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Questions tagged [microcontroller]

A device which includes a central processing unit (CPU), memory, and (generally) an assortment of I/O peripherals (UART, ADC, DAC, general-purpose I/O, I2C, etc.) in a tightly-coupled standalone package.

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51 views

Looking for a very precise tx/rx circuit module to calculate distance [closed]

Thanks for helping. I'm looking for a system that will help me find exact distance between a transmitter and receiver at a frequency of milli seconds, in distance accuracy of milli meters. I want to ...
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1answer
41 views

Optoisolator Not Switching

I’m working on a university project that involves switching a relay using an ILD213T optoisolator. The optoisolator is driven directly by an ATmega328p. I had calculated the required current limiting ...
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9answers
6k views

Using volatile in embedded C development

I have been reading some articles and Stack Exchange answers about using the volatile keyword to prevent the compiler from applying any optimizations on objects ...
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1answer
66 views

Automatic charging and power switch between USB and LiPo battery

I am designing a board which can be powered over USB and includes the use of a LiPo battery along with its charger circuit. When the USB is connected, it charges the battery as well as powers the ...
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0answers
31 views

What is the maximum supported I2C mode in the FS32K146?

In the S32K146 user-manual guide, it is mentioned as High-Speed mode is not supported by this device. (Page 1481). But in the coming section of the user-manual it is mentioned as device support HS ...
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1answer
47 views

Crystal Oscillator Power

In the following circuit: taken from: https://circuitdigest.com/tutorial/quartz-crystal-oscillator How is the crystal powered to begin oscillation? I understand the amplifier is required to prevent ...
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2answers
116 views

Can someone explain the use of the transistor in this circuit?

I came across a schematic which implemented a 1 Wire interface. However, this 1-Wire interface circuit also includes a transistor connected as shown in the picture. Can somebody expain why this has ...
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1answer
51 views

How do I interface a microcontroller to the M5480 LED driver

I am attempting to interface an Atmega328PB to an M5480 LED/Relay driver. I'm aware this part is obsolete. The reason I am trying to do this is I have an antenna tuner that uses this chip. An antenna ...
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1answer
53 views

PIC micro controller oscillator frequency

The internal clock (Q1–Q4) of PIC Micro controller runs at a quarter of the oscillator frequency (FOSC/4). My question is if i divide the frequency with 4 Then the timer period of each clock pulse ...
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1answer
36 views

Dispersing a static field from a touch circuit - escape room

I run an escape room, inside a puzzle we have is where players need to hold hands and touch 2 screws to complete a circuit and trigger a switch. I don't have the exact specs, but it's going to look ...
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1answer
24 views

ADC startup time in AT91SAM7 - what is it?

I'm working with ADC in AT91SAM7S micro-controller. Apart from parameters like ADC clock frequency prescaler and 'sample and hold time' (that I'm familiar with), there is a parameter called 'Startup ...
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1answer
28 views

Drive QVGA lcd with GPIO?

I want to drive a 2.2" QVGA LCD that has I80(Intel 8080) interface. I found that other people did it with microcontrollers that have XMEM(Atmega64) or FSMC(ST) . Now I want to know if it is ...
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0answers
27 views

MPU6050 hangs on ESP32 when operated using a battery on custom board

We are facing a very peculiar problem. We are designing a board based on ESP32 with various peripherals like motor drivers, sensors etc. We are using GPIO 4,5 on the ESP32 as I2C lines and have hooked ...
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2answers
94 views

What is the maximum slaves supported by SPI and how it is limited?

I was learning the basics of SPI-communication. It was came to following section and I was bit confused to understand the sentence. What is the meaning of " each slave in the chain will act as the ...
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1answer
145 views

Can anyone please identify this 6 pin SMD integrated circuit?

