Overview

IOT-GATE-RPI4 runs standard Raspberry Pi OS with an additional IOT-GATE-RPI4 OS Configuration Layer that sets-up the gateway peripheral devices and provides useful tools for device configuration and management.

Connection and Login

Use the following username and password to login into the Raspberry Pi system via serial console or ssh.

raspberrypi login: pi
Password: raspberry

Cellular Modem

IOT-GATE-RPI4 cellular interface is implemented with a mini-PCIe cellular modem module and a nano-SIM socket. To set up IOT-GATE-RPI4 for cellular functionality, install an active SIM card into the front panel nano-SIM socket U20. The cellular module should be installed into mini-PCIe socket P9.

ModemManager

The ModemManager can be used to log into almost any Internet Service Provider with simple configuration setup.

In the following example:

Replace ISP-APN with the APN name of the cellular provider.

pi@raspberrypi:~$ sudo nmcli connection add type gsm ifname '*' con-name CellularCon apn ISP-APN

Connect cellular network

pi@raspberrypi:~$ sudo nmcli connection up CellularCon

Disconnect cellular network

pi@raspberrypi:~$ sudo nmcli connection down CellularCon

WiFi

Please refer to the Raspberry Pi OS documentation for detailed instruction about configuring WiFi and connecting to Access Point.

Please note, IOT-GATE-RPI4 is pre-configured in the config.txt to use the IOT-GATE-RPI4 external antenna with the WiFi module.

dtparam=ant2

Industrial Interfaces

IOT-GATE-RPI4 implements industrial interfaces with four I/O slots (IE) that can be fitted with up-to four different I/O modules. Slots are referred to as A, B, C and D.

Available I/O modules types:

CAN bus
RS232 (2-wire)
RS485 (half duplex)
Digital I/O (4x DI + 4x DO)

CAN

CAN function is implemented with MCP2518FD controller interfaced with Raspberry Pi CM4 SPI ports. CAN modules can be installed in any I/O slot: A, B, C and D. Up to four CAN modules can be installed simultaneously.

Enable/Disable CAN module

To enable/disable CAN module on a specific industrial I/O slot please use iotg-rpi4-config utility.

Configuration and Access

Once properly enabled on a specific I/O slot, CAN interface can be accessed in Linux via canX network interface, where X is a slot name: A, B, C, D

The following example demonstrates how to configure and use CAN module installed into industrial I/O slot B.

CAN interface configuration

Configure the CAN interface bit-rate to 1 Mbits/sec:

pi@raspberrypi:~$ sudo ip link set canB type can bitrate 1000000

Enable the CAN interface:

pi@raspberrypi:~$ sudo ip link set canB up

Software installation

Use the following command to install can-utils if not installed:

pi@raspberrypi:~$ sudo apt-get install --no-install-recommends can-utils

Send/Receive packets

Use cansend and candump utilities to send and receive packets via CAN interface.

Send standard CAN frame (on the first device):

pi@raspberrypi:~$ sudo cansend canB 111#1122334455667788

Send extended CAN frame (on the first device):

pi@raspberrypi:~$ sudo cansend canB 11111111#1122334455667788

CAN frames (extended mode) generator, random payload, interval between two successive flames 50 msec:

pi@raspberrypi:~$ sudo cangen -g 50 -e -D r -v canB
...
  canB  1E5137F4#0F.4D.8B.7A.25.4D.DB.21
  canB  1B6C965C#8C.DE.96.58.69.5F.D5.26
  canB  1BD23086#8D.DB.C4.3E.81.57.BA.34
  canB  127B2322#F4.16.31.2E.34.04.62
  canB  1A6366DB#A8.73.C0.37.D8
  canB  03620EE4#
  canB  023AC34D#C6.08.BD.2A.04.B3.BF.43
  canB  1C19AD2E#09.C1.B3.26.23.E5.6A.5A
  canB  02BCA994#48.32.46.7C.F0.3F.29.1E
  canB  08104C67#59.9F.FE.44
  canB  1C280582#6F.D4.9C.38.A5.28.A3
  canB  0BC219EE#D9.2C.05
  canB  04AA80B8#A1.93
  canB  1A3E2392#AD.98
  canB  0025950E#E3.99.38
...

