cuspaceflight/avionics14

CUSF Avionics 2014

Firmware Compilation

Designed to be compiled with the GNU ARM Toolchain - https://launchpad.net/gcc-arm-embedded

The project should simply compile with

make

avionics14's Issues

Radio Schematics

• Remove receiver radio
• Rename hierarchial pins to e.g. RADIO_MISO, RADIO_CS, RADIO_CLK
• Antenna_Out doesn't appear to be connected
• Antenna should be connected to an antenna connector symbol (see M2R schematic for example)
• No need for junctions on every pin
• Pullup resistors should be given values (use the 'v' key, and say 10k)
• Should put a 100nF and 1uF capacitor across power pins

IMU Schematics

No schematics actually exist yet.

• Copy from M2FC's IMU sheet
• Omit the high-G accelerometer

Race condition fix probably worse than cure

https://github.com/cuspaceflight/avionics14/blob/master/firmware/adxl3x5.c#L282-L286

Looks like we lock before sleeping and hold the lock until we wake up from timeout. Should be enough to just have the interrupt check the thread it has a handle on is not already awake.

Status indication

If the mission control team could add a couple of bits to the schematic that would be great. We'll definitely need these but I forgot to mention them when we originally wrote down all the parts of the schematic.

• Some status LEDs (connected to GPIOs on the microcontroller) to indicate whether there's an error or things are OK. In the past I've had e.g. one for "Pyros", one for "Radio", one for "IMU" so that LED can blink if there's an error. We might want to try just having a green "OK" or red "ERROR" LED instead to save parts.
• A beeper would be a really nice extra. I'm not sure on the best choice here but I'm sure Farnell carries some small beepers (might also be called piezo sounders). Something small and perhaps a single n-channel MOSFET to drive it from the battery voltage would work.

GPS Schematics

• Double check ON/OFF should be connected directly to WAKEUP, perhaps we can just tie WAKEUP on and switch ON/OFF ourselves
• ON/OFF line is not actually connected to that label (needs a junction or draw a horizontal line from the label to intersect the existing wire)
• Check I2C resistors are as-per datasheet, as typically pullups and not series resistors are used (but this might be OK)
• Should TM_GPIO5 be connected to something? It just has a bit of wire at the moment
• Add no-connects (press q or use the X button on the right) to non-connected pins
• Rename labels to reflect the pin's name. Since the name is mostly for the purpose of connecting on the microcontroller, it is more helpful if it's named "GPS_SDA" rather than "Connect to microcontroller I2C SDA"
• I2C labels should be SDA and SCL for conformity with I2C standard
• Only need one of I2C, SPI or Serial to interface to the microcontroller, and probably serial is easiest
• Antenna needs adding, see M2R schematic for example
• Add 100nF capacitor to power pins

Pyro Schematics

• P channel MOSFETs are upside down
• Transient suppreson diode could be down-specced to a small ESD diode to save cost and space
• Add connectors instead of the hierarchial labels for the actual pyro connections, see KiCAD library part CONN_2
• Add continuity checking

SD Card Schematics

• I think 47k pullups is the standard value
• Swap to SDIO instead of SPI connections
• No need for transient suppressor here
• Change to 100nF capacitor

Radio schematic

Not sure about the following connections, please advise+ point out anything else

1. Judging by this connection to an Arduino board: http://jeelabs.org/2009/02/10/rfm12b-library-for-arduino/ (used for sending packets between modules)
   It seems that only the SPI pins: SDO, SDI, nSEL and SCK are needed for communication with a microcontroller. so I've left pin 3-5 unconnected for both transmitter and ground station.

2. The interrupt, reset and interrupt request pins are active low, so I've used 4k7 resistors to pull them up to vcc.