Next Steps:
1. Need an error logger class
2. Need a state variable class
3. Probably should add another UART device


/**
  @page FatFs_uSD_DMA_Standalone  FatFs with uSD card drive application

  @verbatim
  ******************** (C) COPYRIGHT 2019 STMicroelectronics *******************
  * @file    FatFs/FatFs_uSD_DMA_Standalone/readme.txt 
  * @author  MCD Application Team
  * @brief   Description of the FatFs with uSD card drive application
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2019 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under Ultimate Liberty license
  * SLA0044, the "License"; You may not use this file except in compliance with
  * the License. You may obtain a copy of the License at:
  *                             www.st.com/SLA0044
  *
  ******************************************************************************
  @endverbatim

@par Application Description

How to use STM32Cube firmware with FatFs middleware component as a generic FAT
file system module. This example develops an application that exploits FatFs
features to configure a microSD drive.

At the beginning of the main program the HAL_Init() function is called to reset
all the peripherals, initialize the Flash interface and the systick.
Then the SystemClock_Config() function is used to configure the system clock
(SYSCLK) to run at 280 MHz.

The application is based on writing and reading back a text file from a drive,
and it's performed using FatFs APIs to access the FAT volume as described
in the following steps:

 - Link the uSD disk I/O driver;
 - Register the file system object (mount) to the FatFs module for the uSD drive;
 - Create a FAT file system (format) on the uSD drive;
 - Create and Open new text file object with write access;
 - Write data to the text file;
 - Close the open text file;
 - Open text file object with read access;
 - Read back data from the text file;
 - Close the open text file;
 - Check on read data from text file;
 - Unlink the uSD disk I/O driver.

It is worth nothing that the application manages any error occurred during the
access to FAT volume, when using FatFs APIs. Otherwise, user can check if the
written text file is available on the uSD card.

It is possible to fine tune needed FatFs features by modifying defines values
in FatFs configuration file "ffconf.h" available under the project includes
directory, in a way to fit the application requirements.

It is possible to dynamically hot plug/unplug the uSD card, as the application will
handle the plug/unplug events.

@note: for some uSD's, replacing it  while the application is running makes the application
       fail. It is recommended to reset the board using the "Reset button" after replacing
       the uSD.

STM32H7B3I-DK's LED can be used to monitor the application status:
  - LED2 is ON when the application runs successfully.
  - LED3 is ON when any error occurs.
  - LED3 toggle when SD card is unplugged.

@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 needs to ensure that the SysTick time base is always set to 1 millisecond
      to have correct HAL operation.

@Note If the  application is using the DTCM/ITCM memories (@0x20000000/ 0x0000000: not cacheable and only accessible
      by the Cortex M7 and the MDMA), no need for cache maintenance when the Cortex M7 and the MDMA access these RAMs.
      If the application needs to use DMA(or other masters) based access or requires more RAM, then the user has to:
              - Use a non TCM SRAM. (example : CD AXI-SRAM @ 0x24000000)
              - Add a cache maintenance mechanism to ensure the cache coherence between CPU and other masters(DMAs,DMA2D,LTDC,MDMA).
              - The addresses and the size of cacheable buffers (shared between CPU and other masters)
                must be properly defined to be aligned to L1-CACHE line size (32 bytes). 
                
@Note It is recommended to enable the cache and maintain its coherence.
      Depending on the use case it is also possible to configure the cache attributes using the MPU.
      Please refer to the AN4838 “Managing memory protection unit (MPU) in STM32 MCUs”
      Please refer to the AN4839 “Level 1 cache on STM32F7 Series and STM32H7 Series"