Dump all received data frames as well as error frames (on the second device):

pi@raspberrypi:~ $ sudo candump any,0:0,#FFFFFFFF
...
  canB  0CC89C1A   [1]  51
  canB  0A097EFB   [0] 
  canB  02B59BD5   [5]  68 6F 47 64 D9
  canB  03743A1E   [7]  FA BF E4 38 3E BF C8
  canB  13C9B644   [8]  30 FB 60 6F E1 FC 55 65
  canB  018A8975   [0] 
  canB  0C9C8179   [0] 
  canB  011F5D90   [6]  65 DB DD 5A AA F9
  canB  07B7FD18   [6]  CC 96 26 1D 13 7C
  canB  1FBD7177   [8]  69 BF 8D 1E 4C 0D 73 02
  canB  107A7E2D   [2]  25 D3
  canB  12B9E279   [8]  89 77 B7 54 BD 98 83 06
  canB  112A44EA   [8]  9E 95 D9 6B 60 CE B4 52
  canB  0ADF9869   [3]  C8 A0 27
  canB  1580C274   [5]  B2 7A F7 43 04
  canB  06DDDBCC   [7]  AF 19 88 04 E4 D8 95
  canB  127FA5CE   [8]  F7 54 57 20 45 17 3D 12
  canB  09A37893   [0] 
  canB  01BA4332   [6]  0B AF 0C 2E AB 25
  canB  180A8AD5   [5]  68 BE F7 5A C0
  canB  06DC994E   [7]  20 9E E9 7B B8 31 BC
...

RS232

RS232 function is implemented with MAX3221 (or compatible) transceiver interfaced with Raspberry Pi CM4 UART ports.

RS232 modules can be installed in any I/O slot: A, B, C and D. Up to four RS232 modules can be installed simultaneously.

Enable/Disable RS232 module

To enable/disable RS232 module on a specific industrial I/O slot please use iotg-rpi4-config utility.

Configuration and Access

Once properly enabled on a specific I/O slot, RS232 interface can be accessed in Linux via ttyRS232_X tty device, where X is a slot name: A, B, C, D.

RS485

RS485 function is implemented with MAX13488 (or compatible) transceiver interfaced with Raspberry Pi CM4 UART ports.

RS485 modules can be installed in any I/O slot: A, B, C and D. Up to four RS485 modules can be installed simultaneously.

Enable/Disable RS485 module

To enable/disable RS485 module on a specific industrial I/O slot please use iotg-rpi4-config utility.

Configuration and Access

Once properly enabled on a specific I/O slot, RS232 interface can be accessed in Linux via ttyRS485_X tty device, where X is a slot name: A, B, C, D.

Modbus RS485

The following example demonstrates how to use RS485 module installed into industrial I/O slot A in a Modbus RS485 Network. IOTG-RPI4 performs as a Master device and queries XY-MD02 temperature and humidity sensor.

Software installation

Download and install modpoll - a command line based Modbus master simulator and test utility.

pi@raspberrypi:~$ wget https://www.modbusdriver.com/downloads/modpoll.tgz -P /tmp/
...
pi@raspberrypi:~$ sudo tar -xvf /tmp/modpoll.tgz -C /opt/
...

Device connection

--------------------                                  -------------------------
|                  |                                  |                       |
|                  *--(+)---< <------------- 5V-30V   |        IOTG-RPI4      |
|                  |                                  |                       |
|                  *--(-)---< <-------------- GND     |------  ------------   |
| XY-MD02 (RS485)  |                                  |     |==| IE-RS485 |   |
|                  *--(A+)--< <---...---> >---(2)---*-|     |  ------------   |
|                  |                                  | P17 |     Slot A      |
|                  *--(B-)--< <---...---> >---(4)---*-|     |                 |
|                  |                                  |------                 |
--------------------                                  -------------------------

Read data

Read temperature once:

pi@raspberrypi:~$ /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 1 -r 2 -1 /dev/ttyRS485_A 
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 2, count = 1
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave...
[2]: 255

Poll temperature:

pi@raspberrypi:~$ /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 1 -r 2 /dev/ttyRS485_A 
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 2, count = 1
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave... (Ctrl-C to stop)
[2]: 256
-- Polling slave... (Ctrl-C to stop)
[2]: 255
-- Polling slave... (Ctrl-C to stop)
[2]: 256
...

Read humidity once:

pi@raspberrypi:~$ /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 1 -r 3 -1 /dev/ttyRS485_A 
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 3, count = 1
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave...
[3]: 684

Poll humidity:

pi@raspberrypi:~$ /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 1 -r 3 /dev/ttyRS485_A 
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 3, count = 1
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave... (Ctrl-C to stop)
[3]: 568
-- Polling slave... (Ctrl-C to stop)
[3]: 566
-- Polling slave... (Ctrl-C to stop)
[3]: 563
...

