Communication using RS232 and MAX232 circuit
The RS232 standard is a widely used serial communication protocol that facilitates data exchange between devices. It operates with a voltage level of ±12V, which is not directly compatible with the TTL logic levels (0V and 5V) used by microcontrollers like the 89S51. The UART (Universal Asynchronous Receiver-Transmitter) integrated into the 89S51 microcontroller enables asynchronous serial communication by allowing the microcontroller to send and receive data in a serial format.
To bridge the voltage level difference, the MAX232 integrated circuit is employed. This IC contains a pair of level shifters that convert the TTL signals from the microcontroller to the RS232 voltage levels required for communication. The MAX232 typically requires a +5V power supply and generates the necessary negative voltage levels internally, enabling it to convert the signals appropriately.
In a typical application, the microcontroller sends data through its UART, which transmits the TTL-level signals to the MAX232. The MAX232 then converts these signals to RS232 levels and transmits them to the receiving device. Conversely, when data is received from an RS232 device, the MAX232 converts the RS232 signals back to TTL levels before sending them to the microcontroller's UART.
This communication setup is commonly used in various applications, including data logging, remote control systems, and interfacing with computers and other serial devices. The implementation of RS232 communication using the 89S51 microcontroller and the MAX232 IC provides a reliable and efficient means of data exchange in digital systems.One of the most powerful communication to be implemented in a digital system is communication using RS232 serial line. Microcontroller 89s51 have facilitie a UART, so that it can perform serial communication with RS2322-level inter-equipment or with the computer.
IC MAX232 is enabled to change the format of TTL to RS232. 🔗 External reference
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