Pioneer 2 - Manual (Page 21)

Pioneer Mobile Robots
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Under P2OS control when not connected with a client, pressing and releasing the MOTORS button puts
Pioneer 2 into joystick-drive mode. A subsequent press/release puts it into self-test mode that exercises the
robot's drive, controller, and I/O systems. (See Chapter 5, Joystick andSelf-Test Modes, for details.)
Pressing and holding the MOTORS button in combination with pressing and releasing the RESET button
puts the microcontroller board into a special download mode for reprogramming the onboard flash PROM
and RAM. See Pioneering 2 Operating System and Updating & Reconfiguring P2OS, Chapters 6 and 7.
SERIAL
Pioneer 2's microcontroller has two serial ports and three connectors. One connector, a standard 9-pin D-
SUB receptacle, is located on the Console and is for direct RS232-compatible serial data communication
between the microcontroller and an client computer. SERIAL shares its three-line transmit, receive, and
ground connections with one of the two serial ports that are inside the robot. (See Appendix A for pinouts
and cabling connections.)
Two amber LEDs on either side of the Serial Port flash during actual data activity transmitted from or
received by the microcontroller.
Remove any tether or laptop connection from the Console SERIAL port
when using the optional radio modems.
RADIO
The RADIO slide switch on Pioneer 2's Console controls power to the optional radio modem or Ethernet
radio. The RADIO switch does not affect the SERIAL port functions directly, but you must switch a radio
modem’s power off if you use the Console Serial Port to connect a piggyback laptop or another external
computer to the robot. (The radio modem gets connected to the microcontroller via the internal, shared
serial port.)
FLASH
A slide switch labeled FLASH is recessed into the Console. It write-protects the flash PROM-stored P2OS
software and your Pioneer 2's operating parameters (see Updating and Reconfiguring P2OS, Chapter 7).
When switched forward, toward the front of the robot, FLASH is enabled for writing. (The P2OS utilities
that accompany your robot will warn you if FLASH is disabled.)
Safety Watchdogs and Configuration
Pioneer’s standard onboard software, P2OS, contains a communications watchdog that will halt motion
if communications between a client computer and the server are disrupted for a set time interval, nominally
two seconds (
watchdog ). The robot will automatically resume activity, including motion, as soon as
communications are restored.
Also, Pioneer’s server software contains a stall monitor. If the drive exerts a PWM pulse that equals or
exceeds a configurable level and the wheels fail to turn (
stallval ), motor power is cut off for a
configurable amount of time ( stallwait ). The server software also notifies the client which side is
stalled. When the time elapses, motor power automatically switches back on and motion continues under
server control.
Both these “failsafe” mechanisms help ensure that the robot will not damage objects or be electrically
damaged during operation. You may reconfigure the communications, drive current, and stall-wait values
to suit your Pioneer’s application. (See Chapter 7, Updating & Reconfiguring P2OS, for details.)