Stm32f4硬體週邊介紹
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This document provides an overview of GPIO and interrupt functionality on the STM32F407 microcontroller. It describes how to configure GPIO pins for input, output, and alternate functions. It explains how to set the pin speed, mode, type, and pull-up/pull-down resistors. The document also covers interrupt handling, including the nested vector interrupt controller (NVIC) and external interrupt controller (EXTI). Code examples are provided for setting up GPIO pins and configuring interrupts.
Stm32f4硬體週邊介紹
- 1. 超威猛應⽤用輔具特⼯工隊! STM32F407 硬體週邊介 紹 ⺩王尹⾠辰(JackABK) 2014/09/04 abkabkabkyes@gmail.com
- 2. GPIO
- 3. GPIO(General Purpose Input/Output) • GPIO is a generic pin on a chip whose behavior ! including whether it is an input or output pin) can be controlled (programmed) by the user at run time.
- 4. GPIO Input • Floating unknown voltage input stage • Pull-up connect to high voltage • Pull-down connected to ground
- 6. GPIO Output • push pull pull-up pull-down • open-drain pull-up pull-downPull-down
- 8. Setting GPIO pins • You can configure on the corresponding peripheral: Speed Mode Type Pull up/pull down resistors
- 9. Setting GPIO pins • On the STM32F4xx the GPIO ports are connected to the AHB1 bus • Enabling the clock:
- 10. Setting GPIO pins • The GPIO’s clock can be anything of the following: • GPIO_Speed_2MHz GPIO_Speed_25MHz GPIO_Speed_50MHz GPIO_Speed_100MHz
- 11. Setting GPIO pins • On the STM32F4 the GPIO can have up to 4 modes GPIO_Mode_OUT for digital output GPIO_Mode_IN for digital input GPIO_Mode_AN for analog input GPIO_Mode_AF for the alternate functions (like SPI, I²C, USART, …)
- 12. Setting GPIO pins • For the gpio output, The type indicates the hardware configuration of the pin which can be: GPIO_OType_PP, ! • a push-pull is driving the output GPIO_OType_OD! • the output is open-drain
- 13. Setting GPIO pins •Next we can configure pull up, pull down resistors or nothing at all for each pin:! •GPIO_PuPd_NOPULL no resistor connected •GPIO_PuPd_UP pin is connected to a pull up resistor •GPIO_PuPd_DOWN pin is connect to a pull down resistor
- 14. Setting GPIO pins The resistors value of Pull-up and Pull-down
- 15. Setting GPIO pins •A complete of code to set the gpio pin:
- 16. Interrupt
- 19. Interrupt handler • On way to achieve this goal consists in the creation of tasks waiting for an interrupt to occur with a semaphore. ! • Let this safer portion of code actually handle the interrupt. An ISR “gives” a semaphore and unblock a ’Handler” task that is able to handler the ISR, making the ISR execution much shorter
- 20. Nested Vectored Interrupt Controller (NVIC) • Depending on the implementation used by the silicon manufacturer. • The NVIC can support up to 240 external interrupts with up to 256 different priority levels(0 to 255) that can be dynamically reprioritized. PreemptionPriority: 4bits SubPriority: 4bits
- 21. External Interrupt(EXTI) •Before settings EXTI, You must be: connected from GPIO settings EXTI 設定哪條Line • Interrupt mode • interrupt condition?(Rising, Falling, Rising&falling ) • LineCmd( ENABLE is open，DISABLE is close.) settings NVIC • IRQ_Channel • PreemptionPriority and SubPriority • ChannelCmd
- 23. External Interrupt(EXTI) The hardware of controller EXTI (blue boxes are registers, red dots are input pins)
- 24. External Interrupt(EXTI) for example
- 25. Ref. ! • STM32F4 GPIO Configuration • NCKU wiki • Interrupts & ports
- 26. Thanks!