interface PIC16F877A with SIM900A GSM module - c

I've tried to interface PIC16F877A with SIM800l V2.2 in order to send sensor data from the microcontroller. While connecting SIM800L with proteus using TTL connection all the data are sent through GSM as we expected. But while we upload the code to the PIC16F877A, there is no response from the GSM module. I've also checked the baud rate, Tx and Rx configuration, changed the PIC16F877A but we can't obtain the results. I also changed the GSM module to SIM900A but still it's not working. Is there anyone who can help me with this issue please.enter image description here

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Serial Port Communication problem while using UART

I'm trying to send and receive data between a board (Dialog DA14531) and a simulation application of a temperature sensor.
I can easily send and receive data between the board and my computer, using Termite for instance.
By using Com0Com, I can receive the data sent from the sensor simulator in Termite as well.
However; I can't directly send data between this simulator and my board. I'm using Advanced Serial Port Monitor application and while the simulator states that the connection has been established, there seem to be nothing going on with this port.
Does someone have any idea about what might have caused the problem and how should I proceed for debugging?
So, I've figured out a new way to fix the issue:
Created a pair of virtual ports by using Com0COM.
Connected the simulator to one of these ports and Termite to the other one.
Connected the board to the system.
Used port forwarding in Termite to send the received data to the board.
This way, I can also monitor the data traffic between the board and the simulator.

Problem while uploading code in arduino atmega2560

I have arduino atmega2560 when i upload blink code than it shows error
avrdude: stk500v2_ReceiveMessage(): timeout.
I have checked the COM port is correct also that the driver is correctly installed.
Why would I be receiving a timeout error?
The possible reasons:
Faulty communication cable
Wrong com port selected
Wrong device model selected
Baud rate settings
Driver related issues
I think your arduino got bricked. But first try to reconnect it and upload your program.
Second try to disconnect any rx or tx pin connected. Third if your arduino is bricked, try to check this article for full solution of bricked arduino. Programmer is not responding arduino

STM32 USB CDC did not work

I'm using stm32l151 and I want to use usb peripheral in cdc mode. I used stm32 cubeMx to generate the project. however the function CDC_Transmit_FS() always return USBD_BUSY. can anyone help me?
Here is my code:
while (1)
{
CDC_Transmit_FS(Buffer, 6);
HAL_Delay(2000);
}
I only added the above code to the project created by STM32cubeMX but it didn't work.
STM library is buggy and it stalls when you for example try to send many larger packets of data.
There is a problem with the windows drivers and there are quite long delays between packets. So 12MB is quite difficult to archive - using CubeMx I could only have about 3-4Mb (12MB when packet is sent).
Another problem I had - I needed to send some data to the device bofore I could transmit next packet (max 8kB in my case), otherwise it stalled randomly.
Fortunately, the problem is solved and I can receive data in the PC from the STM32. There was a problem in my terminal software. I used serial port manitor to monitor the received data from the serial port, however this serial monitor software do not open the serial port by itself and if any other software opens the serial port and receives the data, it monitors data receptions. I didn't know that.
Thanks

Sending tcp/ip packet( or MQTT packet) from ARM cortex-m4 microcontroller UART to telit modem

I am currently using NXP micro-controller which is ARM-Cortex-m4.
I want to use UART of micro-controller to connect to UART of Telit Modem.
Are there any helpful links where I can get source code or links for sending tcp/ip packet from microcontroller to modem using UART as communication channel.
Can I send directly MQTT packet from UART to Telit modem?(Another sub question)
What protocol should I follow?
Telit modems provide a wide set of AT commands for TCP/UDP, so you can send through them any data based on protocol that is conveyed through TCP/UDP, and this includes MQTT.
Explaining all sockets-related AT commands would be too wide. I can suggest starting with the following command (you can find them in AT command user guide):
AT#SD
AT#SH
AT#SCFG
All commands related to PDP context activation, such as +CGDCONT, #SGACT and so on.

Data transfer using xbee and arduino

i have a portable device that consist of
arduino leonardo board,xbee series 2 as router( AT mode ) and different sensors.This portable device acts as a remote device and can be used upon power up.
The other side, i have a host controller that consist of arduino uno board, arduinoxbee shield v1.1, and xbee series 2 as coordinator( AT mode ). This host controller is plug through USB into my PC.
The aim of my project is to send the sensor data from the portable device using xbee wirelessly over to my host controller and displaying out on the arduino serial monitor.
I've managed to configured the two xbees. But now, i'm unsure of how im going to transmit and receive the data. I need a transmitter and receiver program for both xbees that is connected to the arduino. Anyone can help please?
There are a couple different options for how you can do this, but the simplest is to set up your sensor XBee either in change detect (IC) mode, or set a sample rate (IR). In either case you'll need to handle the RX Indicator frame at the controller, which will contain the sampled data.
I wrote a C# stack that can configure all this, but for what you're trying to do it would probably only be useful as a reference (https://github.com/jefffhaynes/XBee).

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