Overo

=Gumstix Overo=
The Overo is a module sold by Gumstix which contains a TI OMAP35xx processor (ARM Cortex-A8). This module is used on the Lisa board or, through the use of standard gumstix baseboards such as Tobi, it can be interfaced to LPC2148 boards such as the twog.
== Using Paparazzi pre-built toolchain ==
Compiling overo programs is easy in paparazzi. Install the paparazzi-omap ubuntu package, create an SD card (sw/tools/overo_sd_maker) with a the required boot files (MLO, uboot, uImage) and rootfs, and you're ready!
Examples on how to perform telemetry, datalink, and other basics are provided in the sw/airborne/fms and sw/airborne/beth directories. Lisa board owners can also look there for info on interfacing to IMU/SPI/baro/etc.
Since overo is on the network (onboard or usb wifi), uploading overo programs is done using scp (See conf/Makefile.omap). Network configuration script is available at sw/tools/overo_sd_maker/configure_network.sh
== Setting up a build environment ==
This is not necessary unless you want to build your own custom kernels or root filesystems. 
Instructions given here
can be used to generate a generic omap image (omap3-console-image for example). 
For paparazzi there is a custom image recommended (realtime kernel patch and other extras) and specific instructions are listed on the Lisa pages.
= Communications between LPC and Overo via UART =
An example implementation of an overo communicating with a twog is structured as follows:
The overo target application is sw/airborne/beth/overo_test_uart.c
The twog configuration is conf/airframes/twinjet_overo.xml
==Highlights:==
: The Twog's GPS UART is repurposed to establish communications between Overo and Twog
: Twog uses a software module (sw/airborne/modules/core) to permit having an extra telemetry channel on the free UART
: The GPS is interfaced to the overo and the overo forwards the ublox messages to the twog
: Overo sends datalink messages to the Twog who accepts them just like they were from the ground station
: Overo receives twog messages and parses them
: Overo can exchange telemetry and datalink with ground station as usual (over ethernet/wifi UDP)
: Twog can exchange telemetry and datalink with ground station as usual (over serial Xbee)
==Hardware configuration:==
The hardware is connected according to this logical block diagram:
 TWOG OVERO
+------------+ +-----------+ +-----+
| Uart0+-------+Uart Uart+-----+ GPS |
| Uart1| | wifi| +-----+
+----------+-+ +---------+-+
 \ / 
 \ / 
 \ / 
 +-+-------------+-+
 | Ground Station |
 +-----------------+
The overo serial connections can be accomplished via the OMAP processor UARTS (1.8v level-shifting required) or via USB to serial converters (for testing this is easy to setup and convenient for debugging but too bulky to fly).
A U-Blox LEA-5H GPS is needed (an LEA-4H could be used with few sw modifications). A booz GPS board is ideal, but in this example we use a Tiny board with the uart tunnel application installed (GPS characters are tunneled through the processor).
Here are pictures of the example setup:
==Software configuration:==
===Setting up Overo: ===
Create aircraft : 
Either using paparazzi center or by manually editing conf/conf.xml, use the 
example conf/airframes/Poine/beth.xml to create a new aircraft
exerpt of conf.xml:
exerpt of conf.xml
edit makefile to add correct overo hostname
edit beth/overo_gcs_com.c to add correct ground station IP address
====Compiling application====
 make AIRCRAFT=BETH clean_ac overo_test_uart.compile
 make AIRCRAFT=BETH overo_test_uart.upload
====Running application====
 ssh overo
 ./overo_test_uart.elf 0 1
===Setting up Twog:===
Create aircraft using twinjet_overo.xml
build/upload via paparazzi center
Category:Hardware Category:Software Category:Developer_Documentation