Command Syntax - Sferalabs Strato Pi Base Advanced Configuration Manual

This serial protocol is implemented over two of the Pi's GPIO pins, one used as the TX line
and the other as RX. The GPIO pins are specific for each Strato Pi version.
Base
UPS
CAN
CM
CM Duo
Communication speed is fixed at 1200 8N1.
The PIC always starts with both AN10/RB4 and AN11/RB5 configured as inputs. When the
PIC senses a valid command and has to reply, it will switch AN10/RB4 to output and keep
it as output indefinitely.
The different versions of Strato Pi also use different GPIO pins for the various control lines.
The following table highlights the features that are controlled by different GPIO pins on
different versions:
Base
UPS
CAN
CM
CM Duo
MCU

Command syntax

Commands are always initiated by the Pi. PIC will only reply when a valid command is
received.
All commands start with the "X" ASCII character, followed by the command identifier and
arguments. No command termination character is required. The PIC replies after the last
character forming a valid command and argument is received. It does not reply to an
invalid command.
CR/LF characters are always ignored.
4
Pi TX Pi RX
GPIO13 GPIO19
GPIO13 GPIO19
GPIO13 GPIO19
GPIO23 GPIO24
GPIO37 GPIO33
Shutdown Watchdog
Enable Enable
GPIO16 GPIO6
GPIO16 GPIO6
GPIO16 GPIO6
GPIO18 GPIO22
GPIO18 GPIO39
RC3 RB7
MCU TX MCU RX
RB4 RB5
RB4 RB5
RB4 RB5
RB4 RB5
RB4 RB5
Watchdog Watchdog
Heartbeat Timeout
GPIO5 GPIO12
GPIO5 GPIO12
GPIO5 GPIO12
GPIO27 GPIO17
GPIO32 GPIO17
RC4
Strato Pi Logic Controller
RB6