Expansion Board User Guide

Flux Board

8-channel Relay Board with DIP switch for stacking additional Flux boards together on the same bus. Relays are ordered in a counterclockwise fashion starting from GPIO496, which is the first relay on the top left closest to the DIP switch. GPIOs may change their numbering based on the DIP switch setting:

Interfaces

  • GPIOs - Relay gpio controls, active low

DIP GPIO Switch Ranges

  • 000 => 496..503
  • 100 => 480..487
  • 010 => 464..474
  • 001 => 448..455

uEnv.txt entry:

Driver appears as exportable GPIO chips on the board. Check /sys/class/gpio/ for gpiochip496 entry.

Example script for toggling relays:

Horizon Lite (Rev C)

Interfaces

  • /dev/ttyS3 - Cell Module Serial Port
  • /dev/ttyS1 - (J15) RS-422/485 Serial Interface
  • Note includes 120 Ohm termination resistors - R54/55
  • /sys/bus/iio/devices/iio\:device0/ - (J16) External 12-bit 8-channel ADC
  • Check name = ad7091r8 to ensure correct ADC is enumerated
  • Check ~/provisioning.txt for calibrated channel values

uEnv.txt entry:

ADC Communication

Getting ADC values - Basic

  • 8 channels available from 0 to 7

J16 pin order - looking directly at the connector on the side

Example counts->milliamps formula using point-slope formulae

%FS can be directly multiplied by the full scale to get the measured value. For instance, a 0-10,000 PSI sensor would measure 6,790 PSI at the above measurement.

RS-422 Communication

Testing Serial Output - Basic

Basic Cell Communication

AT Commands

  • AT - comms check - responds with OK
  • AT+CREG? - modem registration check
  • 0,1 - registered home
  • 0,2 - searching
  • 0,3 - registration failed, not searching, check CEREG and CGREG if registered on different band
  • 0,5 - registered roaming
  • AT+CEREG? - LTE modem registration check
  • AT+CGREG? - LTE modem registration check
  • AT+COPS? - operator check
  • AT+CSQ - signal quality, see modem AT command datasheet for specific ranges
  • AT+CGDCONT? - show pdp context list
  • the PDP context needs to be set for the SIM card so that network registration can take place
  • AT+CPIN? - check if SIM card is correctly inserted and ready

Related Links

  • EG95 AT Commands
  • Cellular FPLMN Management
  • Hologram Modem Diagnostics
sudo apt-get install minicom

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