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A short class with Sarah and her students. The other ways are under More.
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Today we're going to learn about UART, which stands for Universal Asynchronous Receiver-Transmitter. It's essential for serial communication. Does anyone know what serial communication is?
Is it a way for microcontrollers to talk to each other or to devices?
Exactly! UART allows for the transmission of data between devices asynchronously, which means that the data can be sent and received without a synchronized clock signal. This is really useful in many applications. Now, who can tell me what the baud rate is?
Isn't the baud rate the speed of the communication?
Correct! The baud rate indicates how many signals are sent per second. For example, we often set a baud rate of 9600 for UART communication. Let's remember 'Baud = speed', that's a handy mnemonic! Now let's dive into how we configure UART in ARM CMSIS.
To configure the UART peripheral, we use a few key commands. For example, we set the baud rate with USART2->BRR = 0x8B;. Can anyone guess what this hexadecimal value indicates?
I think it's the specific baud rate we want to use, right?
Exactly! This value corresponds to the baud rate of 9600. After setting the baud rate, we need to enable the USART by using USART2->CR1 |= USART_CR1_UE;. Can anyone tell me why this step is necessary?
If we don't enable it, nothing will happen, and we won't be able to send or receive any data!
Right again! Finally, we also have to enable the transmit functionality with USART2->CR1 |= USART_CR1_TE;. Congratulations! You’re all grasping this quite well!
Now that we have configured UART, let’s look at how to transmit data. For example, to send a character we use the function uart_send_char(). Who can explain what this function does?
I think it waits for the transmit buffer to be empty before sending the character?
That’s correct! It ensures we only send data when the transmitter is ready. So we check if USART2->SR & USART_SR_TXE is true – that means it’s safe to send the next character. What do we do after that?
We assign the character to USART2->DR, then it gets sent, right?
Yes, well done! This method makes it simple to transmit data character by character. It’s also how we send strings through the uart_send_string() function. Now let's summarize what we learned.
In summary, we explored how the UART in ARM CMSIS is used for serial communication. We covered baud rates, enabling the USART, and how to send data. Remember, 'UART is our Universal Translator' for communication between microcontrollers and other devices!
A hardware interface for asynchronous serial communication.
A measurement of the speed of data transmission, critical for ensuring both ends of communication operate correctly.
Essential step to allow the microcontroller to send and receive data.
For UART to smartly chart, set the baud rate from the start!
Imagine UART as a speak-and-listen duo, it waits patiently for its turn before sending messages.
Setup UART: One - Set baud rate, Two - Enable USART, Three - Start transmitting!
UART: Use Asynchronous Ready Transmit
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What is UART?
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How do you set the baud rate?
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Why check transmit buffer?
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Universal Asynchronous Receiver-Transmitter; a hardware communication protocol used for serial communication.
The speed of data transmission in bits per second.
Universal Synchronous/Asynchronous Receiver-Transmitter, which is a type of UART that can operate synchronously or asynchronously.
Data Register; holds the data to be transmitted via UART.
Status Register; indicates the current status of the UART, including whether it is ready to transmit data.
This section provides an overview of how to use the UART peripheral in ARM CMSIS for serial communication.
The UART section explains how ARM CMSIS facilitates the initialization and configuration of the Universal Asynchronous Receiver-Transmitter (UART), including setting baud rates and handling interrupts, crucial for establishing serial communication in embedded systems.
The Universal Asynchronous Receiver-Transmitter (UART) is a critical peripheral for serial communication in embedded systems. ARM CMSIS provides a set of functions that simplify the initialization and usage of UART within ARM Cortex-M microcontrollers. This section highlights the key functions that facilitate minimal configuration, including setting baud rates, data bits, stop bits, and managing interrupts.
Key Concepts:
USART2->BRR = 0x8B; sets the baud rate to 9600.USART2->CR1 |= USART_CR1_UE; enables the USART interface.USART2->CR1 |= USART_CR1_TE;, we allow the USART to transmit data.These fundamental configurations allow for smooth communication between microcontrollers and other devices, making UART a popular choice in embedded development.