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0
votes
1answer
85 views

Serial line switching through a transistor

I want to switch my RS-232 TX pin.For this I am using NPN transistor in between the TX line in such a way that the collector terminal is connected to controller side and Emitter to external side. ...
1
vote
2answers
109 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, ...
3
votes
4answers
639 views

UART sometimes missing first few characters on ATmega328P

I wrote some code for the ATmega328P, (Packaged in a module that clones the Arduino Nano). Normally when I send UART data from my computer to these micros, it is received just fine. However I have ...
1
vote
2answers
153 views

How to disable arduino Hardware Serial Rx Interrupt Properly

Intro: I have an Arduino mega doing multiple tasks , from which A function Reads data from a sensor using SPI . Every like 10,000 read or something , i get 1 error bit in the SPI data . and I have ...
0
votes
2answers
89 views

Analog Potentiometer Output to USB Serial [closed]

I‘m working on a project which has several switches and potentiometers that will be used to control parameters in software via (e.g.) MIDI and would like to know how to get the pots set up without ...
0
votes
0answers
20 views

Checking HM-TRP radio adapter for initial data

I have several HM-TRP radio adapters (consisting of the HM-TRP chip with a female header connected to it) of the same version. I tested it in a mini circuit where the PC does direct I/O with the HM-...
0
votes
0answers
48 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 ...
0
votes
3answers
122 views

What exactly are low speed devices? [closed]

The definition of I2C is - "A multi-master multi-slave serial bus used for communication between low-speed devices". However, I have been searching the web for a concrete explanation for this but ...
1
vote
1answer
114 views

PISO shift register to USB

I have ~26 parallel inputs that I would like serialize and send to a computer over USB. I decided to chain together 4 LS165 parallel-in serial-out shift registers, but I don't know how I would send ...
0
votes
0answers
206 views

stm32f103 - 16 bit mode SPI reading returns 0xFFFF

I am working with a sensor which communicates through SPI. I am trying to read MISO line, but it returns 0xFFFF. first I send 0xC000 on MOSI and the sensor places 0x0032 on MISO. I read MISO using ...
2
votes
2answers
1k views

Upgrade user application using custom bootloader via UART (STM32)

I'm using an STM32L4 board and my flash memory looks like this: |______________ | | USER application | | |______________ |Vector table(UA) |______________ 0x8000 - 8000 | | ...
0
votes
0answers
49 views

resistor at external clock source line [duplicate]

im reading a arm based mcu board schematic and there is 100R resistor (R30) at external 25MHz oscillator source. What is the main reason of using serial resistor at clock line ?
2
votes
2answers
495 views

FIFO circular buffer size in over UART

I am trying to implement an UART protocol to make communication between two boards. data are ascii encoded and messages length's are variables. I've chosen to implement a packet in order to "...
1
vote
1answer
301 views

Low level details for serial communication between UART of a microcontroller and PC [closed]

I want to understand how exactly full duplex serial communication between UART of a microcontroler and PC com port actually happen ? I have used applications where a single UART( single Rx, Tx pins) ...
1
vote
2answers
2k views

USART interrupt not working as expected [STM32 Nucleo]

could someone explain why i can only receive 13 chars with USART interrupt? I use '\n' to detect the end of string. ...
0
votes
1answer
237 views

Simpler code than bit banging to get multiple serial hardware working with 8051

I created a circuit like the following: I have sub-circuits that all take serial data as input and do miscellaneous processing with it. Most of the sub-circuits are just light displays. I want to ...
1
vote
1answer
138 views

Memory dump size does not match size of MTD partition

Device with Linux embedded system on NAND flash memory. I did memory dump of some MTD devices partitions use serial console, from U-boot bootloader use available commands. First I read MTD partition ...
0
votes
0answers
184 views

Multiple serial ports to an old 8051 I have numerous of

Ok, I own quite a few of the AT89S52 IC and the AT89C4051. Both have only UART, but my project requires two because the same device will control a radio module that requires a UART for interfacing and ...
-1
votes
2answers
802 views