Read temperature & humidity once:

pi@raspberrypi:~$ /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 2 -r 2 -1 /dev/ttyRS485_A                             
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 2, count = 2
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave...
[2]: 258
[3]: 408

Poll temperature & humidity:

pi@raspberrypi:~$ /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 2 -r 2 /dev/ttyRS485_A 
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 2, count = 2
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave... (Ctrl-C to stop)
[2]: 258
[3]: 406
-- Polling slave... (Ctrl-C to stop)
[2]: 258
[3]: 406
-- Polling slave... (Ctrl-C to stop)
[2]: 258
[3]: 405
...

Read slave address, baudrate, temperature & humidity corrections:

pi@raspberrypi:~$ /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 4 -c 4 -r 258 -1 /dev/ttyRS485_A                          
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC3
Slave configuration...: address = 1, start reference = 258, count = 4
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, output (holding) register table

-- Polling slave...
[258]: 1
[259]: 9600
[260]: 0
[261]: 0

RTC

IOT-GATE-RPI4 RTC is implemented with the AM1805 real-time clock (RTC) chip.
By default RTC is installed and pre-configured in the IOT-GATE-RPI4 OS Configuration Layer provided by CompuLab.

Accessing and setting the RTC

To access the RTC time and date run:

pi@raspberrypi:~$ sudo hwclock
2021-12-17 18:49:47.763197+02:00

To set the date and write it into the RTC do the following:

pi@raspberrypi:~$ sudo date -s "31 Dec 2021 10:00:00"                                                                                     
Fri Dec 31 10:00:00 IST 2021
pi@raspberrypi:~$ sudo hwclock -w
pi@raspberrypi:~$ sudo hwclock 
2021-12-31 10:00:08.317403+02:00

Enable/Disable RTC via device tree overlay

To enable/disable IOT-GATE-RPI4 RTC add/remove(comment) the following string in the config.txt file:

dtoverlay=iotg-rpi4/iotg-rpi4-rtc

Watchdog

IOT-GATE-RPI4 watchdog function is implemented with the AM1805 RTC chip.
By default watchdog is installed and pre-configured in the IOT-GATE-RPI4 OS Configuration Layer provided by CompuLab.

pi@raspberrypi:~$ sudo systemctl show | grep -i watchdog
RuntimeWatchdogUSec=10s
ShutdownWatchdogUSec=2min
ServiceWatchdogs=yes

Watchdog configuration

Edit /etc/systemd/system.conf file to configure watchdog related parameters, in particular RuntimeWatchdogSec and ShutdownWatchdogSec.

Watchdog testing

Run the following command to simulate kernel panic:

pi@raspberrypi:~$ sudo su
root@raspberrypi:/home/pi# echo "c" > /proc/sysrq-trigger

As a result, the watchdog is not fed and the system reboots after 10 sec.

Trusted Platform Module

IOT-GATE-RPI4 features an optional on-board TPM implemented with Infineon SLB9670XQ2.0 interfaced with CM4 SPI port.

TPM is mutually exclusive with I/O slot D

Enable/Disable TPM module

To enable/disable TPM module please use iotg-rpi4-config utility.

LEDs

IOT-GATE-RPI4 features two user Bi-Color (Red + Green) LEDs controlled via GPIO pins.

User LED1

Set Red ON

pi@raspberrypi:~$ gpioset 3 12=0

Set Red OFF

pi@raspberrypi:~$ gpioset 3 12=1

Set Green ON

pi@raspberrypi:~$ gpioset 3 13=0

Set Green OFF

pi@raspberrypi:~$ gpioset 3 13=1

User LED2

Set Red ON

pi@raspberrypi:~$ gpioset 3 14=0

Set Red OFF

pi@raspberrypi:~$ gpioset 3 14=1

Set Green ON

pi@raspberrypi:~$ gpioset 3 15=0

Set Green OFF

pi@raspberrypi:~$ gpioset 3 15=1

IOT-GATE-RPI4: Raspberry Pi OS: How-To Guide

Contents

Overview

Connection and Login

Cellular Modem

ModemManager

WiFi

Industrial Interfaces

CAN

Enable/Disable CAN module

Configuration and Access

CAN interface configuration

Software installation

Send/Receive packets

RS232

Enable/Disable RS232 module

Configuration and Access

RS485

Enable/Disable RS485 module

Configuration and Access

Modbus RS485

Software installation

Device connection

Read data

RTC

Accessing and setting the RTC

Enable/Disable RTC via device tree overlay

Watchdog

Watchdog configuration

Watchdog testing

Trusted Platform Module

Enable/Disable TPM module

LEDs

Navigation menu

Search