Unit RPISENSEHAT

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Description

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Raspberry Pi Sense HAT Driver unit

The Sense HAT 8x8 LED matrix is presented in Ultibo as an 8x8 pixel framebuffer. This allows full access to the display at both the individual pixel level and also using the higher level console functions to display text and graphics on the matrix.

The framebuffer device supports rotation around the full 360 degrees by supplying the required rotation value in the framebuffer properties when calling FramebufferAllocate() or by calling the Sense HAT specific function RPiSenseFramebufferSetRotation().

As per the official Python libraries, the default rotation (FRAMEBUFFER_ROTATION_0) gives correct viewing when the HDMI port is facing downwards.

The Sense HAT joystick appears as a keyboard device and the pressed buttons are received as key presses that represent the Left, Right, Up, Down and Enter keys.

Constants

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RPiSenseHat specific constants RPISENSE_*

RPISENSE_SIGNATURE = $EAEBECED;

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Framebuffer RPISENSE_FRAMEBUFFER_*

RPISENSE_FRAMEBUFFER_DESCRIPTION = 'Raspberry Pi Sense HAT Framebuffer';	Description of RPiSense framebuffer device
RPISENSE_PHYSICAL_WIDTH = 8;
RPISENSE_PHYSICAL_HEIGHT = 8;

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Joystick RPISENSE_JOYSTICK_*

RPISENSE_JOYSTICK_DESCRIPTION = 'Raspberry Pi Sense HAT Joystick';	Description of RPiSense joystick device
RPISENSE_JOYSTICK_KEYMAP:array[0..4] of Word = (
SCAN_CODE_DOWN_ARROW,
SCAN_CODE_RIGHT_ARROW,
SCAN_CODE_UP_ARROW,
SCAN_CODE_ENTER,
SCAN_CODE_LEFT_ARROW

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RPiSenseHat register value RPISENSE_FB*

RPISENSE_FB = $00;
RPISENSE_WAI = $F0;
RPISENSE_VER = $F1;
RPISENSE_KEYS = $F2;
RPISENSE_EE_WP = $F3;

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RPiSenseHat gamma reset value RPISENSE_GAMMA_*

RPISENSE_GAMMA_VALUES_DEFAULT = 0;
RPISENSE_GAMMA_VALUES_LOW = 1;
RPISENSE_GAMMA_VALUES_USER = 2;

Type definitions

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RPi sense

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PRPiSense = ^TRPiSense;

TRPiSense = record

Signature:LongWord;	Signature for entry validation
I2C:PI2CDevice;	I2C device
GPIO:PGPIODevice;	GPIO device
Framebuffer:PFramebufferDevice;	Framebuffer device
Joystick:PKeyboardDevice;	Joystick (Keyboard) device

RPi sense gamma

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PRPiSenseGamma = ^TRPiSenseGamma;

TRPiSenseGamma = array[0..31] of Byte;

RPi sense framebuffer

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PRPiSenseFramebuffer = ^TRPiSenseFramebuffer;

TRPiSenseFramebuffer = record

Framebuffer Properties
Framebuffer:TFramebufferDevice;
RPiSense Properties
I2C:PI2CDevice;	The I2C device the device is connected to
Width:LongWord;	Framebuffer Width in Pixels (Virtual)
Height:LongWord;	Framebuffer Height in Pixels (Virtual)
Rotation:LongWord;	Framebuffer Rotation (eg FRAMEBUFFER_ROTATION_180)
DirtyY1:LongWord;	First line of dirty region (or Height - 1 if none dirty)
DirtyY2:LongWord;	Last line of dirty region (or 0 if none dirty)
Ready:LongBool;	If True timer should be enabled during Mark operation
Blank:LongBool;	If True then display is currently blanked
Lock:TMutexHandle;	Lock for dirty region redraw
Timer:TTimerHandle;	Handle for dirty region redraw timer
FrameRate:LongWord;	Frame rate for display refresh (in Frames Per Second)
Gamma:TRPiSenseGamma;	Current gamma values
GammaUser:TRPiSenseGamma;	User gamma values
PixelData:array[0..63] of Word;	Pixel data for framebuffer update
BlockData:array[0..192] of Byte;	Block data for display update

RPi sense joystick

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PRPiSenseJoystick = ^TRPiSenseJoystick;