UART speed limitation factors? [duplicate]

I want to ask about using UART to send data from uC to PC. So I have some questions. I wonder what is the maximum of the UART bit rate? What factors affect the UART speed? For example does using DMA ...
0
votes
1answer
795 views

Serial Over USB Reading With GNU Octave Problems

I am having difficulty reading a USB virtual comm port into GNU Octave, and there are some bizarre goings-on that I would like some input on. Currently I have a USB CDC virtual comm port device that ...
0
votes
1answer
2k views

How to interface SIM800L to UART on STM32F103

I have problem to interface SIM800L with STM32F103. I just read SIM800L datasheet that UART logic level is on 2.8 V. But the STM32F103,can be operated in 3.3 V. I connected my TX RX pin directly to my ...
1
vote
1answer
88 views

UART continues to receive despite cable is unplugged!

I have a custom DSP board which has a UART port to send data to PC. Strange thing is when I stop the UART port on DSP, PC still continues to receive data. Even stranger, I unplugged the USB cable from ...
0
votes
1answer
369 views

Serial communication with microcontrollers AT89S52

I have a problem, I need to connect two microcontrollers and programming one of those as a transmitter and the other as a receiver, I've tried to do this but it's not working, and I don't know why. ...
0
votes
3answers
259 views

Controlling hardware with serial port [closed]

I initially posted this in SuperUser SE Site, but it was recommended that I bring it here instead. So, here we go :) We have a 'dated' security system at the office. It is a model that was made (or ...
0
votes
1answer
345 views

UART Tx stops working without UART Rx connected

So my problem is that when I have both Tx and Rx connected to an FTDI cable with ground connected as well. When I have both cables connected I can send message as expected. But as soon as I disconnect ...
-3
votes
1answer
106 views

Microcontroller design [closed]

I would like to use ATmega 328 micro-controller to perform the following functions: 1) UART connection to GSM modem 2) Serial connection to the single board computer's power reset pin 3) Serial ...
0
votes
0answers
71 views

How fast can I pipe data through a TI Delfino in 1.5 KB chunks?

Say I program a Delfino with this C snippet: ...
1
vote
1answer
579 views

STM32F4 serial RXNE flag

I am trying to receive serial on a stm32f411. I decided to monitor the the RXNE flag to check the serial buffer. I can get the flag to work, however, the issue is that I do not think it is working ...
0
votes
1answer
1k views

How to control thermal printer from micro-controller and choose it

The project is to print barcode and some text with thermal printer using micro-controller. Initially I chose RP58 which has this command set and serial port. So to control the printer, do I just ...
3
votes
3answers
2k views

Is there any way to use Half Duplex RS485 without using a dedicated controller pin for RE - DE?

I have attached the reference circuit I am using for a simple MODBUS (Read Coil) communication application. I am short of Pins on my controller and I do not want to use a dedicated controller pin for ...
0
votes
4answers
271 views

Resistors in serial communcation

In my still relatively short journey into the world of electronics, I have stumbled on multiple schematics that use resistors in serial communication and suspect that they are there for some kind of ...
0
votes
2answers
188 views

Why Data Recovery Block needs to operate at 16 times the baud rate [duplicate]

The data is received on the RXx/DTx pin and drives the data recovery block. The data recovery block is actually a high-speed shifter operating at 16 times the baud rate, whereas the serial Receive ...
1
vote
2answers
207 views

Most cost-efficient way to implement USB full-speed host? [closed]

I need to a device which can act as a USB host to send various chunks of static binary data periodically to a full-peed USB serial peripheral of FT232 type (RS-232-ish UART). I was thinking maybe ...
0
votes
1answer
306 views

AVR: Serial communication gives strange characters

I am having some serious problems trying to get the serial monitor to output the correct characters. I have looked over a lot of the posts with similar problems, but nothing seems to solve it. I am ...
3
votes
3answers
2k views

Serial Output returns wrong ASCII

I am using a FTDI cable and connected it with my mac. I can connect successfully with my serial terminal on my mac via the cable and can input text on my keyboard to be transmitted to the AVR. When ...
3
votes
2answers
1k views

STM32 SPI: strange behavior on empty TXFIFO (previous bytes history?)

