Yes, MPU-9250 is on the wish list and i have made the board with this sensor in mind, but want have a prototype with the i2c part, that is
available now. I want evaluate the performance of the desing and it´s impact to GPS, XBEE, ADC and to the IMU itself.
LIA is actually designed as 2 layer, it should be easy to convert it to 4 layer if necessary.
Xbee socket was initially not on the design list, it was a idea during routing. It fits nicely, and only destroy the really nice screen printing on
the real Lea. I prefer having the Xbee Socket instead of the screen printing. Eventually onle 4 pins for mechanical stability and 4 pins electrical remain,
as for now, the full xbee footprint is planned.
Powering section:
Mosfet on/off switch, possibility to attach failsafe battery, support for 6.6V LiFePO4 servos.
Manufacturability:
soldering SD cards on PCB is possible, placing it with P&P too and there are some usb flash card around that are made in this manner.
It must be glued on the pcb, like the GPS module and this side must be assembled first.
The downside is, if the Flash dies, it cannot be replaced or fitted afterwards.
RS485:
depending on the remaining size, either additional or as replacement to can, can bus will remain.
RS485 for two reasons, digital servos that gives back torque and that work on 2S lipos without needing BEC.
It´s a nice to heave feature, but having only 3x RS232, 1 for GPS, 1 for Modem, 1 for MBUS, there is no space for other,
so ATTiny85 is needed in order to act as bridge for i2c and M-BUS (Multiplex Sensor Bus), the next nice to have feature.
No, seriosly, the 2 layer are test projects. So the other reason is, if 2 layer and GPS/RF/... don´t work reliable compared to the 4Layer version,
then i want using the board otherwise, as RS485 Logger or DMX controller, Can to Modbus Gateway,
IF it don´t work as
USB:
On LIA/LISA, actually all connectors are on top. With the gps addition, only the gps module, sd-card, leds, some servo transistor/mosfets
and resistors/... are on top, the connectors need to be mounted on bottom. This implies that i don´t have space for the usb connector, at
least now. The USB cable should be possible to seldered on the PCB.
Further i want use a min jack, these intendet for video, 4 pol as usb/rs232 communication port. This is the reason why i consider adding
either PESD5V/12V or PRTR5V , depending of the available space and overall price. This as footprint, it don´t tell it must be assembled.
> MPU-9150 footprint inside ASPIRIN footprint.