GPIO Controller

Module Support

The user GPIO interface is supported by only the Fortiq-42 modules.

Speed Modules

Speed Module Support for GPIO Interface

Module	User GPIO Support
Vertiq 81-08	❌
Vertiq 40-06	❌
Vertiq 23-06	❌

Servo Modules

Servo Module Support for GPIO Interface

Module	User GPIO Support
Vertiq 81-08	❌
Vertiq 40-06	❌
Vertiq 23-06	❌
Vertiq Fortiq-42	✅

Description

Vertiq’s GPIO interface provides a flexible method of interacting with a module’s user-specific GPIO pins. Each GPIO can be set to input or output, which can be switched on-the-fly, if desired. Each pin set as an input may choose whether or not to use an internal pull resistor (up or down), as well as the type of pull used. Each pin set as an output may choose whether to output in a Push-Pull or Open-Drain configuration.

All pins set as an input can read the input value, and all pins set to output can read, write, and save the outgoing value. Access to these behaviors is available through registered or addressable methods. Both registered and addressable interactions occur via IQUART commands, and will be covered more below. Vertiq’s GPIO interface has flexibility to change any GPIO parameter via the registered or addressable format. Any savable value set through the IQ Control Center will be stored in the module’s persistent memory, and will be retained through resets and power-cycles. Using Vertiq’s Python API, values can be written, saved, and read.

Registered GPIO Access

The GPIO registers encode each bit to one GPIO (ex. bit 3 corresponds with GPIO3). All registers excluding the Input Values (read only) have Read/Write/Save permissions.

Note

The number of GPIOs available is dependent on the module in use. See your module’s documentation to learn more. Setting values to GPIOs that do not exist on your module will have no effect.

As an example, suppose your motor has 3 user accessible GPIOs. To set all 3 to outputs using Push-Pull configuration and output high on only GPIO 3:

1. Set GPIO Mode to 7

2. Set PP/OD to 0

3. Set Output Values to 4

The GPIO registers are summarized below:

GPIO Registers

Register Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0	Access	Description
GPIO Mode	GPIO 8 Mode	GPIO 7 Mode	GPIO 6 Mode	GPIO 5 Mode	GPIO 4 Mode	GPIO 3 Mode	GPIO 2 Mode	GPIO 1 Mode	R/W/S	Sets the GPIO pin to a specified mode, input or output. 0 indicates input, 1 indicates output
Input Values	GPIO 8 Input	GPIO 7 Input	GPIO 6 Input	GPIO 5 Input	GPIO 4 Input	GPIO 3 Input	GPIO 2 Input	GPIO1 Input	RO	A read only value that indicates the value of each input pin when set to input mode
Output Values	GPIO 8 Ouput	GPIO 7 Ouput	GPIO 6 Ouput	GPIO 5 Ouput	GPIO 4 Ouput	GPIO 3 Ouput	GPIO 2 Ouput	GPIO 1 Ouput	R/W/S	The value to send/being sent on an output GPIO line
Use Pull	GPIO 8 Use Pull	GPIO 7 Use Pull	GPIO 6 Use Pull	GPIO 5 Use Pull	GPIO 4 Use Pull	GPIO 3 Use Pull	GPIO 2 Use Pull	GPIO 1 Use Pull	R/W/S	Determines whether or not to use the internal pull-up or pull-down resistor on input mode. If 0, use no pull, if 1 use the pull type specified by the corresponding Pull Type bit
Pull Type	GPIO 8 Pull Type	GPIO 7 Pull Type	GPIO 6 Pull Type	GPIO 5 Pull Type	GPIO 4 Pull Type	GPIO 3 Pull Type	GPIO 2 Pull Type	GPIO 1 Pull Type	R/W/S	Determines the type to use on an input pin, if Use Pull is set high. 0 indicates pull down, 1 indicates pull up.
PP/OD	GPIO 8 PP/OD	GPIO 7 PP/OD	GPIO 6 PP/OD	GPIO 5 PP/OD	GPIO 4 PP/OD	GPIO 3 PP/OD	GPIO 2 PP/OD	GPIO 1 PP/OD	R/W/S	Determines the output mode, push-pull or open-drain. 0 indicates push-pull, 1 indicates open-drain

Addressable GPIO Access

User GPIOs allow for individual write access to each GPIO. Addressable access is a write only protocol. To set a value via addressable access, send one byte that represents the value to write as well as the GPIO to write to. The MSB represents the value, while the bottom 7 bits represent the GPIO number. For example, to set GPIO 3 to be an output, write 131₁₀ (0b10000011) to the GPIO Addressable - Mode entry (see Initial GPIO Setup and Testing with IQ Control Center)

Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
Value to Set	Target GPIO Number 1 to your modules top-most GPIO Number

Usage

Initial GPIO Setup and Testing with IQ Control Center

The IQ Control Center provides the easiest way to interact with your module’s GPIO peripherals. To do so:

1. Open IQ Control Center. If you have not installed the program, please follow the instructions in Getting Started with Speed Motors Using IQ Control Center.

2. Connect your module to IQ Control Center

3. Select the Tuning Tab on the left side

   

4. Scroll down in the Tuning Tab until you find GPIO Addressable - Mode

   

   This is where you will find access to both registered and addressable GPIO control. In order to read the current GPIO state, you must read from the register values, as addressable access is Write-Only.

5. To test your GPIOs:

   1. Create the following circuit

   

   
   

   2. Write 7 to GPIO Mode Register to set all 3 GPIOs to output

   3. Make sure GPIO Push Pull - Open Drain Register is set to 0, indicating that all outputs are configured as push-pull

   4. Open the Testing Tab in the Control Center, and find GPIO Addressable - Output

      

   5. Write 7 to GPIO Output Register to set all outputs high. You should see your LEDs light up

   6. Write 1 to GPIO Addressable - Output to turn off only GPIO 1

   7. Write 6 to GPIO Mode Register to set GPIO 1 to input and GPIOs 2 and 3 to output

   8. Write 129 to GPIO Addressable - Use-Pull to enable pull on GPIO 1

   9. Write 129 to GPIO Addressable - Pull-Type to set GPIO 1 to pull up

   10. Select the Update Button on GPIO Inputs. You should read 1

   11. Write 6 to GPIO Pull-Type Register to set GPIO1 to pull down. You should now read 0 on GPIO Inputs

Vertiq Python API - GPIO Interface

Note

Please note that the following GPIO Interface testing was performed with a Fortiq-42 module. Your exact commands may change depending on the module in use.

The GPIO interface can also be used through Vertiq’s Python API. To use the API, please use the following steps:

1. If you have never used Vertiq’s Python API, you must first set up your local computer to use the Python API using the instructions found at Getting Started with Python

2. After completing the walkthrough, you can interact with the gpio_controller client

3. To read a value

   print(fortiq.get("gpio_controller", "<entry_name>"))
   

   For example, to read the value stored in the modes_register:

   print(fortiq.get("gpio_controller", "modes_register"))
   

4. To write a value

   fortiq.set("gpio_controller", "<entry_name>", value)
   

   For example, to set the bottom three GPIOs to outputs

   fortiq.set("gpio_controller", "modes_register", 7)
   

5. To save a value to persistent memory

   fortiq.save("gpio_controller", "<entry_name>")
   

   For example, to save the value in the modes_register

   fortiq.save("gpio_controller", "modes_register")