RS-485 JUMPERS POSITION
Buzzer
Strato Pi Base has an on-board buzzer that can be controlled using GPIO20. Simply set
GPIO20 to high to emit a continuous sound, and back to low to stop. The buzzer is not
intended to emit sound indefinitely and could be damaged doing so.
The Strato Pi utility has several commands to control the buzzer.
Buzzer on continuously:
$
sudo strato beep on
Buzzer off:
$
sudo strato beep off
Buzzer on for 500 milliseconds:
$
sudo strato beep 500
Buzzer on for 500 milliseconds, followed by 100 milliseconds pause, repeated three times:
$
sudo strato beep 500 100 3
Hardware watchdog
Strato Pi Base implements a dedicated hardware watchdog circuit that can be used to
perform a full power cycle of the Raspberry Pi.
Being controlled by Raspberry Pi’s GPIO pins, it is extremely easy to control watchdog
operation using simple custom scripts in your application.
The watchdog default behavior is described below, but all timing parameters and control
logic can be modified as described in the "Strato Pi Logic Controller Advanced
Configuration Guide" document.
The watchdog is normally disabled. To enable it, set GPIO6 pin to high. While GPIO6 is
high, the Strato Pi controller will watch for state changes of the GPIO5 heartbeat pin. You
should ensure that GPIO5 flips its state between high and low faster than every 60
seconds.
If the Strato Pi Base controller doesn’t see GPIO5 changing state for more than 60
seconds, it will initiate a shutdown procedure, rising the GPIO12 timeout pin to high, to
signal that a watchdog timeout has occurred.
If possible, you should immediately initiate a software shutdown on Raspberry Pi, and set
the GPIO16 shutdown pin to high. When GPIO16 is set to high or 60 seconds after the
timeout, Strato Pi will wait 60 seconds more, then power cycle the Raspberry Pi.
Note that Strato Pi Base will power cycle the Raspberry Pi even if GPIO16 is not set high.
In this case the power cycles occurs 120 seconds after the heartbeat timeout.
The Strato Pi utility can be used to control the watchdog from your own application.
22
Strato Pi Base User Guide
