FatcatLab EVB¶
The FatcatLab EVB is a LEGO MINDSTORMS EV3 compatible cape for BeagleBone.
Input / Output Ports¶
The EVB uses the LEGO MINDSTORMS EV3 input and output port drives, so please refer to Input / Output Ports in the EV3 section.
Input Port I2C Adapters¶
The ev3dev PRU firmware for FatcatLab EVB creates one I2C
adapter for each input port. These are available at /dev/i2c-X where
X is the number of the input port plus 2. The adapters can only be used
when the port is set to nxt-i2c or other-i2c mode.
Buttons / Joystick¶
The EVB has a directional joystick and a single button for user input. These are mapped to keyboard keys so that they provided the same input signals as the EV3.
Note
Simultaneous button presses are ignored.
| Button/Direction | Linux key code (value) |
|---|---|
| Back button press | KEY_BACKSPACE (14) |
| Joystick button press | KEY_ENTER (28) |
| Joystick up | KEY_UP (103) |
| Joystick left | KEY_LEFT (105) |
| Joystick right | KEY_RIGHT (106) |
| Joystick down | KEY_DOWN (108) |
Battery¶
- This driver is used to get information about the FatcatLab EVB battery.
- It uses the power_supply subsytem.
- It registers a sysfs device node at
/sys/class/power_supply/evb-battery/.
scope |
Always returns System. |
voltage_now |
Returns the battery voltage in microvolts. |
Sound¶
The snd-evb module provedes an ALSA driver for PCM playback and a
Linux input device with sound capabilities (EV_SND) for producing tones.
The ALSA driver can be used with standard tools such as alsamixer and
aplay. Tones can be produced by using the beep command, ioctls such
as KDMKTONE (must run on local console or as root for ioctls) or by
writing SND_* events to the event device (must be member of input
group for this).