SPMA085 June   2022 TM4C1230C3PM , TM4C1230C3PM , TM4C1230D5PM , TM4C1230D5PM , TM4C1230E6PM , TM4C1230E6PM , TM4C1230H6PM , TM4C1230H6PM , TM4C1231C3PM , TM4C1231C3PM , TM4C1231D5PM , TM4C1231D5PM , TM4C1231D5PZ , TM4C1231D5PZ , TM4C1231E6PM , TM4C1231E6PM , TM4C1231E6PZ , TM4C1231E6PZ , TM4C1231H6PGE , TM4C1231H6PGE , TM4C1231H6PM , TM4C1231H6PM , TM4C1231H6PZ , TM4C1231H6PZ , TM4C1232C3PM , TM4C1232C3PM , TM4C1232D5PM , TM4C1232D5PM , TM4C1232E6PM , TM4C1232E6PM , TM4C1232H6PM , TM4C1232H6PM , TM4C1233C3PM , TM4C1233C3PM , TM4C1233D5PM , TM4C1233D5PM , TM4C1233D5PZ , TM4C1233D5PZ , TM4C1233E6PM , TM4C1233E6PM , TM4C1233E6PZ , TM4C1233E6PZ , TM4C1233H6PGE , TM4C1233H6PGE , TM4C1233H6PM , TM4C1233H6PM , TM4C1233H6PZ , TM4C1233H6PZ , TM4C1236D5PM , TM4C1236D5PM , TM4C1236E6PM , TM4C1236E6PM , TM4C1236H6PM , TM4C1236H6PM , TM4C1237D5PM , TM4C1237D5PM , TM4C1237D5PZ , TM4C1237D5PZ , TM4C1237E6PM , TM4C1237E6PM , TM4C1237E6PZ , TM4C1237E6PZ , TM4C1237H6PGE , TM4C1237H6PGE , TM4C1237H6PM , TM4C1237H6PM , TM4C1237H6PZ , TM4C1237H6PZ , TM4C123AE6PM , TM4C123AE6PM , TM4C123AH6PM , TM4C123AH6PM , TM4C123BE6PM , TM4C123BE6PM , TM4C123BE6PZ , TM4C123BE6PZ , TM4C123BH6PGE , TM4C123BH6PGE , TM4C123BH6PM , TM4C123BH6PM , TM4C123BH6PZ , TM4C123BH6PZ , TM4C123FE6PM , TM4C123FE6PM , TM4C123FH6PM , TM4C123FH6PM , TM4C123GE6PM , TM4C123GE6PM , TM4C123GE6PZ , TM4C123GE6PZ , TM4C123GH6PGE , TM4C123GH6PGE , TM4C123GH6PM , TM4C123GH6PM , TM4C123GH6PZ , TM4C123GH6PZ , TM4C123GH6ZXR , TM4C123GH6ZXR , TM4C1290NCPDT , TM4C1290NCPDT , TM4C1290NCZAD , TM4C1290NCZAD , TM4C1292NCPDT , TM4C1292NCPDT , TM4C1292NCZAD , TM4C1292NCZAD , TM4C1294KCPDT , TM4C1294KCPDT , TM4C1294NCPDT , TM4C1294NCPDT , TM4C1294NCZAD , TM4C1294NCZAD , TM4C1297NCZAD , TM4C1297NCZAD , TM4C1299KCZAD , TM4C1299KCZAD , TM4C1299NCZAD , TM4C1299NCZAD , TM4C129CNCPDT , TM4C129CNCPDT , TM4C129CNCZAD , TM4C129CNCZAD , TM4C129DNCPDT , TM4C129DNCPDT , TM4C129DNCZAD , TM4C129DNCZAD , TM4C129EKCPDT , TM4C129EKCPDT , TM4C129ENCPDT , TM4C129ENCPDT , TM4C129ENCZAD , TM4C129ENCZAD , TM4C129LNCZAD , TM4C129LNCZAD , TM4C129XKCZAD , TM4C129XKCZAD , TM4C129XNCZAD , TM4C129XNCZAD

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2How to Install
    1. 2.1 Update the FreeRTOS Version in the TivaWare Directory
    2. 2.2 Adding FreeRTOS Hardware Driver Files for TM4C LaunchPads
  5. 3Architecture for TM4C FreeRTOS Examples
    1. 3.1 Proper Clock Configuration
    2. 3.2 How to use Hardware Interrupts Alongside the FreeRTOS Kernel
  6. 4Example Project Walkthroughs
    1. 4.1 Download and Import the Examples
    2. 4.2 Kernel Examples
      1. 4.2.1 Example: hello
      2. 4.2.2 Example: notify_example
      3. 4.2.3 Example: queue_example
      4. 4.2.4 Example: semaphore_example
      5. 4.2.5 Example: blinky_queue
      6. 4.2.6 Software Timer Examples
        1. 4.2.6.1 Example: timer_sw_oneshot
        2. 4.2.6.2 Example: timer_sw_periodic
        3. 4.2.6.3 Example: timer_sw_led_counter/timer_sw_rgb
    3. 4.3 ADC Examples
      1. 4.3.1 Example: adc_multi_channel
      2. 4.3.2 Example: adc_timer_trigger
    4. 4.4 Hardware Timer Examples
      1. 4.4.1 Example: timer_hw_oneshot
      2. 4.4.2 Example: timer_hw_periodic
      3. 4.4.3 Example: timer_hw_pwm
    5. 4.5 UART Example
      1. 4.5.1 Example: uart_thread_safe
    6. 4.6 Watchdog Example
      1. 4.6.1 Example: watchdog

4.5 UART Example

UART is a popular asynchronous serial communication interface that is frequently used to send data between different processors or from hardware to a computer. For example, each TM4C LaunchPad has a UART to USB bridge that can be connected to a terminal / console to receive data from the UART0 port of the TM4C microcontroller. This is often used with example projects to indicate configurations, output data, or provided status updates. For developers, this can be used to output real-time debug information as well.

While UART is a very simple and easy to use serial communication method, one drawback can be the slow speeds to transfer data. Baud rates are typically set at most to be 115,200 which equates to effectively 11.5kBytes/sec. Because of this slower communication, it can take longer than expected to output a string of text. This is why even for bare metal applications, it is not recommended to output full strings of UART data within an ISR. For a system running an RTOS, the UART interface needs to be properly managed so that it is not being accessed by multiple resources at once because otherwise the output could become corrupted if the last message sent takes longer to output than the user anticipates.