This bootloader will install your application by means of the TFTP protocol. There is no need to change your application code. Per default DHCP is used for obtaining the ip-address.
The bootloader is active during reset of the board:
-
Or when the
User Keyis pressed. Which is defined in filelib-gd32/include/board/gd32f207c_eval.h.#define KEY3_PINx GPIO_PIN_14 #define KEY3_GPIOx GPIOB #define KEY3_RCU_GPIOx RCU_GPIOB #define KEY_BOOTLOADER_TFTP_GPIO_PINx KEY3_PINx #define KEY_BOOTLOADER_TFTP_GPIOx KEY3_GPIOx #define KEY_BOOTLOADER_TFTP_RCU_GPIOx KEY3_RCU_GPIOx -
Or when
bkp_data_read(BKP_DATA_1) == 0xA5A5. This is set in your application by means of human readable UDP messages. See for more information: https://www.gd32-dmx.org/bootloader.html. There is also a sample Java UI application available for working with the UDP messages: https://github.com/vanvught/GD32F-Firmware-Update-UI
Otherwise the bootloader will directly jump to you application. With the snippet:
// 8. Call the reset handler
const uint32_t* reset_p = (uint32_t *)(FLASH_BASE + OFFSET_UIMAGE + 4);
asm volatile ("bx %0;" : : "r"(*reset_p));
The bootloader can be installed with the tools supplied by GigaDevice -> http://www.gd32mcu.com/en/download/7?kw=GD32F2
The limitation for the firmware file to be uploaded is given by the RAM available. For example, the MCU on GD32207C-EVAL is the GD32F207VCT6. With the 128K RAM we have the firmware file size limit of 106K.
There are 2 places for this configuration:
File: gd32f207vc_flash.ld
__heap_size = DEFINED(__heap_size) ? __heap_size : 107K;
__stack_size = DEFINED(__stack_size) ? __stack_size : 1K;
File: spiflashinstall.h
# elif defined (BOARD_GD32F207C_EVAL)
# define OFFSET_UIMAGE 0x007000 // 28K
# define FIRMWARE_MAX_SIZE (106 * 1024) // 106K
The 1K difference is needed for other new (malloc) within the bootloader.
The change to be made in your application is in the file gd32f207vc_flash.ld.
MEMORY
{
FLASH (rx) : ORIGIN = 0x08007000, LENGTH = 106K
RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 128K
}
The FLASH ORIGIN must match the OFFSET_UIMAGE from the bootloader file spiflashinstall.h
The direcroty GD32F20x_Demo_Suites_V2.2.1 contains the gd32f20x.bin for each demo. There is also the shell script do-tftp.sh included.
Usage: do-tftp.sh <ip-address>
A ready to compile GD32F20x_Demo_Suites_V2.2.1 can be found here -> https://github.com/vanvught/GD32207C-EVAL-board
The code for the bootloader is a fork from https://github.com/vanvught/rpidmx512. In order to reduce the memory footprint, some functions are not available.