Beginning STM32: Developing with FreeRTOS, libopencm3 and GCC

© Warren Gay 2018

Warren GayBeginning STM32https://doi.org/10.1007/978-1-4842-3624-6_22

Answers to Exercises

Warren Gay¹ 

(1)

St. Catharines, Ontario, Canada

 

Chapter 4

1. 1.

   What GPIO port does the built-in LED on the Blue Pill PCB use? Specify the libopencm3 macro name for the port.

   Answer: PORTC

    
2. 2.

   What GPIO pin does the built-in LED on the Blue Pill PCB use? Specify the libopencm3 macro name.

   Answer: GPIO13

    
3. 3.

   What level is required to turn the built-in LED on for the Blue Pill PCB?

   Answer: logic low (or zero volts)

    
4. 4.

   What are two factors affecting the chosen loop count in a programmed delay in non-multitasking environments?

   Answer:

   1. a.

      The CPU clock rate

       
   2. b.

      Instruction execution time

       
    
5. 5.

   Why are programmed delays not used in a multi-tasking environment?

   Answer: ...