These notes assume that when the board is placed with the header pins facing up, the bottom right of the board is next to the 8 sets of INPUT pin headers.
Inner means between the two rows of header sockets, outer means between the left/right board edges and the header sockets.
SPI2 / External SPI
sclk GPIOB 13
miso GPIOB 14
mosi GPIOB 15
There are 4 pins, labelled CS1-4 next to a label that reads Ext SPI. The 3rd pin is connected to the flash chip on
the bottom right inner of the board. The other pins on the flash chip are wired up to PB3/4/5
SPI3 / SPI
sclk GPIOB 3
miso GPIOB 4
mosi GPIOB 5
ssel 1 GPIOB 10 / Ext SPI CS1
ssel 2 GPIOB 11 / Ext SPI CS2
ssel 3 GPIOB 12 / Ext SPI CS3 - wired up to Slave Select of M25P16 15MBitFlash chip
ssel 4 GPIOB 13 / Ext SPI CS4 - not usable since it is used for SPI2 sclk
There is space for a MS5611 pressure sensor at the top left inner of the board.
There is an I2C socket on the left outer of the board which connects to a PCA9306 I2C level shifter directly opposite (inner).
The PCA9306 is not populated on some boards and thus the I2C socket is unusable.
There is a CAN socket on the top right outer of the board which connects to a MAX3015 CAN Tranceiver.
The MAX3015 is not populated on some boards and thus the CAN socket is unusable.
There are some solder pads labelled Ext 1-4 at the top right inner of the board.
GPIOE 6 / PE6 / Ext 1
GPIOD 3 / PD3 / Ext 2
GPIOD 4 / PD4 / Ext 3
GPIOB 3 / PB3 / Ext 4
There are some solder pads labelled ADC0-3 & Diff Press at the top left inner of the board
They are connected to the ADC socket at the top left outer of the board