STM32CubeF4

@verbatim
******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
* @file TIM/TIM_DMABurst/readme.txt
* @author MCD Application Team
* @brief Description of the TIM DMA Burst example.
******************************************************************************
* @attention
*
* Copyright (c) 2017 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
@endverbatim

@par Example Description

This example shows how to update the TIM1 channel1 period and the duty cycle
using the TIM1 DMA burst feature.

Every update DMA request, the DMA will do 3 transfers of half words into Timer
registers beginning from ARR register.
On the DMA update request, 0x0FFF will be transferred into ARR, 0x0000
will be transferred into RCR, 0x0555 will be transferred into CCR1.

The TIM2CLK frequency is set to (SystemCoreClock/2), to get TIM2 counter
clock at 18 MHz the Prescaler is computed as following:
- Prescaler = (TIM2CLK / TIM2 counter clock) - 1

SystemCoreClock is set to 180 MHz.

The TIM2 Frequency = TIM2 counter clock/(ARR + 1)
= 18 MHz / 4096 = 4.39 KHz

The TIM2 CCR1 register value is equal to 0x555, so the TIM2 Channel 1 generates a
PWM signal with a frequency equal to 4.39 KHz and a duty cycle equal to 33.33%:
TIM2 Channel1 duty cycle = (TIM2_CCR1/ TIM2_ARR + 1)* 100 = 33.33%

The PWM waveform can be displayed using an oscilloscope.

@note Care must be taken when using HAL_Delay(), this function provides accurate
delay (in milliseconds) based on variable incremented in SysTick ISR. This
implies that if HAL_Delay() is called from a peripheral ISR process, then
the SysTick interrupt must have higher priority (numerically lower)
than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.

@note The application need to ensure that the SysTick time base is always set to 1 millisecond
to have correct HAL operation.

@note The connection of the LCD reset pin to a dedicated GPIO PK7 instead of the STM32F469 NRST pin may cause residual display on LCD with applications/examples that do not require display.
The LCD clear can be ensured by hardware through the boards power off/power on or by software calling the BSP_LCD_Reset() function.

@par Keywords

Timers, DMA, Burst mode, Duty Cycle, Waveform, Oscilloscope, Output, Signal, PWM

@par Directory contents

- TIM/TIM_DMABurst/Inc/stm32f4xx_hal_conf.h HAL configuration file
- TIM/TIM_DMABurst/Inc/stm32f4xx_it.h Interrupt handlers header file
- TIM/TIM_DMABurst/Inc/main.h Header for main.c module
- TIM/TIM_DMABurst/Src/stm32f4xx_it.c Interrupt handlers
- TIM/TIM_DMABurst/Src/main.c Main program
- TIM/TIM_DMABurst/Src/stm32f4xx_hal_msp.c HAL MSP file
- TIM/TIM_DMABurst/Src/system_stm32f4xx.c STM32F4xx system source file

@par Hardware and Software environment

- This example runs on STM32F469xx/STM32F479xx devices.
- In this example, the clock is set to 180 MHz.

- This example has been tested and validated with STMicroelectronics STM32469I-EVAL RevC
board and can be easily tailored to any other supported device
and development board.

- STM32469I-EVAL Set-up
- Connect the TIM2 output channel to an oscilloscope to monitor the different waveforms:
- TIM2 CH1 (PA.00 (pin 15 in CN5 connector))

@par How to use it ?

In order to make the program work, you must do the following :
- Open your preferred toolchain
- Rebuild all files and load your image into target memory
- Run the example