The following code configures and enables SPI2 as slave on my STM32F303RE board, writes 0xAA, 0xBB, 0xCC, 0xDD bytes to DR register and loops in a while(1): ...
-2
votes
1answer
649 views

Differences between isolated and non isolated usb to RS485/RS232 converters [closed]

What are the differences between isolated and non isolated usb to RS485/RS232 converters
0
votes
2answers
82 views

Need of Crystal (During UART Programming A Bare SI-Tiny-Gecko Chip)

I'm trying to set up a proper circuit for a bare chip (currently I have EFM32TG222F32 under my reach but I want to be able to work with any chip I get.) I'm setting up my circuit on a breadboard ...
1
vote
4answers
355 views

Errors transmitting 10 bit number read with Atmega328 via serial and reading it with “od”

I have ATMEGA328P-PU and I have hooked up the photocell to it. I'm using the following code to read the analog values and send them back to computer for debugging. ...
1
vote
2answers
204 views

Indecipherable Data on Serial Monitor

I have ready made working electronic product. I am applying reverse engineering on it. The WiFi module is connected to micro-controller via UART( RX & TX). The android app sends command to WiFi ...
0
votes
1answer
168 views

How to interface Si8902 with ATmega128rfa1?

The ATtmega128rfa1 works as master and Si8902 works as slave that is okay. But when a request is given Si8902 takes 8us to reply back with the ADC data. How can master wait for 8 us. How to ...
0
votes
1answer
272 views

FIFO ASF drivers and USART avr problem sending and recieve data via rs232 connection

I'm working to send frame of 8 bytes to Micro-controller Xmega128a1 (via RS485). The frame looks like this: {header1,header2,CMD,D1,D2,D3,D4,CRC} For example: <...
-1
votes
3answers
235 views

Confused about how microcontroller board and computer communicate

I recently got myself FRDM K64F board and got myself occupied with the following questions: Does the compiled hex code i send to my board has to go to the UART chip prior going into ...
0
votes
1answer
125 views

If current consumption of serial flash SST26VF064B is 15mAq104MHZ then at 50MHZ it is 7.5?

I am Mohan working in Germany. For my data logger project i choose SST26VF064B serial flash. My data logger should consume lowest power possible. I see that SST26VF064B is consuming 15mA@104MHZ. In my ...
1
vote
3answers
12k views

Uart Full Duplex vs Half Duplex

When uC1 wants to talk to uC2 via uart, the Tx of uC1 is connected to Rx of uC2 and vice versa. Half Duplex states that only 1 uC can use the communication line at a time and Full Duplex states that ...
1
vote
1answer
432 views

Does Interrupting a Microcontroller Data Receive with a Higher Priority Interrupt Cause Data Loss?

I would like to know what would happen if a Serial Terminal were to send a large amount of data to a PIC/AVR, for example over USART interrupt, which was then interrupted by a higher priority ...
0
votes
1answer
218 views

10Mbs USB to serial communication

I want to transfer data from a full duplex serial device (TTL) to the PC. The data rate is 10Mbs , i am investigating potential solution. I can add a level converter like max232. I have 2 questions: ...
0
votes
1answer
92 views

High 4bit crash in atmega128 serial communication

I am trying to communication between atmega128 and serialCom(PC), but I get a pretty strange bug. When I send data 0 to 255 (char) from atmega128 to serialCom(PC) ,after sending 0x08, the high bit ...
4
votes
2answers
2k views

UART synchronization [duplicate]

I am trying to understand UART synchronization. In a UART, the default state is high, and it starts the reception process when it receives a start bit (high-to-low transition) In some scenarios any ...
0
votes
1answer
189 views

Using several microcontrollers as nodes in a neural network [closed]

I recently read an EETimes article about Google's neural network experiment, where they used several processor cores as nodes in a neural network. That made me wonder: could it be possible to ...