TRPiSenseJoystick = record

Keyboard Properties
Keyboard:TKeyboardDevice;
RPiSense Properties
I2C:PI2CDevice;	The I2C device the device is connected to
GPIO:PGPIODevice;	The GPIO device the device is connected to
Pin:LongWord;	The GPIO pin used to signal joystick events (GPIO_PIN_23)
Trigger:LongWord;	The GPIO trigger to detect joystick events (GPIO_TRIGGER_RISING)
PreviousKeys:LongInt;	The keys pressed on the last GPIO event callback
Statistics Properties
CallbackCount:LongWord;	Number of callback requests received by the device

Public variables

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RPiSenseHat specific variables

RPISENSE_I2C_DEVICE:String = 'I2C0';

RPISENSE_GPIO_DEVICE:String = 'GPIO0';

RPISENSE_FRAMEBUFFER_ROTATION:LongWord = FRAMEBUFFER_ROTATION_0;

RPISENSE_FRAMEBUFFER_WIDTH:LongWord = RPISENSE_PHYSICAL_WIDTH;

RPISENSE_FRAMEBUFFER_HEIGHT:LongWord = RPISENSE_PHYSICAL_HEIGHT;

RPISENSE_I2C_ADDRESS:Word = $46;

RPISENSE_LSM9DS1_MAGN_ADDRESS:Word = $1C;

RPISENSE_LSM9DS1_ACCEL_ADDRESS:Word = $6A;

RPISENSE_LPS25H_PRESS_ADDRESS:Word = $5C;

RPISENSE_HTS221_HUMID_ADDRESS:Word = $5F;

Function declarations

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Initialization functions

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procedure RPiSenseInit;

Description: Initialize the RPiSenseHat unit and parameters

Note	Called only during system startup

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function RPiSenseStart(const I2CDevice,GPIODevice:String; Rotation,Width,Height:LongWord):THandle;

Description: Start the RPiSenseHat driver and register the Framebuffer and Joystick devices

I2C	The name of the I2C device that the Sense HAT is connected to
GPIO	The name of the GPIO device that the Sense HAT is connected to
Rotation	The rotation value of the framebuffer (eg FRAMEBUFFER_ROTATION_180)
Width	The width of the framebuffer in pixels (Virtual width only, the Physical width is fixed at 8 pixels)
Height	The height of the framebuffer in pixels (Virtual height only, the Physical height is fixed at 8 pixels)
Return	The handle of the RPiSenseHat on success or INVALID_HANDLE_VALUE on failure
Note	This function will be called during startup if the parameter RPISENSE_AUTOSTART is True

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function RPiSenseStop(Handle:THandle):Boolean;

Description: Stop the RPiSenseHat driver and deregister the Framebuffer and Joystick devices

Handle	The handle of the RPiSenseHat or INVALID_HANDLE_VALUE for the default
Return	True if completed or False on failure

RPiSenseHat framebuffer functions

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function RPiSenseFramebufferCreate(I2C:PI2CDevice; const Name:String; Rotation,Width,Height:LongWord):PFramebufferDevice;

Description: Create, register and allocate a new RPiSenseHat Framebuffer device which can be accessed using the framebuffer API

I2C	The I2C device that the RPiSenseHat is connected to
Name	The text description of this device which will show in the device list (Optional)
Rotation	The rotation value of the framebuffer (eg FRAMEBUFFER_ROTATION_180)
Width	The width of the framebuffer in pixels (Virtual width only, the Physical width is fixed at 8 pixels)
Height	The height of the framebuffer in pixels (Virtual height only, the Physical height is fixed at 8 pixels)
Return	Pointer to the new Framebuffer device or nil if the framebuffer device could not be created

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function RPiSenseFramebufferDestroy(Framebuffer:PFramebufferDevice):LongWord;

Description: Release, deregister and destroy an RPiSenseHat Framebuffer device created by this driver}

Framebuffer	The Framebuffer device to destroy
Return	ERROR_SUCCESS if completed or another error code on failure

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function RPiSenseFramebufferAllocate(Framebuffer:PFramebufferDevice; Properties:PFramebufferProperties):LongWord;

Description: Implementation of FramebufferDeviceAllocate API for RPiSenseHat Framebuffer

Note	Not intended to be called directly by applications, use FramebufferDeviceAllocate instead.

