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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2answers
42 views

STM32F power supply sequencing with 5-volt tolerant pins

The STM32F427 is powered by 3.3V but many of it's pins are 5V tolerant. This allows external chips to drive it's logic I/O pins at 5V without damaging the device. I have a board design with at ...
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4answers
94 views

Is my STM32F103C8T6 bricked? [on hold]

]2I recently started learning how to develop on the STM32F103C8T6. I got the Mastering STM book and followed it to run the first program, which was blinking the onboard LED. I ran the code and made ...
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0answers
74 views

Can I connect two MCUs directly to one micro SD card without additional components?

I am new to this community so I am sorry if I'm asking in a wrong place or something out of topic. I think I have considered everything. :) So, now the basic info: I am working on a project which ...
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0answers
29 views

EFM32GG942F1024 is not working

I have used EFM32GG942F1024 MCU powered from its own internal voltage regulator(3V3). My remaining circuit also takes same 3V3 and its consumption is around 50-60mA max. One strange thing I noticed ...
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1answer
93 views

uC IO pin driven “low”, but voltage sits at 0.3V, not 0V

This is an Arduino MKR WiFi 1010 board, which runs at 3.3V. PA18_OTG is an IO pin, which by default is driven HIGH (3.3V). In this state I measure the OTG pin at 0V. I need to drive OTG high, so my ...
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0answers
49 views

AWG 30 cable distance for 3.3V from ESP32

I'm planing to put some magnetic switches on my windows and pulling the wires up to the attic and use an ESP32 to notify via MQTT when they are opened/closed. I went to my local electronics store and ...
2
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2answers
143 views

What is the best way to limit voltage of a solar panel?

I am using a 6V 6W solar panel with the Particle Boron microcontroller with a battery pack. I want to ensure that the voltage supplied by the solar panel does not surpass 6.2V, as that is the max ...
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1answer
73 views

STM32L053C8 Questions on power schematic [on hold]

I am developing a low power board using the STM32L053C8T6TR and have written a schematic to power the board with a 3V coin cell battery and have a few questions. The datasheet mentions N x 100nf + 1 ...
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4answers
81 views

How can I control 2 or more seven segments displays using a single microcontroller?

Is it possible to control say up to 4 seven segments displays using a single microcontroller and having some I/O ports left? For example, say I would like to show a reading with 4 seven segments ...
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1answer
73 views

LED strip keeps blowing transistor

I made two LED controllers using an ESP. On the PCB I'm using three 2N2222 transistors + resistor (1k Ohm) at the base to control the 12V circuit powering the LED strips by applying 3.3V from the ESP. ...
1
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1answer
24 views

MSP-GANG programmer standalone script?

I have a project that uses 2 separate MSP430 microcontrollers. Both of them need to have different firmware uploaded to them. My place of work use the 8-way MSP-GANG programmers to program instruments ...
2
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3answers
83 views

What does “DC Current VCC and GND Pins” in ATmega8 datasheet mean?

I'm using for some DIY project ATmega8-16PU, during the reading of the datasheet (Datasheet Revision 2486AA–AVR–02/2013 ) I've encountered in section "Electrical Characteristics – TA = -40°C to 85°...
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2answers
74 views

Arduino - Not outputting 2 separate signals

I’m trying to get an Arduino to output 2 signals with different frequencies for a project.The schematic of the circuit is shown below. I’m trying to experiment using Pulse Width Modulation to give me ...
2
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2answers
70 views

What is “high voltage programming”, and why do some MCUs use it?

This article on sub-10 cent MCUs mentions that many of them use a high voltage programming interface. What is this, and why would a product use it over a "regular" 5V or 3.3V programming interface?
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2answers
70 views

How to interface with SMD pads to a custom MCU on PCB

I have a board that I want to remove the existing microcontroller and apply my own. I'll be swapping out one brand of microcontroller and putting in something completely different and so I intend to ...
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0answers
37 views

Mecrisp-Stellaris Forth on TI Tiva C LaunchPad

I'm currently trying to load mecrisp forth on a spare tiva c series launchpad (TM4C123) board I have at home and am not having much success. I'm an electrical engineering student and while I've ...
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0answers
24 views

DC charger Control Unit [on hold]

