#Uart embedded c program serial
#Uart embedded c program full
#Uart embedded c program code

in mode 1 the formula for baud rate is given by ((2^ SMOD )/32) * Timer 1 overflow frequency. This bit is used to double the baud rate of the timer in mode 1,2 and 3.įor e.g. Like TI this bit must also be cleared by the programmer. This bit is set automatically when one complete byte is received. This bit must be cleared by the programmer. This bit is set automatically when the transmission of one byte is complete. In mode 2 and 3, It stores the 9th bit during reception. In mode 1, it receives the stop bit(1 being a valid stop bit). I.e you can write into this bit and its content would be transmitted as the 9th bit in mode 2 and 3. In mode 2 and 3, it is used to transmit the 9th programmable bit. This bit must be set for enabling the reception. When you have a master device which wants to communicate to different slaves, Multiprocessor feature is used in mode 2 and 3. This bit is used for multiprocessor communication. Just like in mode 1, the baud rate can be adjusted by timer overflow frequency. Mode 3: This mode is same as that of mode 2 except that the baud rate is variable. Baud rate in Mode 2 is fixed.īaud rate = ((2^ SMOD )/64) * oscillator frequency. This bit is generally used for parity checking. Whereas during reception, this 9th bit is received and stored in the RB8 bit of SCON register. During transmission, the 9th bit transmitted is actually the value contained in the TB8 bit of SCON register. Just like mode 1, it has 1 start bit, 1 stop bit, 8 data bits and an additional programmable bit, which is the 9th bit of the 11 bits that are transmitted or received. The bit SMOD in PCON can be used to double the baud rate(by setting it to 1). The baud rate in mode 1 is given by: ((2^ SMOD )/32) * Timer 1 overflow frequency (will be discussed later).

If RB8 = 1 (indicating a valid stop bit), the RI bit of SCON register will be set, and must be cleared by the programmer. During reception of data, the 10th bit i.e the stop bit is stored in RB8. Once data is transmitted successfully, TI bit of SCON register is set automatically and must be cleared by the programmer.

#Uart embedded c program code

Data to be transmitted or received is loaded into SBUF register(See code below). It consists of 1 start bit, 1 stop bit and 8 data bits.

#Uart embedded c program full

Mode 1: It is a 10-bit full duplex mode, i.e transmission and reception can occur simultaneously.

This mode is generally not used for communication between computers or devices. The baud rate in fixed in Mode 0 and is given by oscillator frequency/12. Both transmission and reception are done through RxD line, whereas the TxD line provides the clock for the data transfer.

#Uart embedded c program serial

SCON – Serial Control Register(Bit addressable). Let us see the role of each register one by one. The other registers associated with 8051 UART communication are SBUF, TCON and SMOD bit in PCON register. The number of bits transmitted or received per second(Baud rate) through UART can be obtained by setting the appropriate bits in the SCON register.

In 8051 UART communication, data can be transmitted and received simultaneously which makes it a full duplex communication. The data is serially transmitted through Tx pin and received through the Rx pin. 8051 consists of a programmable serial port with two transmission lines, Rx(receive) and Tx(transmit).