1. Switch to
STM32F405RGT6. This requires removing JP12 and JP13 which are labeled on the silkscreen as CMP1 and CMP2
2. Changing certain I/O. We are going to use the I2C1 SDA and SCL pins (connected to PB6 and PB7 on the MCU) as UART1 RX and TX so we can fully use the F4's DMA on that Serial channel. This means that the current UART1_RX (coming from PA10 on the MCU) is being re-purposed as a PPM output using TIM1CH3. What needs to be populated on the board for this to work are the two jumpers where the I2C1 level-shifter IC is located, and a 10k Resistor on the RX (SDA) line. These are marked in the schematic as JP10, JP11, and R34.
3. Populating the JTAG connector with an FTSH-105-04-F-DV-K or similar connector (based on what you have in stock)
4. Switching the Servo Header Pins to single straight pins from the signal line pointing under the board
UPDATE November 2012: Lia now includes CAN bus support!
Based on theLisa/M v2.0 and with a footprint of just 34mm by 58mm, Lia is our most economical autopilot. However, it is built around the same 72MHz 64-pin STM32 processor as Lisa/M and can control fully autonomous fixed-wing, multicopter, or even transitioning vehicles (like theQuadshot) with ease. Also, its low cost and CAN interface mean it can also be used as networked extension for Lisa/M (or other devices) when many servo-style outputs are needed. Bring on the 16-rotor multicopters!
The biggest difference between Lia and Lisa/M is that Lia uses 0.1" through-holes rather than Molex Picoblade connectors to make connecting peripherals simpler and less costly - just solder up header pins or wire directly into the board!
The other main differences from Lisa/M:
- I2C level shifter removed
- 5V voltage regulator removed
- JTAG connector removed
- Added provisions for multiple BEC input balancing on servo connectors
Lia includes eight 3-pin PWM outputs for connecting servos and ESCs, CAN bus support, three UART serial interfaces (for GPS, xBee, etc), and connections for up to two 2.4GHz Spektrum® DSM2-compatible remote-control satellite receivers. It can mount an Aspirin IMU onboard without increasing the overall footprint, and is compatible with the Paparazzi UAV project software.
The Aspirin series represents the next generation of ultra-small, flat Inertial Measurement Units (IMUs). Aspirin works seamlessly with Lia for easy attitude estimation in the smallest package possible. Using estimators built into the Paparazzi software, update rates of up to 512 times per second are possible.
Two levels of Aspirin are available pre-mounted onto Lia:
- A full 10 degree-of-measurement (DoM) unit that combines the InvenSense MPU-6000 3 - axis accelerometer and 3 - axis gyroscope chip, the Honeywell HMC5883 3 - axis magnetometer, and the Measurement Specialties MS5611-01BA03 barometer. Perfect for getting started in UAVs while allowing graduation to fully autonomous flight.
- A 6 DoM unit with only the InvenSense MPU-6000 populated. The lower-cost option for those most interested in RC flight of multicopters and/or transitioning vehicles like the Quadshot.
Lia is programmed via a bootloader, which allows quick programming over the micro-USB connector.
Lisa (and Lia) documentation on the Paparazzi wiki
Aspirin documentation on the Paparazzi wiki
IMU configuration files can be found at the following links:
Aspirin v1.5 - sample config file only, IMU should be calibrated after mounting on the vehicle.
Aspirin v2.1 - although the unit comes factory calibrated, we recommend that users calibrate the unit after mounting on the airframe for optimal performance.
The software and documentation are a community effort, and as such are continually being improved. Have fun and see you on the Paparazzi email list, the Paparazzi wiki, the Quadshot wiki, and the #paparazzi freenode IRC channel!