Visual Basic & AVR RS232 interface

This project involves controlling an AVR microcontroller (MCU) using Visual Basic 6. The applications of this circuit are numerous, enabling the creation of various devices that require control from a Personal Computer (PC) or any circuit that collects data from sensors. The data is transmitted to Visual Basic-based software via the RS232 port. It is important to note that this project is presented in a generic format to illustrate the concept of controlling an MCU through a serial port. Modifications to the source code for personal use are permitted, but commercial use of this project is prohibited. For experimental purposes, an AVR development unit such as MCU100, STK200, STK500, or an AVR development board with 8 LEDs, 5 switches, and an RS232 chip like MAX232 or MAX202 can be utilized. The software, named "AVR RS232 Interface," is developed in Visual Basic 6 and consists of a main window and an "About" window. In the main interface, users can select the COM port connected to the AVR board (referring to the spare RS232 connector, not the programming connector). The "Switches on Interface" window displays 5 green circles; pressing any of these 5 switches on the AVR board will change the corresponding circle to red. The value of the received character is displayed in binary format in a text box below. The "LEDs on Interface" window features 8 green buttons; pressing a button will turn off the corresponding LED on the AVR board, and pressing it again will turn the LED back on. The value of the sent character is shown in both Decimal and ASCII format in two text boxes below.

The circuit design for this project emphasizes the integration between the AVR microcontroller and the Visual Basic 6 application, facilitating a user-friendly interface for controlling and monitoring the microcontroller's functions. The communication is established via the RS232 serial protocol, which allows for reliable data transmission between the PC and the MCU.

The AVR development board serves as the hardware platform for this project, equipped with essential components such as LEDs and switches. The LEDs provide visual feedback for the state of the microcontroller, while the switches allow user interaction. The RS232 interface, typically implemented using MAX232 or similar chips, converts the TTL-level signals from the MCU to the RS232 voltage levels, ensuring compatibility with the PC's serial port.

The Visual Basic 6 application acts as the user interface, enabling users to select the appropriate COM port for communication. The interface is designed to be intuitive, with clearly labeled buttons and indicators. The functionality of the switches is reflected in real-time on the interface, allowing users to monitor the status of the AVR board. The binary representation of received characters provides insight into the data being processed, while the LED control feature allows users to toggle the state of individual LEDs, enhancing the interactive experience.

Overall, this project exemplifies the practical application of microcontroller technology in conjunction with software development, showcasing how a simple serial communication protocol can be utilized to create versatile control systems for various applications.On this project we will control anAVR microcontroller (MCU) via Visual Basic 6. The applications of this circuit is countless. You can make, anything you want, that needs control from a Personal Computer (PC)or from anycircuit collects data from sensors. Finally, itsends these data to Visual Basic based software by using the RS232 port. You have to know, this project is in generic form, to give you the idea of controlling aMCU through a serial port. You can modify the source codes to make yourown circuit but onlyfor personal use. Any commercial use of this project is not allowed. You can use for your experiments, anAVR development unit such asMCU100, STK200, STK500 or an AVRdevelopment boardthat contains 8 LEDs, 5 switches or more and some RS232 chip like MAX232, MAX202 etc. The software is named "AVR RS232 interface" and it`s writtenin Visual Basic 6. It`s constituted by the main windowand "about" window. On the generic mask you can choose the COMport you have connected the AVR board ( For development boards I mean the spareRS232 connector, not the connector that you programming the MCUs ).

On the "Switches on interface" window, are5 green cycles. If you press any of these 5 switches on the AVR board, this cycle will be in red color. The value of the receivedcharacter canbe viewed in binary format, onthe below text box. On the "LEDs on interface" window, you will see 8 buttons with green color. When you press abutton you will see that the current led on AVR board will be turned-off. If you press it again, the LED will be turned-on. The value of the sentcharacter can be viewed in Decimal and ASCII format in two below text boxes. 🔗 External reference