It’s unlikely that the Arduino itself will draw 200mA, but let’s assume that between the Arduino and the other devices connected to it, they draw a total of 200mA. The maximum current draw of the Arduino is 200mA. (Source: Example: Arduino Pro Miniįirst, let’s assume a circuit design that uses something like the Arduino Pro Mini. However, the same principles apply to 5 Vdc devices. The examples provided below refer to 3.3 Vdc devices where the power source considerations are more critical. (Vcc is the regulated DC supply voltage needed to operate an IC and is often referred to as a supply voltage for ICs.) Most commonly, Arduinos are designed to work at either a 3.3 V level logic for low power consumption or 5 V logic to be compatible with legacy TTL logic devices. Microchip’s ATmega328 has a wide range of acceptable Vcc voltages. Many Arduinos use the ATmega328P microcontroller. It’s not as simple as saying that a 5V Arduino uses a 5Vdc power supply and a 3.3V Arduino uses a 3.3 Vdc power supply. The Arduino family of development boards provides solutions for these problems, but it’s easy to get it wrong without a good understanding of what options are available when you’re designing it. While concentrated effort and forethought may be in the details of the design itself, many performance and reliability problems can be traced back to the selection and connectivity of the power source. Selecting an appropriate power source for microcontroller-based designs is often overlooked. I’ve seen veteran engineers baffled as to the reasoning behind powering a 3.3V Arduino with a 9Vdc power supply until it’s been explained to them. Some Arduinos accept 6Vdc to 16 Vdc of input voltage, which is well above the maximum rating of the MCU, but the Arduino board regulates the supply voltage accurately as well as additional power for Arduino peripherals. Taking advantage of this allows for longer power supply wiring runs by using a higher voltage power supply than the nominal 5V or 3.3V needed by the microcontroller (MCU) for logic levels. It wasn’t obvious to me when I first started working with them, but Arduinos have on-board regulation. Powering an Arduino has a little magic to it.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |