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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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34 views

Trouble getting I2C working on STM32 (stm32f103c8t6)

I'm starting out with I2C. I have a development board with stm32f103c8t6 to which I have connected GY-68 board with BMP180 barometric pressure sensor. Documentation of BMP180 describes Chip-id ...
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52 views

How can we determine memory usage of a microcontroller

How can we determine how much memory is being used, or will be used by firmware in a microcontroller? What tools can support this? Generally we don't use dynamic memory in embedded systems, but how ...
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1answer
41 views

How to write STM32F4 OTP Area

I am reading the reference manual page 75 that shows the flash memory organization of STM32F4 MCUs. There is an OTP area of 528 Bytes in it as shown in the image: Is it possible to write on this OTP ...
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33 views

Microprocessor (arduino) controlled Buck Converter / Step down regulator / Voltage Control Chip

I'm hoping you can help me select the proper chip for my task. I'm very new with circuit design so all the help would be greatly appreciated. I've done over 20 hours of research on this myself already ...
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1answer
39 views

Nautical map model navigation lights

I would like to create navigation light sequences on old admiralty map of my local area. There are lighthouses and channel markers in area with mix of flashing and times. The single flashes I can use ...
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1answer
40 views

PIC MCU and LCD display 16x2 - strange behavior

I have a LCD display 16x2 connected to a PIC32MX470F512L. On PIC32 I configure all the 6 pins used to interface with the LCD as open drain outputs on 5V tolerant pins, I have 4.7K pull-up on each line ...
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1answer
36 views

PWM offset for STM32F4

I generated a PWM signal with the STM32F407 board. All good, everything works fine but I realised that the output has an offset of 40 mV. Does anyone know why the PWM output never goes to zero even if ...
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1answer
19 views

Charge Measurement for Piezoelectric Sensor

I want to measure the charge displaced by a force acting on a piezoelectric sensor. The problem is I don't know the sensor so I have no idea how big the current generated by the sensor may be nor what ...
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2answers
64 views

How to analyze Microcontroller input-logic-signal without ADC?

I have a signal which is fed to one of the digital inputs of a microcontroller (PIC16F18326). The signal is shown in the image-1 below. This is during the normal operation of the circuit, that means ...
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1answer
35 views

Logic Analysis of a 8 bit mcu

I would like to sample the logic on the pins out out of a toy robot's processor and the MCU is an 8 bit processor that operates a max clock speed of 5 Mhz. Does anyone have any recommendations on how ...
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36 views

STM32CubeProg vs STLINK Utility

There are 2 software tools provided by ST to flash their STM32 MCUs namely STM32CubeProg and STLINK Utility STM32CubeProg Page says: STM32CubeProgrammer (STM32CubeProg) is an all-in-one multi-OS ...
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1answer
36 views

ST-LINK and PA13,14 Pins on STM32F407

If I use PA13,14 pins for flashing my MCU via ST-LINK programmer then can I also use these pins as GPIO in the same circuit? Will that not disturb the ST-Link if some analog or digital circuit is ...
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29 views

STM32F407 Selectable External or Internal Oscillator

I wonder if its possible to switch between external and internal oscillators at runtime? Can I do that configuration in CubeMX? The idea in to put a jumper on a GPIO pin to do the selection at runtime....
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1answer
33 views

Minimal circuit to flash STM32F4 using STLINK

I wonder if I need to put some circuit between STLINK and STM32F4 MCU to flash it or does it simply require to connect the wires 1:1 directly? I cannot find it in the datasheet.
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3answers
1k views

Why isn't there any EEPROM in STM32F4 MCUs?

