board-descriptions.txt

rs485
connect gnd and vcc
R0 connects to the TX of rpi
DI connects to RX of rpi
re & de are enables - send to gip of rpi (nothing special about pin on rip)
*TERMINATING RESISTOR* - probably with ZY
A&B and Z&Y are pinned out in the connector

imu (BNO55)
SDA&SCL - must be equal length connect to SDA and SCL in the rpi, AND to the shield connector
PS1 & PS0 are mode select pins, pull low for i2c
PS0 pull low (ground)
PS1 pull low (ground)
ADR pull low (ground)
*LOOK AT NAVIGATION BOARD FROM LAST YEAR FOR EXAMPLE OF USAGE*

Pressure sensor
i2c address 0x76

i2c differential line chip (PCA9615)
Pin out all to board to board connector
*check data sheet for VDDA and VDDB*
SCL&SDA
*check data sheet for EN*
pin out all P/M differential lines
*make sure all of the traces are as short as possible*

MISC
water ingress detector
well placed test points
two additional header pins for i2c (one for scl and one for sca)
pin out 5v 3.3v and gnd
pin out rx and tx from rpi
pin out all four lines of rs485 differential chip
pin out two pwm lines for leds and servo, originate on rpi