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 , TM4C123BH6ZRB , TM4C123BH6ZRB , TM4C123FE6PM , TM4C123FE6PM , TM4C123FH6PM , TM4C123FH6PM , TM4C123GE6PM , TM4C123GE6PM , TM4C123GE6PZ , TM4C123GE6PZ , TM4C123GH6PGE , TM4C123GH6PGE , TM4C123GH6PM , TM4C123GH6PM , TM4C123GH6PZ , TM4C123GH6PZ , TM4C123GH6ZRB , TM4C123GH6ZRB , 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

4.2.6 Software Timer Examples

Timers are an important feature for microcontroller as they are often used to schedule the execution of a function at a set time in the future or with a fixed frequency periodically. For this reason, almost all embedded micrcontrollers have built-in hardware timers. FreeRTOS, as part of the kernel, provides software timers that are similar in nature to the hardware timers but do not require built-in support. These software timers are not plugged into any hardware timers, instead they are sourced from the RTOS tick and fully controlled by the kernel. When a software timer expires, it executes a specified callback function. A software timer callback function should involve simple code processing to it can execute without any loops or delays. It can be assigned priority levels as needed. Because the callback is triggered each time the timer expires, it is essential that a callback function must never call FreeRTOS API functions that will result in the callback function in a BLOCKed state.