Why isn't there any EEPROM in the STM32F4 series MCUs? Mostly I have Microchip MCUs and they have EEPROM available in them, but I just found out that it is not available in the STM32F4 MCUs... And it ...
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0answers
39 views

Embedded design with USB 3.1

I am trying to design a system that will transfer data between two storage devices on a PCB, preferably using USB 3.1 as speed is a major concern in this design. However, my understanding is that I ...
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2answers
96 views

RS485 vs RS232 similarity vs differences

I have used UART RS232 communication between MCUs extensively. Now I need to interface my STM32F407 MCU over RS485 bus with with devices. I have understood few things about RS485 but not-clear about ...
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27 views

Control digital intercom by wiring up the buttons [on hold]

I have an Aiphone GT-1C-L - pics below I was trying to measure if there is any special voltage happening when I open the door, but it all seems to be done digitally, so I think I will have to ...
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2answers
42 views

How to operate 1602 LCD on 3.3V [on hold]

I wonder if its possible to run a common 16x2 LCD with 3.3v power supply. Its datasheet shows supply voltage = 5V. Are there any 3.3V variants of 16x2 LCD modules?
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95 views

PIC16f88 not debugging

Disclaimer, i am more or a hardware designer and not so much a coder, i can code but i'm not the most proficient at it. I have a project I'm working on that has a portion of the code that appears to ...
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2answers
75 views

How to calculate bus load of CAN bus?

I have a few questions regarding CAN bus load Is there any derived equation/formula to calculate the bus load? I need transmit below frames(Assume Standard frame format) at baud rate 500 kbps on the ...
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0answers
50 views

LPC1768 internal RTC time register is not incrementing

Value is read right,but time is not incrementing. ...
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3answers
1k views

Does ATtiny RESET pin need a resistor?

I need to make sure that my ATtiny does not reset unexpectedly. To do that, I am planning on connecting the RESET pin directly to VCC. However, I have heard some places that you need a 10k resistor ...
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37 views

ADC to PWM problem [duplicate]

everyone, I hope you are all are having a good time... I am trying to write the code that applies PWM on leds according to the reading of a POTENTIOMETER, I faced a problem that the leds' lights do ...
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73 views

Stm32 hc-sr04 sensor code issues

I'm newbie in microcontrollers programming and trying to measure distance on stm32f103c8 by using HC-SR04 sensor. But sadly it doesn't want to work properly (edit: nothing happens when i try to turn ...
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1answer
40 views

ADC with PWM glitch

This code is for PWM works as long as the line ADCSRA |= (1 << ADSC); is commented out. But when I remove the comment, it doesn't work. I don't know why that ...
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2answers
40 views

I2C Put One Termination Res at the End or on Each Slave Board

I Have a system with I2C bus wired just like this: My questions is which one is better: put the termination pull up res at the end of connection (on the last board), or put pull up res on each slave ...
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29 views

PIC Micro Reset Issue - Decouple Help?

For the attached LED drive design I use a 5V external SMPS.But most of the time PIC wont starts up properly.Sometimes working & sometimes not. IC1 = PIC16F630, IC2 = 74HC595, C1 = 104 Ceramic, ...
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1answer
79 views

PWM with ADC - ATMega16

I want to write code where I move the wiper of the potentiometer clockwise so it applies PWM on a pin, and when I move it counter-clockwise it applies PWM on another pin. I could do it with Arduino, ...
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3answers
39 views

Really occasional malfunction of the Schmitt-trigger input

I'm using some Schmitt-trigger inputs for debouncing the interrupt problems. Referring to above circuit, the circuit has a RC circuit and the output of the RC circuit goes to the Schmitt-trigger IC(...
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1answer
35 views

I want to use 4x MicroServo with 9V battery

I have 4 Tower Pro MicroServo 9g SG90 I want to power with a battery. This is the datasheet I found online. I have a small breadboard and some resistors laying around (220, 1k, 10k), and a 9V battery....
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1answer
37 views

MASTER Clock output from one micro to another vs independent clock src

I have a Small STM32 Nucleo board where the on-board ST-Link debugger has an 8mhz crystal for the debugging microcontroller. That microcontroller is set up to output its MASTER clock, in other words ...
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1answer
49 views

RS485 Rx signal connected with two drivers

I wonder why is RS485_Rx is connected with two line drivers while RS485_Tx is connected with only one line driver. Is this some mistake in the schematics or is it some standard circuit for RS485?
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46 views

NMI Input circuit on a MCU

This circuit is connected at the NMI input of a MCU. The 'J2s' pin is connected to an external signal. Is it some sort of delay circuit or some filter circuit? Edit: J2s is digital signal coming ...
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1answer
46 views

GPIO Configured as Input OR Output

Is it possible to identify looking at the schematics whether a GPIO pin is configured as Input or Output pin for the case in following image? PIN93 and PIN94 of a MCU are connected directly with ...
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1answer
87 views

Cheapest way to run a 32 bin FFT on audio signals [closed]

I am working on a project that requires me to run the FFT algorithm on analog audio frequencies to switch on LEDs for the corresponding frequency(...
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2answers
73 views

STM32F407VG Pin Assignment

I am new to the STM32 world. I am using [STM32F407VG]1 (100 Pins pkg). I have to select an 8-bit port for connecting 8 digital inputs to the MCU.. but the datasheet shows so many alternate as well as ...
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1answer
50 views

Optocoupler 5V to STM32F407 3.3V

I have to connect 8 optocouplers as shown in the picture with STM32F407 MCU. These are giving 8 digital signals to the MCU. The supply voltage at the outputs of optocouplers is 5V DC while the ...
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0answers
59 views

Analog input and high current output in one IO-pin

I am designing a more or less modular I/O Card and I need to supply a switchable 24V high current output for some sensors and also want to use the same port as an analog input for sensing voltages up ...
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1answer
68 views

Fingerprint scanning repeatedly

I am using 2 fingerprint module to make an attendance machine. Normally i have seen the attendance machines just need the user to put his/her finger on the scanner and it is scanned.. then next ...
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1answer
29 views

MCU + MUX + Multiple gyros

Is it possible to get time synchronous samples from multiples gyros (16 is what I'm trying to use right now) using an MCU and a multiplexer? I'm new to HW/embedded SW, but I was testing some fusion ...
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1answer
93 views

Optocoupler is failing to isolate circuit

I have a circuit in which I am trying to use an microcontroller to activate a car horn. I've had a lot of trouble trying to isolate the horn from the rest of the circuit. I have the microcontroller ...
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1answer
33 views
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2answers
53 views

LED Matrix Leakage LEDs

I'm doing a LED matrix design and it's a cathode row design. Attached is a picture of my matrix design. The design works ok and I can show any pattern in the matrix. The problem is when a leak LED ...
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2answers
66 views

Trouble getting USART working on STM32 (stm32f103c8t6)

I started working with with stm32f103c8t6 recently and I was able to set GPIO to input and output, however when I try to set USART it just does not work. I'm trying to write directly to registers, ...
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2answers
93 views

Any Methord to overcome Main supply voltage fluctuations with ADC value readings?

Updated: I have a circuit for monitoring fan regulator speed change using ADC (as shown). But the problem is: In case input supply voltage (230V) varies due to some over-voltage or short circuit, ...
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1answer
48 views

Current sensor that connected with fan regulator

Circuit diagram is shown Here input of FAN is connected to current sensor through a regulator My question is.. Is it ok to measure AC current through this sensing IC(ACS712) When fan speed changes ...
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1answer
121 views

Processor speed for generating PWM at 1 MHz

I want to generate square pulses at around 1 MHz to drive an H-bridge inverter. Now, I want to choose a suitable microcontroller, microprocessor, or a DSP board. I need to generate a few pulses (...
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55 views

Does the choice of microcontroller affect the memory package type I can use? [on hold]

I know this is probably a broad question, but actually I am hoping for a broad answer in this case. I have a microcontroller for which I need some external SDRAM memory. Let's say the memory's ...
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1answer
51 views

What are the use cases of FIFO Half-Full and Three-Quarter Full interrupts in Receive FIFO of a UART?

I am implementing a protocol decoder which receives bytes through UART of a microcontroller. The ISR takes bytes from the UART peripheral and puts it in a ring buffer. The main loop reads from the ...