OLIMEX© 2015
STM32-P405 user's manual
6.9 Extension pins and prototype area
At the right side of the board are is a column of pins. Each of them is connected to a signal – the name of
the signal available at a pin is printed next to it. Each of these extension pins carry the same signal as the
row of pinholes next to it. This prototype area provides very nice GPIO option – you can interface the
signals exposed with your breadboarding wires; you can use them as headers; you can take signal
readings; etc.
The distance between two adjacent pinholes is 0.1''.
Refer to sub-chapter “2.3 Prototype area pinout (top view)” for visual representation of each pin near the
connectors.
6.4 Jumper description
Please note that all of the jumpers on the board are SMD type. If you feel insecure in your
soldering/cutting technique it is better not to adjust the SMD jumpers.
6.4.1 BOOT memory select jumpers
B1_H/B1_L and B0_H/B0_L are SMD jumpers which define the initial boot default priority of the
microcontroller (aka which memory to boot from). By default they are set so that the board would boot
from the user Flash memory.
Notice that these two jumpers must be moved together – they are responsible for the boot mode if
bootloader is present. The board can search for bootloader on three places – either the user Flash memory,
the System memory, or the Embedded SRAM.
By default, B0_H/B0_L is set to position B0_L; the other jumper B1_H/B1_L is set to B1_L – in this
configuration the board will try to boot from user Flash memory.
To boot from the system memory you need to change the position of B0_H/B0_L jumper to position
B0_H. The boot loader is located in system memory (if you want to program the board via the USB and
DFUse software – use this mode).
Changing both high positions (B0_H/B0_L to B0_H; and B1_H/B1_L to B1_H) would attempt to boot
from the Embedded SRAM.
Refer to the “STM32 microcontroller system memory boot mode” document (“AN2606”) for more
information about the bootloader available on STM32F4xx microcontrollers.
6.4.2 RTS_E
Closing this jumper enables RTS line on the RS232_2 connector.
The default position of jumper RTS_E: open.
6.4.3 CTS_E
Closing this jumper enables the CTS line on the RS232_2 connector via the WAKE-UP button.
The default position of jumper CTS_E: open.
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