Which registers are used to check the status of receiver and transmitter in UART?
Bit 0 in the LSR line status register can be used to check if all received bytes have been read. This bit will change to zero if no more bytes are present. The THR, transmitter holding register is used to buffer outgoing characters. If no FIFO buffering is used, only one character can be stored.
What is UART buffer?
A buffer is an area of memory in the UART in which to store incoming data. It allows data to be stored physically in the UART which can later be serviced by a software driver.
How many devices can be connected to UART?
The UART protocol typically allows for only two devices to be connected to each other. There is no easy way of connecting multiple UART devices to a single interface.
Why FIFO is used in UART?
A FIFO (First In First Out) is a UART buffer that forces each byte of your serial communication to be passed on in the order received. This means that the UART will issue an interrupt to the system for each byte of data received, which uses a lot of CPU resources.
How fast can we run a UART?
UART interfaces have a maximum data rate of around 5 Mbps. There is also some protocol overhead in the form of start, stop, and parity bits. The data rate of a UART interface is similar to that of an I2C interface.
How to know if UART TX or rx interrupt has occurred?
You might need to read the UARTxIIR register to know whether the interrupt has occured because of “TX buffer empty” or “RX buffer full” condition. Please make sure that the required interrupt is enabled in the UARTxIER register.
When is an interrupt generated in STM32 UART?
An interrupt is generated if the RXNEIE bit is set. In multibuffer, RXNE is set after every byte received and is cleared by the DMA read to the Data Register. In single buffer mode, clearing the RXNE bit is performed by software read to the USART_DR register.
How to use UART in SHARC 21369 processor?
I am suing SHARC 21369 processor. I want to use the UART Transmit and receive interrupt to send and receive messages. I have gone through the UART echo back example. The echo back example uses only receive interrupt.
When to enable or disable the TX interrupt?
When implemented in a proper way: Enable the TX interrupt. The user code starts transmission by sending only the first byte in the buffer. At the end of TX (of the first byte), an interrupt will be generated.