I would like to develop a DC charger for my EV, according the CCS and for the Control Unit, I am not sure what type should I choose: The interface between the Power Control Unit and the Control Unit ...
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0answers
13 views

SX1272 LoRa Chip Configuration

I'm Using SX1272 LoRa and want to interface with ST's MCU which has SPI and my question is Can I program the SX1272 as conventional SPI..? or is there any special procedure to be followed..? I don't ...
3
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3answers
726 views

Programming of ICs in general (MCU / FPGA / Serdes IC) [on hold]

I have a general basic question. Most of the Integrated circuits (apart from power IC) that are used in applications (Data transmission/communication IC) require some sort of programming or ...
0
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2answers
69 views

Programmable gain non inverting amplifier

I'm a hobbyist and like to design my own tools rather than buying chinese "kits" that teach nothing. I have been needing all sorts of amplifiers for different things and usually I would just use an ...
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2answers
65 views

Best way to determine power consumption of a microcontroller

What is the best way to determine the power consumption of a microcontroller? Need to select the right voltage regulator to supply 3.3V for PIC32MX795F512H.
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28 views

HC908 MCU Programming

I'm trying to program an MC68HC908QB8 MCU by attempting to enter monitor mode using this circuit: The requirements for entering monitor mode are in this table: But when trying to connect using the ...
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1answer
45 views

Overvoltage Protection Circuit for 5V limit

I found surfing internet an overvoltage protection circuit where I need to choose the value of R1 and D1 to set the value of the trip voltage to protect the load circuit. How should I correctly ...
2
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1answer
74 views

Complete synchronous USART implementation [closed]

I've been studying about USARTs and I haven't seen a consensus on synchronous USART implementation among MCU producers. First of all, there are transmit and receiver clock lines on some serial ...
2
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1answer
33 views

SAMD21 1μs timer handler taking longer than the timer period?

Before I begin I'd like to mention that I'm relatively new to working with microcontrollers at this low level, so please bear with me. I am trying to use an Adafruit Trinket M0 to process and ...
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1answer
35 views

Detecting signal / amplitude from 2 wire DC speaker

I want to create a circuit that replaces a 2 wire speaker in an existing electronic device. I want the device to be able to trigger an output when the amplitude of the signal that would regularly ...
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0answers
64 views

Why is shorting power connection required to start microcontroller?

I made a large-scale multi-circuit setup. Some parts are connected via ribbon cable and the LCD unit is connected via a 3 foot RS232 cable. The data rate through all cables is low since the main ...
2
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3answers
80 views

Where can I find a list of PIC microcontrollers programmable and debuggable with a PICkit 2? [on hold]

Where can I find a list of PIC microcontrollers that I can program and debug using a PICkit 2 in MPLAB X? I am a hobbyist who would like to breadboard prototype a new project based on a PIC ...
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2answers
343 views

Can an SPI slave start a transmission in full-duplex mode?

As far as I know, SPI transmission for an SPI slave works like below: Master selects a slave using SS pin Master and slave send data to each other simultaneously Master starts clock and data ...
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1answer
51 views

How to calculate current limiter resistors for ULN2803 and Relay?

I'm designing a digital I/O, and for the outputs I have ULN2803 and relays. I have the schematic below. The coil current of relay is 16.7mA, ULN2803's max input current is 1.35mA and output current ...
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4answers
886 views

Bare-metal start-up code for Cortex M3 .bss region initialization

I have developed inspired from here a bare metal start-up code for arm cortex M3. However, I encounter the following problem: suppose I declare an uninitialized global variable, say of type unsigned ...
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1answer
85 views

Where should hardcoded variables typically be stored in FLASH on a microcontroller?

I want to store calibration data on a microcontroller (namely the STM32 line) however with a large amount of flash memory available to ustilise, I wondered if there is a standard area of memory that ...
2
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1answer
84 views

Extending PCB switches and LEDs

I have a project where for the prototype, I'm using some off-the-shelf components, namely drone cameras and DVR boards installed in a car. The DVR board has a status LED and a momentary switch which ...
1
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1answer
40 views

Using multiple TCA9548A multiplexers

The case is that I have 5 temperature sensors. I want to connect 4 of them to the first TCA9548A (TCAADDR0), the SDA and SCL busses (from the ports 0 to 3) and connect the fifth one to the second ...
1
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1answer
69 views

How to define the SPI pins in an ESP32 module?

