Post updated with new screens and up-to-date information ! There have been several requests from users to explain more about loading programs into the flash memory of STM32 microcontrollers. There are several ways on how to perform stm32 flash programming. Any of these methods are great if they get the job done.
In this topic, let us focus on how to perform STM32 flashing by using a bootloader. Today probably, no manufacturer is producing developing boards with RS interface.
Nevertheless, you like me, probably have a dozen older boards with a serial port.
Developing OpenOCD FLASH drivers for External Memories
They are great boards still to use in many projects. The main features of the processor:. Probably you have a newer computer which may not have a serial interface. There are two ways of solving this problem.
Check your motherboard if it has a serial interface connector. This way you can get a cheap external expansion connector, which connects, to the motherboard. You can get them on Amazon for cheap.
Most of USB to serial cables are recognized automatically by operating systems, and no additional actions are needed. There may be some weird cables with unrecognized converter chips. This way you will need a driver from the manufacturer.
The best advice is to stay away from suspicious cheap cables and use known brands. All the STM32 microcontrollers come with built-in bootloaders that burned in during production.
Mostly we are dealing with low, medium, and high-density devices so they can access bootloader using USART1 interface. To enter the bootloader, a couple of special MCU pins has to be set-up to proper logical values.
Boot pins can select several modes of bootloader operation:. Let us focus on the second case — System memory. In the image above, you can see that the jumper setting already selects to run internal bootloader after the savage msr 15 upper receiver. Be sure to get the latest version to have proper support for the newest operating systems like Windows Install it and launch. Be sure to select correct COM port:.
Connect the board to PC using your preferred cable and hit the Reset button before further actions. After you click the Next button, the next screen opens. It confirms that you successfully entered the bootloader. The flash loader detects the flash size of the device, which, in my case, is KB. Hit the Next to proceed to the device selection screen. As you can see, the target device is highlighted automatically.Cookie Notice. Cookies and similar technologies enable us to provide you with an optimized user experience and functionality of our website.
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Since a bit ECC code is associated to each bit data Flash word, only write. It's more optimized. Thank you for explanation and fast response.
I agree that writing a byte is possible, but not in a manner as in an example below.Getting started with STM32F746 discovery kit
I'm very sorry to keep nagging with this topic, but we're migrating a project from the STM32F2 where such an operation was possible we've used the described method to 'update' a checksum in the beginning of a FLASH sector after all data was successfully written. It is not recommended to overwrite a not virgin Flash word. The result may result in an.
Also each S-record line have a starting address in 32 byte blocks. Depending on the linker file definition, sometimes I get a different staring address e. To simulate this matter made a small application trying to understand the behavior of the H All seems to be ok. The reading of the flash bit-section cannot be performed by the debugger.
Most likely due to ECC and faulting. When processing sparse or unaligned hex files you really need to cache the data in larger blocks, and flush the data as aligned lines into the Flash array, and finally once you've encountered the terminal record. Either your S-Record processing needs to get smarter and handle multiple lines so it can fold into single aligned writes, or you work with packaged binary data, and use something like X-Modem with larger and aligned blocks. When setting a breakpoint I can see in the debugger that effectively the flash is not empty:.
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It only takes a minute to sign up. I am writing data to the internal flash of a STM32F and I'm wondering what the difference between pages and sectors is? And what is the purpose of using sectors instead? Notice that I'm very new and the reason to why I'm asking is because I have previously written to flash knowing the page size and amount of pages.
But now I have 8 sectors instead. Unless I have missed it somewhere I can't find any reference to pages or page size in any any document to the STM32F The concept is the same, between page and sectors. STM32F7 documentation uses the sector term because they are much bigger than the typical pages in external flash memory. But it doesn't matter.
So, you can't find reference to pages because what you called pages are here called sectors. The constraint is: when you want to erase, you have to erase the whole sector. As you have seen, on STM32F7, there are 8 sectors, with different sizes 4 sectors of 32 Kbytes, 1 sector of Kbytes, and 3 sectors of Kbytes. The fact they have different sizes allow you to have more flexibility in the way you organize your flash.
For example, you could have a sector reserved for configuration data. This way, when you want to reprogram this part, you don't have to erase the whole firmware code. But you still have to erase the whole configuration sector, even if you need to change just a single byte of it.
And it is true these sectors are huge, so you can't use this flash as easily as typical external serial flashes on which you could organize things in a more flexible way or even use a filesystem. But this is not the purpose of these embedded flash memories.
If you need a more flexible way to store persistent data that can change over time, use an external flash, or external EEPROM, depending on you constraints. There is, however, a trick you could use on the main MCU flash: the erase is required only when you switch bits from 0 to 1. To switch bits from 1 to 0, you just need to program the flash bytes see the note in chapter 3. Programming the flash bytes can be made as many times as you want on the sector, and can be made on individual bytes.
So you could take advantage of this by dividing the huge "configuration" sector in small chunks that you program individually, when your data changes. Then, you need an index in which you "fuse" the bits from 1 to 0 to know in which chunk the latest data can be found.
Finally, when all the chunks have been used, you erase the whole sector and start over. This wastes a lot of space, but may give you the flexibility you need without compromising too much on flash endurance. Sign up to join this community.The following power supply configuration should be used:. The following picture illustrates the hardware set-up:. The procedure described here explains how to install the bootable Linux image usbflash.
Here is how you can build and install the bootable Linux image from the project sources usbflash. Contact Emcraft to obtain the bootable image and project source files. Note: The Linux image and the sample project have been built and validated in context of the Emcraft Systems Release 1.
RPC: Registered tcp transport module. JFFS2 version 2. Block layer SCSI generic bsg driver version 0.
Flashing programs to STM32. Embedded Bootloader
At this point, the USB Flash is accessible as a disk. The following command is used to examine the disk, which is detected as a 4GBytes disk partitioned to have a single empty FAT32 partition:.
Let's mount the FAT32 file system. As expected, it is empty at this point:.
Let's "harvest" some data and store what is collected into a file on the USB Flash disk. In this demo, we emulate a data stream by taking a snapshot of the system time each second:. Note that the format of Windows and Unix text files differs slightly.There is something I do not understand so please let me ask a question. Before writing, is it necessary to "read two bytes anywhere on the flash and write the same data to the same place"?
I write and don't stick to the address. Is there any previous setting?
Internal flash write using HAL function
No, this seems to be a totally unnecessary step. You think this why? Writing to 0x is something you'd want to avoid. You'd want to clear any pending errors. Erasing blocks you are currently executing from will likely crash the system. Both Erase and Write are self timing, functions return when complete or on failure, check the status returned.
The CPU will block if you execute code from the same flash bank you are erasing or writing. This will also limit realtime responsiveness of interrupts, etc. If this is important run code from RAM, with vector table there too. To speed things up you might want to read the memory words to a ensure they are blank, b already contain the data you plan on writing. You would have to be really sure that the meaning of "the part where" is exactly the same to you on one hand, and the flash programming unit on the other.
Odds are they're not. Just because you're not literally erasing the very branch of the code you're currently executing from under youreself, that doesn't mean that particular region is available for code to run in while an erase is in progress. View all questions in Keil forum.
Site Search User. Software Tools.If you want to place some code or data in your project into an external FLASH memory and access it from your code as if it was located in the normal FLASH memory, you need to do the following:. This tutorial focuses on developing the FLASH driver; more information on configuring the project can be found in this tutorial. May 11, armstm If you want to place some code or data in your project into an external FLASH memory and access it from your code as if it was located in the normal FLASH memory, you need to do the following: Add the external memory via External Memories page of VisualGDB Project Properties Actually setup the memory mapping from your startup code so that the memory contents is accessible to your program Develop a FLASH driver that will automatically program the external memory when you start debugging your project This tutorial focuses on developing the FLASH driver; more information on configuring the project can be found in this tutorial.
Instead of configuring the driver, add the following lines to the main source file and start debugging the project as is:. InterruptEnabler enabler .The STM32 series are some of the most popular microcontrollers used in a wide variety of products.
They also have an excellent support base from multiple microcontroller development forums. STM32 microcontrollers offer a large number of serial and parallel communication peripherals which can be interfaced with all kinds of electronic components including sensors, displays, cameras, motors, etc. The range of performance available with the STM32 is quite expansive. At the other performance extreme, the STM32H7 operates at up to MHz, and is available in packages with as many as pins.
The more advanced models are available with Floating Point Units FPU for applications with serious numerical processing requirements. These more advanced models blur the line between a microcontroller and a microprocessor. Finally, the STM32L sub-series is designed specifically for low-power portable applications running from a small battery.
The development tools include:. There are several software development tools available for code development on STM32 microcontrollers. The software tools are available as Integrated Development Environments IDE which combines all of the necessary tools into an integrated environment. Then, add the code that is required for the specific application and model of microcontroller. It also can be used to configure the peripherals on the multiplexed pins of the microcontroller.
The following section describes in detail how to create a simple UART application for the STM32F microcontroller that echoes whatever is typed on a terminal window.
The user code must be written within these comment blocks. Whenever the code is re-generated with modified configurations the STMCube tool retains the user code within these user comment blocks.
After all of the initialization code, enable the driver to receive 1 byte. The following function enables the RXNE interrupt bit. The ST-Link debugger will be selected by default. The microcontroller will now echo any data received over the UART. Now anything that is sent from the terminal will echo back through the microcontroller. The exception and the interrupt vector table for this family of MCUs is given in the table below. For the external interrupt lines, to generate an interrupt, the interrupt line should be configured and enabled.