The CP-IO22-A4-2 is an IO board accessory for the ComfilePi consisting of 22 digital IO (11 inputs, 11 outputs), 4 16-bit analog inputs, 2 12-bit analog outputs, screw terminals, and indicator LEDs. It can be mounted to the rear panel of the ComfilePi.

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The following is an example project illustrating how to program the CP-IO22-A4-2 in C# using the Mono Framework.

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This example PInvoke's the pigpio library. For more information see the PInvoke documentation and the pigpiod C interface documentation

CP-IO22-A4-2 pins are connected to the ComfilePi's GPIO header as shown below.

• INPUT : GPIO 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 16
• OUTPUT : GPIO 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27
• AD IN/OUT : I2C1 SDA, I2C1 SCL

• Input Voltage: 5VDC (powered by ComfilePi's 5V pin)
• Current Rating: 500mA or more
• Humidity: 35 ~ 85% RH
• Temperature: -30 ~ 60 ℃
• Size: 128mm X 78mm

• IC: ADS1115IDGST
• Interface : I2C
• Address: 0x48
• Input Voltage Range : -5Vdc ~ 0 ~ 5Vdc
• Resolution : 187.5uV / 1bit (-26,666 ~ 0 ~ 26,666)
• Sample Rate : 1.62mS

• IC: MCP4725A1T-E/CH
• Interface : I2C
• Address: Ch1-0x62, Ch2-0x63
• Output Voltage: 0 ~ 5Vdc
• Resolution : 1.22mV / 1bit (0 ~ 4094)
• Sample Rate : 12uS
• Maximum Output Current : 20mA

• Voltage Range: 12 ~ 24V
• Absolute Min/Max Voltage Range: 3.3 ~ 28V
• Response Time: 5ms
• Input OFF Level: <1.8VDC
• Input ON Level: >2.5VDC
• Indicator LED OFF Level: <4.5V
• Indicator LED ON Level: >5.0V

• DC Output Sink (NPN) x 11
• Maximum Output Voltage: 30VDC
• Response Time: 10ms
• Current: 150mA

It may be necessary to modify the ComfilePi's initial GPIO output state to prevent the ComfilePi from turning the outputs ON when the ComfilePi boots.

1. Backup the existing /boot/dt-blog.bin file.

   cp /boot/dt-blob.bin dt-blob-backup.bin

2. Run the following command to decompile the /boot/dt-blog.bin file.

   sudo dtc -I dtb -O dts -o dt-blob.dts /boot/dt-blob.bin

3. Open the resulting dt-blob.dts file in a text editor and navigate to the pins_cm3 { pin_config { … node.
4. Add the following to the pins_cm3 { pin_config { … node:

   pin@p17 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO17
   pin@p18 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO18
   pin@p19 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO19
   pin@p20 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO20
   pin@p21 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO21
   pin@p22 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO22
   pin@p23 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO23
   pin@p24 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO24
   pin@p25 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO25
   pin@p26 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO26
   pin@p27 { function = "output"; termination = "no_pulling"; polarity = "active_low"; startup_state = "active"; }; // GPIO27

5. Recompile the dt-blob.dts file replacing the existing /boot/dt-blob.bin file.

   sudo dtc -I dts -O dtb -o /boot/dt-blob.bin dt-blob.dts

6. Reboot and the outputs should all be OFF when the ComfilePi is booted.