I am working with a generic STM32F103 board.
This board has a serial bootloader on board, that runs on serial port 1. (There are 3 serial ports, numbered 1, 2, and 3). This port is on pins PA9 (tx1) and PA10 (rx1). Naturally the signals are at 3.3 volt levels.
It is not yet clear to me if this loader is in flash or is some permanent part of the chip. It may be possible to install some kind of USB boot loader. This would be more convenient, but would use more of the 64K flash.
To get the bootloader running, you must set the BOOT0 jumper to 1 and the BOOT1 jumper to 0. On my "blue pill" board, the jumper away to the reset buton is "BOOT0". After setting the jumpers the board must be power cycled or reset.
Then you need some USB to serial gadget that uses 3.3 volt levels.
On linux, you need the python loader script:
./ stm32loader.py -p /dev/ttyUSB2 -evw mycode.binHowever, on my Fedora system, I need to first install the python serial module:
dnf install pyserialAfter this, we have some success. I make a symbolic link since I am lazy.
ln -s stm32loader.py loader ./loader -p /dev/ttyUSB1 Bootloader version 0x22 Chip id 0x410, STM32F1, performance, medium-densityIt turns out that the python version has now been replaced by a compiled C loader for one reason or other and that is what you are advised to use:
./stm32ld /dev/ttyUSB1 115200 0 0 Found bootloader version: 2.2 Chip ID: 0410 Skipping flashing ...Note also that in reading the documents from ST about the boot loader, two things are clear. One is that the boot loader resides in "system memory" which does not consume any of flash (and is apparently immutable, so it will be hard to brick one of these units). The other thing is that a USB DFU mode is supported as part of the boot loader in system memory, so making this useful would be a nice step as it would obviate the need for a USB to serial gadget.
dnf install rubygem-serialportWhat I want to do in particular is to read out the present contents of flash (as well as other areas). The C program seems to be tailored just for flashing images. The Python script is more versatile, but still has refused to do the following and read out flash contents. The base address is from the C "stm32ld" program.
tom@trona STM32]$ ./loader -p /dev/ttyUSB1 -a 0x08000000 -l 2048 -r Bootloader version 0x22 Chip id 0x410, STM32F1, performance, medium-density Read 256 bytes at 0x8000000 Traceback (most recent call last): ... blah blah blah __main__.CmdException: Chip replied with a NACK during 0x11Giving all the traceback is lame. If you know there is an error, then report it and exit (traceback is for developers, not end users). Besides that, why does the read from flash fail?
So, I connected this up as follows:
FTDI ground --- ground on edge of STM FTDI 3.3 --- 3.3 on edge of STM FTDI Rx ---- A9 on STM (Tx) FTDI Tx ---- A10 on STM (Rx)Then I plug it in and start playing with the python script.
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