/**
  @page TIM_DMABurst TIM_DMABurst example started by Linux Remote Processor Framework

  @verbatim
  ******************** (C) COPYRIGHT 2019 STMicroelectronics *******************
  * @file    TIM/TIM_DMABurst/Remoteproc/README
  * @author  MCD Application Team
  * @brief   How to run example using Linux Remote Processor Framework
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2019 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under BSD 3-Clause license,
  * the "License"; You may not use this file except in compliance with the
  * License. You may obtain a copy of the License at:
  *                        opensource.org/licenses/BSD-3-Clause
  *
  ******************************************************************************
  @endverbatim

@par Description of M4 Cube example with Linux Remote Processor Framework

When Cube firmware is running on Cortex-M4, System Clock tree and regulators(vrefbuf) are configured by Cortex-A7
Besides, clock source for each peripheral assigned to Cortex-M4 is done by Cortex-A7.


@par How to use it ?

In order to make the program work with Linux running on Cortex-A7, you must do the following :
Before running M4 Cube example, you have to
1) interrupt uboot
2) choose the right configuration to make sure that M4 resources are assigned to Linux Resource Manager driver

Then,
 - Start example using the following command: "fw_cortex_m4.sh start" under example directory installed in userfs partition
     * it will load and start firmware using Linux Remote Processor
 - Stop example using the following command: "fw_cortex_m4.sh stop" under example directory installed in userfs partition
     * it will stop firmware using Linux Remote Processor

@par Example Description
This example shows how to update the TIMER channel1 period and the duty cycle 
using the TIMER 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 (if supported), 0x0555 will be transferred into CCR1. 

The TIM1CLK frequency is set to SystemCoreClock, to get TIM1 counter
clock at 16 MHz the Prescaler is computed as following:
- Prescaler = (TIM1CLK / TIM1 counter clock) - 1

The TIM1 Frequency = TIM1 counter clock/(ARR + 1)
                   = 16 MHz / 4096 = 3.9 KHz

The TIM1 CCR1 register value is equal to 0x555, so the TIM1 Channel 1 generates a 
PWM signal with a frequency equal to 3.9 KHz and a duty cycle equal to 33.33%:
TIM1 Channel1 duty cycle = (TIM1_CCR1/ TIM1_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 This example needs to ensure that the SysTick time base is always set to 1 millisecond
      to have correct HAL operation.

@par Directory contents  

  - TIM/TIM_DMABurst/Inc/stm32mp1xx_hal_conf.h    HAL configuration file
  - TIM/TIM_DMABurst/Inc/stm32mp1xx_it.h          Interrupt handlers header file
  - TIM/TIM_DMABurst/Inc/main.h                  Header for main.c module  
  - TIM/TIM_DMABurst/Src/stm32mp1xx_it.c          Interrupt handlers
  - TIM/TIM_DMABurst/Src/main.c                  Main program
  - TIM/TIM_DMABurst/Src/stm32mp1xx_hal_msp.c     HAL MSP file
  - TIM/TIM_DMABurst/Src/system_stm32mp1xx.c      STM32MP1xx system source file

@par Hardware and Software environment

  - This example runs on STM32MP157CACx devices.
  - At the beginning of the main program the HAL_Init() function is called to reset all the peripherals, initialize the systick.
    Then the System clock source is configured by the SystemClock_Config() function in case of Engineering Mode, 
    this clock configuration is done by the Firmware running on the Cortex-A7 in case of Production Mode.
    
  - This example has been tested with STMicroelectronics STM32MP157C-DK2 
    board and can be easily tailored to any other supported device 
    and development board.

  - STM32MP157C-DK2 Set-up
    - Connect the TIM1 output channel to an oscilloscope to monitor the different waveforms: 
    - TIM1 TIM_CHANNEL_1 (PE.09 (pin 7 in CN14 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

 * <h3><center>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */
