Difference between revisions of "Unit RPIGPIOEXPANDER"

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----
 
----
  
−
''To be documented''
+
'''Raspberry Pi Firmware GPIO Expander Driver unit'''
 +
 
 +
As of February 2017 the Raspberry Pi firmware contains a mailbox interface to allow control of the GPIO expander on the Raspberry Pi 3/4 and Compute Module 3/4.
 +
 
 +
Unlike the earlier virtual GPIO interface this mailbox service now supports most GPIO functionality including getting and setting a pin value, getting and changing the pin function and getting or changing the pull up/down options.
 +
 
 +
This driver implements most of the functionality available in the new mailbox service as a standard Ultibo GPIO device and also provides direct mailbox calls to allow access to any additional options not covered by the GPIO device API.
 +
 +
When included in a project this driver replaces the Virtual GPIO functions provided by the PlatformRPi2, PlatformRPi3, PlatformRPi4 units.
 +
 
 +
According to /arch/arm/boot/dts/bcm2710-rpi-3-b.dts the following pin assignments are known:
 +
 +
* GPIO_PIN_2 = Activity LED
 +
* GPIO_PIN_4 = HDMI Detect (Input / Active Low)
 +
* GPIO_PIN_7 = Power LED (Input / Active Low)
 +
 
 +
For the Raspberry Pi 3B+ the assignments shown in /arch/arm/boot/dts/bcm2710-rpi-3-b.dts have changed as follows:
 +
 
 +
*GPIO_PIN_2 = Power LED (Active Low)
 +
*GPIO_PIN_4 = HDMI Detect (Input / Active Low)
 +
 
 +
For the Raspberry Pi 4B the assignments shown in /arch/arm/boot/dts/bcm2711-rpi-4-b.dts are:
 +
 +
*GPIO_PIN_0 = Bluetooth Power (Active High) (BT_ON)
 +
*GPIO_PIN_1 = WiFi Power Sequencer (Active Low) (WL_ON)
 +
*GPIO_PIN_2 = Power LED (Active Low) (PWR_LED_OFF)
 +
*GPIO_PIN_3 = (GLOBAL_RESET) (ANT1 on CM4)
 +
*GPIO_PIN_4 = SDIO 1.8V regulator (Active High) (VDD_SD_IO_SEL)
 +
*GPIO_PIN_5 = CAM1 regulator (Active High) (CAM_GPIO)
 +
*GPIO_PIN_6 = SD VCC regulator (Active High) (SD_PWR_ON)
 +
*GPIO_PIN_7 = (SD_OC_N) (ANT2 on CM4)
 +
 
 +
The Pi 400 and CM4 files at bcm2711-rpi-400.dts and bcm2711-rpi-cm4.dts show identical assignments as the Pi 4B.
 +
 
 +
Note that this driver requires recent firmware (later than February 2017) and has been tested successfully with the firmware release from 8 October 2020.
 +
 +
The latest version of the firmware is available from https://github.com/raspberrypi/firmware
  
 
=== Constants ===
 
=== Constants ===
 
----
 
----
  
−
''To be documented''
+
 
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 20px; padding-bottom: 15px;">
 +
<div style="font-size: 14px; padding-left: 12px;">'''RPiGPIO expander specific constants''' <code> RPIGPIOEXP_GPIO_* </code></div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
| <code>RPIGPIOEXP_GPIO_DESCRIPTION = 'Raspberry Pi Firmware GPIO Expander';</code>
 +
| Description of RPiGPIO Expander device
 +
|-
 +
|colspan="2"|&nbsp;
 +
|-
 +
| <code>RPIGPIOEXP_GPIO_MIN_PIN = GPIO_PIN_0;</code>
 +
| &nbsp;
 +
|-
 +
| <code>RPIGPIOEXP_GPIO_MAX_PIN = GPIO_PIN_7;</code>
 +
| &nbsp;
 +
|-
 +
|colspan="2"|&nbsp;
 +
|-
 +
| <code>RPIGPIOEXP_GPIO_PIN_COUNT = 8;</code>
 +
| &nbsp;
 +
|-
 +
|colspan="2"|&nbsp;
 +
|-
 +
| <code>RPIGPIOEXP_GPIO_PIN_OFFSET = 128;</code>
 +
| &nbsp;
 +
|-
 +
|colspan="2"|&nbsp;
 +
|-
 +
| <code>RPIGPIOEXP_GPIO_MAX_LEVEL = GPIO_LEVEL_HIGH;</code>
 +
| &nbsp;
 +
|-
 +
|colspan="2"|&nbsp;
 +
|-
 +
| <code>RPIGPIOEXP_GPIO_MAX_PULL = GPIO_PULL_DOWN;</code>
 +
| &nbsp;
 +
|-
 +
|colspan="2"|&nbsp;
 +
|-
 +
| <code>RPIGPIOEXP_GPIO_MIN_FUNCTION = GPIO_FUNCTION_IN;</code>
 +
| &nbsp;
 +
|-
 +
| <code>RPIGPIOEXP_GPIO_MAX_FUNCTION = GPIO_FUNCTION_OUT;</code>
 +
| &nbsp;
 +
|-
 +
|}
 +
</div></div>
 +
<br />
  
 
=== Type definitions ===
 
=== Type definitions ===
 
----
 
----
  
−
''To be documented''
+
 
 +
'''RPiGPIO expander specific types'''
 +
 
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial;">
 +
<code>PRPiGPIOExpander = ^TRPiGPIOExpander;</code>
 +
 
 +
<code>TRPiGPIOExpander = record</code>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
|colspan="2"|''GPIO Properties''
 +
|-
 +
| <code>GPIO:TGPIODevice;</code>
 +
| style="width: 50%;"|&nbsp;
 +
|-
 +
|colspan="2"|''RPiGPIO Expander Properties''
 +
|-
 +
| &nbsp;
 +
| &nbsp;
 +
|-
 +
|}
 +
</div></div>
 +
<br />
  
 
=== Public variables ===
 
=== Public variables ===
Line 25: Line 130:
 
----
 
----
  
−
''To be documented''
 
  
 +
'''Initialization functions'''
 +
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">procedure RPiGPIOExpanderInit;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Initialize the RPiGPIO Expander unit and create, register and start the device</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| Called only during system startup
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
 +
'''RPiGPIO expander GPIO functions'''
 +
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderStart(GPIO:PGPIODevice):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Implementation of GPIODeviceStart API for RPiGPIO Expander</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| Not intended to be called directly by applications, use GPIODeviceStart instead.
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderStop(GPIO:PGPIODevice):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Implementation of GPIODeviceStop API for RPiGPIO Expander</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| Not intended to be called directly by applications, use GPIODeviceStop instead.
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderInputGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Implementation of GPIODeviceInputGet API for RPiGPIO Expander</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| Not intended to be called directly by applications, use GPIODeviceInputGet instead.
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderOutputSet(GPIO:PGPIODevice; Pin,Level:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Implementation of GPIODeviceOutputSet API for RPiGPIO Expander</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| Not intended to be called directly by applications, use GPIODeviceOutputSet instead.
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderPullGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Implementation of GPIODevicePullGet API for RPiGPIO Expander</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| Not intended to be called directly by applications, use GPIODevicePullGet instead.
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderPullSelect(GPIO:PGPIODevice; Pin,Mode:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Implementation of GPIODevicePullSelect API for RPiGPIO Expander</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| Not intended to be called directly by applications, use GPIODevicePullSelect instead.
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderFunctionGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Implementation of GPIODeviceFunctionGet API for RPiGPIO Expander</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| Not intended to be called directly by applications, use GPIODeviceFunctionGet instead.
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderFunctionSelect(GPIO:PGPIODevice; Pin,Mode:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Implementation of GPIODeviceFunctionSelect API for RPiGPIO Expander</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| Not intended to be called directly by applications, use GPIODeviceFunctionSelect instead.
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
 +
'''RTL virtual GPIO functions'''
 +
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function SysVirtualGPIOInputGet(Pin:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Get the current state of a virtual GPIO input pin</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Pin
 +
| The pin to get the state for (eg VIRTUAL_GPIO_PIN_1)
 +
|-
 +
! Return
 +
| The current state (eg GPIO_LEVEL_HIGH) or GPIO_LEVEL_UNKNOWN on failure
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function SysVirtualGPIOOutputSet(Pin,Level:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Set the state of a virtual GPIO output pin</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Pin
 +
| The pin to set the state for (eg GPIO_PIN_1)
 +
|-
 +
! Level
 +
| The state to set the pin to (eg GPIO_LEVEL_HIGH)
 +
|-
 +
! Return
 +
| ERROR_SUCCESS if completed successfully or another error code on failure
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function SysVirtualGPIOFunctionGet(Pin:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Get the current function of a virtual GPIO pin</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Pin
 +
| The pin to get the function for (eg GPIO_PIN_1)
 +
|-
 +
! Return
 +
| The current function of the pin (eg GPIO_FUNCTION_IN) or GPIO_FUNCTION_UNKNOWN on failure
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function SysVirtualGPIOFunctionSelect(Pin,Mode:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Change the function of a virtual GPIO pin</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Pin
 +
| The pin to change the function for (eg GPIO_PIN_1)
 +
|-
 +
! Mode
 +
| The function to set for the pin (eg GPIO_FUNCTION_OUT)
 +
|-
 +
! Return
 +
| ERROR_SUCCESS if completed successfully or another error code on failure
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
 +
'''RPiGPIO expander helper functions'''
 +
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderGetState(GPIO:LongWord; var State:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Raspberry Pi Firmware Mailbox call for Get GPIO State</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| None documented
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderSetState(GPIO,State:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Raspberry Pi Firmware Mailbox call for Set GPIO State</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| None documented
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderGetConfig(GPIO:LongWord; var Direction,Polarity,Terminator,PullUp:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Raspberry Pi Firmware Mailbox call for Get GPIO Config</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| None documented
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function RPiGPIOExpanderSetConfig(GPIO,Direction,Polarity,Terminator,PullUp,State:LongWord):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Raspberry Pi Firmware Mailbox call for Set GPIO Config</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! Note
 +
| None documented
 +
|-
 +
|}
 +
</div></div>
 +
<br />
  
 
Return to [[Unit_Reference|Unit Reference]]
 
Return to [[Unit_Reference|Unit Reference]]

Latest revision as of 05:19, 17 June 2021

Return to Unit Reference


Description

Raspberry Pi Firmware GPIO Expander Driver unit

As of February 2017 the Raspberry Pi firmware contains a mailbox interface to allow control of the GPIO expander on the Raspberry Pi 3/4 and Compute Module 3/4.

Unlike the earlier virtual GPIO interface this mailbox service now supports most GPIO functionality including getting and setting a pin value, getting and changing the pin function and getting or changing the pull up/down options.

This driver implements most of the functionality available in the new mailbox service as a standard Ultibo GPIO device and also provides direct mailbox calls to allow access to any additional options not covered by the GPIO device API.

When included in a project this driver replaces the Virtual GPIO functions provided by the PlatformRPi2, PlatformRPi3, PlatformRPi4 units.

According to /arch/arm/boot/dts/bcm2710-rpi-3-b.dts the following pin assignments are known:

  • GPIO_PIN_2 = Activity LED
  • GPIO_PIN_4 = HDMI Detect (Input / Active Low)
  • GPIO_PIN_7 = Power LED (Input / Active Low)

For the Raspberry Pi 3B+ the assignments shown in /arch/arm/boot/dts/bcm2710-rpi-3-b.dts have changed as follows:

  • GPIO_PIN_2 = Power LED (Active Low)
  • GPIO_PIN_4 = HDMI Detect (Input / Active Low)

For the Raspberry Pi 4B the assignments shown in /arch/arm/boot/dts/bcm2711-rpi-4-b.dts are:

  • GPIO_PIN_0 = Bluetooth Power (Active High) (BT_ON)
  • GPIO_PIN_1 = WiFi Power Sequencer (Active Low) (WL_ON)
  • GPIO_PIN_2 = Power LED (Active Low) (PWR_LED_OFF)
  • GPIO_PIN_3 = (GLOBAL_RESET) (ANT1 on CM4)
  • GPIO_PIN_4 = SDIO 1.8V regulator (Active High) (VDD_SD_IO_SEL)
  • GPIO_PIN_5 = CAM1 regulator (Active High) (CAM_GPIO)
  • GPIO_PIN_6 = SD VCC regulator (Active High) (SD_PWR_ON)
  • GPIO_PIN_7 = (SD_OC_N) (ANT2 on CM4)

The Pi 400 and CM4 files at bcm2711-rpi-400.dts and bcm2711-rpi-cm4.dts show identical assignments as the Pi 4B.

Note that this driver requires recent firmware (later than February 2017) and has been tested successfully with the firmware release from 8 October 2020.

The latest version of the firmware is available from https://github.com/raspberrypi/firmware

Constants


RPiGPIO expander specific constants RPIGPIOEXP_GPIO_*
RPIGPIOEXP_GPIO_DESCRIPTION = 'Raspberry Pi Firmware GPIO Expander'; Description of RPiGPIO Expander device
 
RPIGPIOEXP_GPIO_MIN_PIN = GPIO_PIN_0;  
RPIGPIOEXP_GPIO_MAX_PIN = GPIO_PIN_7;  
 
RPIGPIOEXP_GPIO_PIN_COUNT = 8;  
 
RPIGPIOEXP_GPIO_PIN_OFFSET = 128;  
 
RPIGPIOEXP_GPIO_MAX_LEVEL = GPIO_LEVEL_HIGH;  
 
RPIGPIOEXP_GPIO_MAX_PULL = GPIO_PULL_DOWN;  
 
RPIGPIOEXP_GPIO_MIN_FUNCTION = GPIO_FUNCTION_IN;  
RPIGPIOEXP_GPIO_MAX_FUNCTION = GPIO_FUNCTION_OUT;  


Type definitions


RPiGPIO expander specific types

PRPiGPIOExpander = ^TRPiGPIOExpander;

TRPiGPIOExpander = record

GPIO Properties
GPIO:TGPIODevice;  
RPiGPIO Expander Properties
   


Public variables

None defined

Function declarations


Initialization functions 

procedure RPiGPIOExpanderInit;
Description: Initialize the RPiGPIO Expander unit and create, register and start the device
Note Called only during system startup


RPiGPIO expander GPIO functions 

function RPiGPIOExpanderStart(GPIO:PGPIODevice):LongWord;
Description: Implementation of GPIODeviceStart API for RPiGPIO Expander
Note Not intended to be called directly by applications, use GPIODeviceStart instead. 


function RPiGPIOExpanderStop(GPIO:PGPIODevice):LongWord;
Description: Implementation of GPIODeviceStop API for RPiGPIO Expander
Note Not intended to be called directly by applications, use GPIODeviceStop instead. 


function RPiGPIOExpanderInputGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;
Description: Implementation of GPIODeviceInputGet API for RPiGPIO Expander
Note Not intended to be called directly by applications, use GPIODeviceInputGet instead. 


function RPiGPIOExpanderOutputSet(GPIO:PGPIODevice; Pin,Level:LongWord):LongWord;
Description: Implementation of GPIODeviceOutputSet API for RPiGPIO Expander
Note Not intended to be called directly by applications, use GPIODeviceOutputSet instead. 


function RPiGPIOExpanderPullGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;
Description: Implementation of GPIODevicePullGet API for RPiGPIO Expander
Note Not intended to be called directly by applications, use GPIODevicePullGet instead. 


function RPiGPIOExpanderPullSelect(GPIO:PGPIODevice; Pin,Mode:LongWord):LongWord;
Description: Implementation of GPIODevicePullSelect API for RPiGPIO Expander
Note Not intended to be called directly by applications, use GPIODevicePullSelect instead. 


function RPiGPIOExpanderFunctionGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;
Description: Implementation of GPIODeviceFunctionGet API for RPiGPIO Expander
Note Not intended to be called directly by applications, use GPIODeviceFunctionGet instead. 


function RPiGPIOExpanderFunctionSelect(GPIO:PGPIODevice; Pin,Mode:LongWord):LongWord;
Description: Implementation of GPIODeviceFunctionSelect API for RPiGPIO Expander
Note Not intended to be called directly by applications, use GPIODeviceFunctionSelect instead.


RTL virtual GPIO functions 

function SysVirtualGPIOInputGet(Pin:LongWord):LongWord;
Description: Get the current state of a virtual GPIO input pin
Pin The pin to get the state for (eg VIRTUAL_GPIO_PIN_1)
Return The current state (eg GPIO_LEVEL_HIGH) or GPIO_LEVEL_UNKNOWN on failure 


function SysVirtualGPIOOutputSet(Pin,Level:LongWord):LongWord;
Description: Set the state of a virtual GPIO output pin
Pin The pin to set the state for (eg GPIO_PIN_1)
Level The state to set the pin to (eg GPIO_LEVEL_HIGH)
Return ERROR_SUCCESS if completed successfully or another error code on failure 


function SysVirtualGPIOFunctionGet(Pin:LongWord):LongWord;
Description: Get the current function of a virtual GPIO pin
Pin The pin to get the function for (eg GPIO_PIN_1)
Return The current function of the pin (eg GPIO_FUNCTION_IN) or GPIO_FUNCTION_UNKNOWN on failure 


function SysVirtualGPIOFunctionSelect(Pin,Mode:LongWord):LongWord;
Description: Change the function of a virtual GPIO pin
Pin The pin to change the function for (eg GPIO_PIN_1)
Mode The function to set for the pin (eg GPIO_FUNCTION_OUT)
Return ERROR_SUCCESS if completed successfully or another error code on failure


RPiGPIO expander helper functions 

function RPiGPIOExpanderGetState(GPIO:LongWord; var State:LongWord):LongWord;
Description: Raspberry Pi Firmware Mailbox call for Get GPIO State
Note None documented 


function RPiGPIOExpanderSetState(GPIO,State:LongWord):LongWord;
Description: Raspberry Pi Firmware Mailbox call for Set GPIO State
Note None documented 


function RPiGPIOExpanderGetConfig(GPIO:LongWord; var Direction,Polarity,Terminator,PullUp:LongWord):LongWord;
Description: Raspberry Pi Firmware Mailbox call for Get GPIO Config
Note None documented 


function RPiGPIOExpanderSetConfig(GPIO,Direction,Polarity,Terminator,PullUp,State:LongWord):LongWord;
Description: Raspberry Pi Firmware Mailbox call for Set GPIO Config
Note None documented


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