OLIMEX© 2012
STM32-P207 user's manual
2 b RST button
4 status LEDs + PWR LED
6.18 Notes on interfaces
Note that due the evaluation nature of the board not all interfaces are immediately available on the
proto area. Some of the signals are used by peripherals and other devices.
One of those interfaces were the 3 x I2C which were sacrificed for additional peripherals and
signals that are hard to implement on software level.
There are ways, of course. Depends on which interface you are willing to let go. I will list the
options in the following order (I2C number - processor pin - signal - interface affected):
I2C1_SCL - 139 - CAN1_RX - CAN interface
I2C1_SDA - 140 - CAN1_TX - CAN interface
I2C2_SCL - 11 - A0 - the additional memory
I2C2_SDA - 10 - A1 - the additional memory
I2C3_SCL - 100 - MCO1 - camera interface
I2C3_SDA - 99 - SD_D1/DCMI_DB - SD card / camera
To my mind, the best idea would be to disable the CAN interface.
When you have chosen the preferred I2C port you need to decide whether to remove the peripheral
it is connected to or to disable it by software means (instead of removing components just always
set the needed signals as outputs - disable input and connect additional wires). The final thing to do
is to use 2.2k pull-up resistors on the lines you have chosen (for instance I2C1_SCL and
I2C1_SDA) - I2C requires pull-ups.
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