Can anyone please identify this 6 pin SMD integrated circuit or what it does? I could not find it by the code written on it. It is from a solar charger and I need to replace it.
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0answers
31 views

Preventing inadvertent feeding of an external watchdog

Most internal watchdog timers found on microcontrollers contain mechanisms to prevent an inadvertent feed, usually requiring the write of a specific key-value to the feed register, although some ...
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1answer
63 views

ATmega328p PIN reading

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2answers
63 views

Best way to monitor on/off state with a microcontroller

I have 3D printer with a cooling fan that by design is on constantly, however it only needs to be on when there is something to cool! I have no idea why they have it on all the time since it is loud ...
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3answers
205 views

Review of PCB design

In the last few months I have been working on this project and now the next stage is to make a PCB for this circuit. I know this PCB is very far from perfect (my first PCB), but I would like to know ...
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5answers
131 views

Why are devices like the MCP23008 or PCF8574 still around when cheaper alternatives exist? [closed]

INB4: if this question doesn't fit this board, please delete. But I don't know where else to ask. There're plenty of I/O port expanders available. Most of them add 8 I/O lines at the cost of two I2C ...
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2answers
51 views

GPSDO in firmware?

There are numerous designs online for hardware GPSDO (GPS-disciplined Oscillators). I'm failing to find any firmware-only implementations. I wonder if my Google foo is weak or if these are impractical ...
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1answer
85 views

I need Wifi/relay in parallel to push button

First time poster. I’m wondering if you can help. I am trying to make a dumb sauna controller (see pic) smart, so as to be able to turn on my sauna remotely. I am very much an amateur. So be kind. To ...
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1answer
37 views

Measuring 24V AC input state with microcontroller

I need to measure the state (on/off) of a 24V AC line that is currently powering a solenoid valve. The microcontroller will take over the control of the solenoid through a solid state relay, but I ...
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3answers
695 views

Building circuit to amplify small sensor signals using an Instrumentation Amplifier and 24-Bit ADC

I'm a beginner when it comes to circuit design and I have spent the last few weeks doing research on this topic. I have now chosen some ICs (Instrumentation Amplifier and ADC) and would like to build ...
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1answer
41 views

Options for debugging MCU that is freezing/crashing (AVR32)

Im currently trying to figure out why it seems like a MCU is crashing/freezing. I can recreate the crash/freezing almost everytime by doing the same procedure, and i have been looking through the code ...
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2answers
43 views

AT90CAN128 Random Malfunctions

I've got the following Situation. An AT90CAN128 connected to a LCD,multiple Buttons, Sensors,LED's and engines. Shown on the LCD are the Sensor Values and a Menu you can go through with a rotary ...
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1answer
60 views

What are the possible boot modes in the S32K146 (NXP S32K Series MCU)

I have been investigating S32K146 MCU boot modes and possible mode selection options. I am interested to know the possible boot modes and how it can be set up. From datasheet (Page -92): It can be ...
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1answer
66 views

Schematic Feedback

I am looking for design feedback regarding the following schematic. The idea is very simple. The Controller board pulls the relay coil terminal low on the relay board to activate the relay.The relay ...
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7answers
3k views

Necessity of an external watchdog timer

What is the need for an external watchdog timer for a microcontroller? Most of the microcontrollers are designed with an internal watchdog timer. However, in some of the circuits they are using an ...
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1answer
94 views

How to send data to an ESP32 with as little delay as possible from an Android app [closed]

I have an ESP32 module. I want to send data to it using an Android app. I tried using http but the delay is big especially since I want to send about 20 values per second with a delay between 50 to ...
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1answer
78 views

Measuring phase shift between current and voltage with microcontroller

I am trying to understand how this design is used to measure phase shift between current and voltage of an AC signal. From my understand there should be a PWM signal generated on the output. Resistors ...
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0answers
42 views

MAX31855 and ISO7331C isolated SPI issues

We needed isolated thermocouple readers for a work project, so I designed a PCB with two copies of the below circuit on a PCB, with the connections broken out to a JST-XH connector. I received the ...
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1answer
97 views

How can I connect two mutually exclusive output on one pin of a MCU?

I couldn't be sure how to make a proper headline, correct me if I am wrong with it. I have a reasonably working push button solution including hardware de-bouncing. There is no question on that. So,...
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0answers
48 views

Using circuit breaker instead of a fuse

I am making a contraption that uses an atmega328 to trigger a water pump to water the garden plants on a schedule. The controller will run on low power mode to sleep all day and wake up to water the ...
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2answers
58 views

relay life time [closed]

I am developing a home automation system using nodemcu esp8266. For this I want to use srd-03vdc-sl-c relay to control my appliances with nodemcu. But I am not sure that how long this system will work ...
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2answers
84 views

How to connect custom stm32 board to debugger

I have a custom STM32 microcontroller board. I have verified all of the electrical connections, and I am able to program the board with Texane's st-flash utility. However, I would like to debug the ...
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1answer
88 views

ESP32 logic HIGH/LOW level voltage, not working?

From ESP32 datasheet: In my case: VDD = 3.3V Vil (max) = 0.25 * 3.3 = 0.825V Vih (min) = 0.75 * 3.3 = 2.475V Theoretically: LOW LEVEL range is -0.3V to 0.825V HIGH LEVEL range is 2.475V to 3.6V ...
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1answer
48 views

Video stream through microcontroller wifi

i am currently following an education in technical informatics(mostly micro controllers programming). I always wondered how to send video frames though an cheap micro controller, but after googling a ...
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1answer
137 views

Whats the most effective int on a 8-Bit Microcontroller? [closed]

The size of an int is defined by the compiler, not by the processor. Thats why e.g. int_8 exist. However, I was thought that usually int is the most effective datatype. Is this still true when e.g. ...
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1answer
42 views

EEPROM Interface confusion with Address?

So im researching how to interface with a EEPROM Chip via I2C with an AVR (Still learning a lot of the interfacing). Anyways, the AT24C16 for instance (or that family of EEPROM) seem pretty popular. ...
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2answers
41 views

Read temperature sensor from microcontroller to Android application (via microUSB)

I'm working on a concept for a project, and I'm having difficulty determining whether this application is possible. I will have some misc. microcontroller with an attached temperature sensor, and ...
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1answer
62 views

BLDC Motor rotor vibrates with audible high pitch beep, but does not spin. Controlled by custom motor controller

The circuit I have built (taken from the HIP4086A gate driver data sheet found at https://www.intersil.com/content/dam/intersil/documents/hip4/hip4086-a.pdf) is: The only difference between this ...
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1answer
108 views

Systems similar to TI's PRUs [closed]

I have been working with TI's PRUs on the am335x, equipped on the BeagleBone Black. I would like to know if other hardware manufactures offer similar systems. I am doing my Bachelor Thesis on this ...
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2answers
77 views

Sending few commands with BLE without microcontroller

I am completely new to electrical engineering, but I am trying to build a small device with three buttons circuit, each one of them would send a different command to the mobile phone via Bluetooth low ...
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2answers
64 views

Attiny45 12V LED Driver

I want a fading effect on a 12V led strip when power is turned on/off. I want to keep it simple and efficient, so I choose an Attiny45. The problem is that for the Attiny to work, I would first need ...
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1answer
86 views

ModBus Timeout Error

Anyone very experienced with Modbus & RS-485??? My task is to control a DC motor using micro PIC24. The motor setting like the angle, delay, start/stop, duty cycle, etc will be sent from PC using ...
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1answer
179 views

C Language Pointers Question [closed]

Not sure if this is the correct place to post a programming based question so will have a go anyway. Attached below is a piece of code and a table where I have to fill in the blanks. Just to clarify, ...
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1answer
102 views

microcontroller is “hanging” when it is feeding PWM to a DC motor controller

I am using linear potentiometer to control the speed of a DC motor. I am using the following schematic. An ATmega328P receives the value from linear potentiometer via analog read. This ATmega328P ...
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1answer
229 views

AVR: Pullup vs Pulldown on button input?

So I know the Atmega328p (What im using now) has Pull-up resistors available to be activated. And I know when reading input we could either make a button cause a PIN to go high or low....but is there ...
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0answers
40 views

minimalist serial port addon to a basic 8052

Currently I have two microcontrollers connected to each other so that I have two serial ports. One to the PC and one to a wireless radio module. Now I'm considering replacing one microcontroller with ...