I am working on a project where I am integrating BME688 ,CAN, LoRa, SD card, ePaper display and WiFi module. I am using the board Heltec LoRa V2. And I have found this pin diagram. What I don't ...
2
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2answers
85 views

ARM Instruction size vs Instruction encoding

I cannot make sense of the difference between 'Instruction size' and 'Instruction encoding' specially about ARM and Thumb ISA's as explained here: Can we say that Instruction size is 32 bits but its ...
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2answers
85 views

Trouble understanding the hardware debugger concept in an MCU [closed]

When we write a program code to be used for a MCU in C and compile it by using an IDE, the IDE by the help of the compiler already shows us all the possible mistakes. For instance, if I type: ...
2
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2answers
133 views

PIC microcontroller programmer/debugger tools for beginner

I am a final year student and am going to use a PIC device for my project, so am getting familiar with it early. I will be using MPLAB X IDE to program the PIC. How is the code actually downloaded ...
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1answer
39 views

Level shifting between SD Card and Lipo-powered microcontroller

I have an ATtiny861 microcontroller powered directly from a Lipo battery. My circuit is designed to operate on supply voltages from 3V - 4.2V (bonus if it tolerates up to 4.6V). I need to interface ...
2
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0answers
77 views

How to measure currents between 0.1mA and 100mA? [closed]

Summary of question: I need to measure (using a microcontroller, not via a meter) currents between 0.1mA and 100mA, with a reasonable level of accuracy - say, to within 0.2 of a mA. My power supply ...
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0answers
29 views

how to update firmware of L476RG with TrueStudio (updating Hal functions) [closed]

I am using TrueStudio for STM32CubeMx project of developing L476RG, which has 1M memory FLASH, and we will update the firmware in FLASH. 1, If I put some user codes into one special region in FLASH, ...
0
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1answer
57 views

Multiplex Analog pin and digital pin on single pin

I have to manage one single analog pin with other digital IO. I am using a PIC micro, where I have utilized all the pins and I want one more pin for analog input. At the current stage, I can not ...
0
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2answers
46 views

How to connect MCU input pin with LED and Button?

I want to connect a LED and Push button on the GPIO input pin of a MCU, STM32F103 so that when the push button is pressed then the state of LED indicates the button is pressed. Is it possible to ...
0
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2answers
70 views

WS2811 timing issue

The datasheet says if the data line stays low for more than 50µs then the data will latch. From my testing I found that in between two 24-bit packets I cannot wait more than 2-3µs, else it will latch ...
0
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1answer
79 views

Zener Diode in Parallel with a Resistor which in turn is parallel to a Capacitor

I'm not sure I understand the purpose of a resistor in parallel to a capacitor and then in addition a zener. Initially, I thought it was a voltage regulator but there's no resistor between power ...
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1answer
106 views

Digital inputs problem [duplicate]

I'm designing a digital I/O module which isolated with optocouplers. I'm done with the outputs, but having a confusion about input side. I will have some switches and sensors to read as inputs, but ...
1
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2answers
147 views

How to calculate a resistor needed for an LED [duplicate]

I am building a backlit button box for my PC and the controller has 2x 5 V power supplies on it from the USB. I am using 7 of these LEDs and the power specs are at the botton of this post. The ...
0
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1answer
38 views

Xmos MCU implementation on PCB

I am trying to design af system using the XUF-208-256-TQ64 Xmos controller (https://www.xmos.com/download/XUF208-256-TQ64-Datasheet(1.16).pdf). The system should get an audio stream from USB, upsample ...
0
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1answer
102 views

Minimum requirements to interact with PCI Express

I have a relatively simple project (from the user point of view) in mind. I want to develop a very simple PCI Express (x1) card that users can put into their system and toggle some GPIO's from a GUI ...
0
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2answers
96 views

I/O Module with optocouplers

I'm designing an I/O module by using optocouplers for the inputs and outputs which I want to control by a microcontroller. Here are my questions: In the datasheet of optocoupler's output current (...