GD32VF103 User Manual
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1.4.
Boot configuration
The GD32VF103 devices provide three kinds of boot sources which can be selected by the
BOOT0 and BOOT1 pins. The details are shown in the following table. The value on the two
pins is latched on the 4th rising edge of CK_SYS after a reset. User can select the required
boot source by set the BOOT0 and BOOT1 pins after a power-on reset or a system reset.
Once the two pins have been sampled, they are free and can be used for other purposes.
Table 1-3. Boot modes
Selected boot source
Boot mode selection pins
Boot1
Boot0
Main Flash Memory
x
0
Boot loader
0
1
On-chip SRAM
1
1
Note:
When the boot source is hoped to be set as
“
Main Flash Memory
”
, the Boot0 pin has
to be connected with GND definitely and can not be floating.
The embedded boot loader is located in the System memory, which is used to reprogram the
Flash memory. In GD32VF103 devices, the boot loader can be activated through the USART0
(PA9 and PA10), USART1 (PD5 and PD6), USBFS in device mode (PA9, PA11 and PA12)
interface.
1.5.
Device electronic signature
The device electronic signature contains memory size information and the 96-bit unique
device ID. It is stored in the information block of the Flash memory. The 96-bit unique device
ID is unique for any device. It can be used as serial numbers, or part of security keys, etc.