@par Keywords

FatFs, SDMMC, SD Card, File system, FAT Volume, Format, Mount, Read, Write,

@par Directory contents

  - FatFs/FatFs_uSD_DMA_Standalone/Core/Inc/stm32h7xx_hal_conf.h               HAL configuration file
  - FatFs/FatFs_uSD_DMA_Standalone/Core/Inc/stm32h7xx_it.h                     Interrupt handlers header file
  - FatFs/FatFs_uSD_DMA_Standalone/Core/Inc/main.h                             Header for main.c module
  - FatFs/FatFs_uSD_DMA_Standalone/Core/Src/stm32h7xx_it.c                     Interrupt handlers
  - FatFs/FatFs_uSD_DMA_Standalone/Core/Src/main.c                             Main program
  - FatFs/FatFs_uSD_DMA_Standalone/Core/Src/system_stm32h7xx.c                 STM32H7xx system source file
  - FatFs/FatFs_uSD_DMA_Standalone/Core/Inc/stm32h7b3i_discovery_conf.h         BSP configuration file    (FatFs)
  - FatFs/FatFs_uSD_DMA_Standalone/FATFS/Target/ffconf.h                       FAT file system module configuration file
  - FatFs/FatFs_uSD_DMA_Standalone/FATFS/Target/sd_diskio.h                    uSD diskio header file
  - FatFs/FatFs_uSD_DMA_Standalone/FATFS/Target/sd_diskio.c                    FatFs uSD diskio driver
  - FatFs/FatFs_uSD_DMA_Standalone/FATFS/App/app_fatfs.h                       Header file for App_fatfs.c file
  - FatFs/FatFs_uSD_DMA_Standalone/FATFS/App/app_fatfs.c                       FatFs application code

@par Hardware and Software environment

  - This application runs on STM32H7B3XXQ devices

  - This application has been tested with STM32H7B3I-DK board and can be
    easily tailored to any other supported device and development board.

@par How to use it ?

In order to make the program work, you must do the following:
 - Insert a microSD card in the board appropriate slot
 - Open your preferred toolchain
 - Rebuild all files and load your image into target memory
 - Run the application

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


 
Pavel A.
 (Community Member)

a day ago
Free running 32-bit HAL timer on STM32H7: something like this:

//~~~~~~~~~~~~~~~~~ TICKLESS HAL TIMER using TIM2 ~~~~~~~~~~~~~~
 
static TIM_HandleTypeDef htim2;
 
extern uint32_t uwTickPrio; /* in hal.c */
extern HAL_TickFreqTypeDef uwTickFreq;
 
#define TIMER2_INPUT_CLK_hz   (200000000UL)  // TIM2 on APB1 @ 200Mhz = 2*HAL_RCC_GetPCLK1Freq()
 
 
static void MX_TIM2_Init(void)
{
    __HAL_RCC_TIM2_CLK_ENABLE();
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
 
  htim2.Instance = TIM2;
  htim2.Init.Prescaler =  TIMER2_INPUT_CLK_hz/1000 - 1;
  htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim2.Init.Period = 0xFFFFFFFFU;
  htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim2) != HAL_OK)
     Error_Handler();
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK)
      Error_Handler();
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
      Error_Handler();
}
 
static inline uint32_t _get_hrtime32()
{
    return htim2.Instance->CNT;
}
 
uint32_t HAL_GetTick(void)
{
    return _get_hrtime32();
}
 
 
void HAL_Delay(uint32_t Delay)
{
  uint32_t tickstart = _get_hrtime32();
  uint32_t wait = Delay;
  if (wait == 0)
  {
      wait = 1;
  }
 
  while ((_get_hrtime32() - tickstart) < wait)
  {
      __NOP();
  }
}
 
 
HAL_StatusTypeDef HAL_InitTick(uint32_t TickPriority)
{
    // NOTE! this can be called twice, because of ST HAL quirks! 
    HAL_NVIC_DisableIRQ(TIM2_IRQn); // interrupt not used
    uwTickPrio = TickPriority;    
    uwTickFreq = HAL_TICK_FREQ_1KHZ; // we simulate 1KHz tick
    MX_TIM2_Init();
    HAL_TIM_Base_Start_IT(&htim2);
    __HAL_TIM_CLEAR_IT(&htim2, TIM_IT_UPDATE); 
    return HAL_OK;
}
 
void HAL_SuspendTick(void)
{
    __BKPT(0); // not implemented
}
 
void HAL_ResumeTick(void)
{
    __BKPT(0); // not implemented
}
 
// HAL time tick interrupt handler
// *** Overrides HAL provided HAL_IncTick()
void HAL_IncTick(void)
{
  __BKPT(0); // must not be called
}
 
 
 