Minimum Baud Rate; Maximum Baud Rate; Bootloader Command Set; Table 3. Bootloader Commands - ST STM32F105 Series Application Note

USART bootloader
microcontroller baud rate can be calculated using the formula below:
STM32Fxxx baud rate Host baud rate
f =
------------------------------------------------------------------------------------------------------- -
B
This baud rate deviation is a nonlinear function depending on the CPU clock and the baud
rate of the host. The maximum of the function (f
due to the smaller baud rate prescale factors, and the implied higher quantization error.
2.3

Minimum baud rate

The lowest tested baud rate (B
timer to overflow. In this event, USARTx would not be correctly initialized.
2.4

Maximum baud rate

B is the highest baud rate for which the deviation still does not exceed the limit. All baud
High
rates between B
The highest tested baud rate (B
2.5

Bootloader command set

The supported commands are listed in
this section.
Table 3.
(2)
Get
Get Version & Read Protection
(2)
Status
(2)
Get ID
Read Memory
Go
Write Memory
Erase
Write Protect
Write Unprotect
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–
STM32Fxxx baud rate
Low
and B are below the deviation limit.
Low High
Bootloader commands
(1)
Command
(3)
(3)
Doc ID 14156 Rev 1
×
100%
) increases with the host baud rate. This is
B
) is 1200. Baud rates below B
) is 115 200.
High
Table 3 below. Each command is further described in
Command
code
Gets the version and the allowed commands
0x00
supported by the current version of the bootloader
Gets the bootloader version and the Read
0x01
Protection status of the Flash memory
0x02 Gets the chip ID
Reads up to 256 bytes of memory starting from an
0x11
address specified by the user
Jumps to an address specified by the user to
0x21
execute (a loaded) code
Writes up to 256 bytes to the RAM or Flash memory
0x31
starting from an address specified by the user
0x43 Erases from one to all the Flash memory pages
0x63 Enables the write protection for some sectors
Disables the write protection for all Flash memory
0x73
sectors
≤ 2.5%.
, where f
B
would cause the SysTick
Low
Command description
AN2662