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function RPiSenseFramebufferRelease(Framebuffer:PFramebufferDevice):LongWord;

Description: Implementation of FramebufferDeviceRelease API for RPiSenseHat Framebuffer

Note	Not intended to be called directly by applications, use FramebufferDeviceRelease instead.

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function RPiSenseFramebufferBlank(Framebuffer:PFramebufferDevice; Blank:Boolean):LongWord;

Description: Implementation of FramebufferDevicBlank API for RPiSenseHat Framebuffer

Note	Not intended to be called directly by applications, use FramebufferDevicBlank instead.

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function RPiSenseFramebufferMark(Framebuffer:PFramebufferDevice; X,Y,Width,Height,Flags:LongWord):LongWord;

Description: Implementation of FramebufferDeviceMark API for RPiSenseHat Framebuffer

Note	Not intended to be called directly by applications, use FramebufferDeviceMark instead. Marks full lines only, X and Width are ignored for RPiSenseHat Framebuffer

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function RPiSenseFramebufferCommit(Framebuffer:PFramebufferDevice; Address:PtrUInt; Size,Flags:LongWord):LongWord;

Description: Implementation of FramebufferDeviceCommit API for RPiSenseHat Framebuffer

Note	Not intended to be called directly by applications, use FramebufferDeviceCommit instead.

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function RPiSenseFramebufferSetOffset(Framebuffer:PFramebufferDevice; X,Y:LongWord; Pan:Boolean):LongWord;

Description: Implementation of FramebufferDeviceSetOffset API for RPiSenseHat Framebuffer

Note	Not intended to be called directly by applications, use FramebufferDeviceSetOffset instead.

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function RPiSenseFramebufferGetGamma(Framebuffer:PFramebufferDevice; var Gamma:TRPiSenseGamma):LongWord;

Description: Get the current gamma values from the RPiSenseHat framebuffer

Framebuffer	The Framebuffer device to get from
Gamma	An array of gamma values returned on completion
Return	ERROR_SUCCESS if completed or another error code on failure

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function RPiSenseFramebufferSetGamma(Framebuffer:PFramebufferDevice; const Gamma:TRPiSenseGamma):LongWord;

Description: Set the current gamma values for the RPiSenseHat framebuffer

Framebuffer	The Framebuffer device to set for
Gamma	An array of gamma values to set
Return	ERROR_SUCCESS if completed or another error code on failure

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function RPiSenseFramebufferResetGamma(Framebuffer:PFramebufferDevice; Value:LongWord):LongWord;

Description: Reset the current gamma values for the RPiSenseHat framebuffer to Default, Low or User

Framebuffer	The Framebuffer device to set for
Value	The gamma values to set (0 = Default / 1 = Low / 2 = User)
Return	ERROR_SUCCESS if completed or another error code on failure

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function RPiSenseFramebufferSetRotation(Framebuffer:PFramebufferDevice; Rotation:LongWord):LongWord;

Description: To be documented

Note	None documented

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procedure RPiSenseFramebufferUpdateDisplay(Framebuffer:PRPiSenseFramebuffer);

Description: Timer function for RPiSenseHat framebuffer dirty region redraw

Note	Not intended to be called directly by applications

RPiSenseHat joystick functions

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function RPiSenseJoystickCreate(I2C:PI2CDevice; GPIO:PGPIODevice; const Name:String):PKeyboardDevice;

Description: Create, register and attach a new RPiSenseHat Joystick device which can be accessed using the keyboard API

I2C	The I2C device that the RPiSenseHat is connected to
GPIO	The GPIO device that the RPiSenseHat is connected to
Name	The text description of this device which will show in the device list (Optional)
Return	Pointer to the new Joystick (Keyboard) device or nil if the device could not be created

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function RPiSenseJoystickDestroy(Joystick:PKeyboardDevice):LongWord;

Description: Detach, deregister and destroy a RPiSenseHat Joystick device created by this driver

Joystick	The Joystick (Keyboard) device to destroy
Return	ERROR_SUCCESS if completed or another error code on failure

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procedure RPiSenseJoystickCallback(Joystick:PRPiSenseJoystick; Pin,Trigger:LongWord);

Description: Callback function for the RPiSenseHat Joystick device, called on a worker thread when the registered GPIO event is triggered by a rising edge on the specified pin

Note	Not intended to be called directly by applications

RPiSenseHat helper functions

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function RPiSenseRegRead(I2C:PI2CDevice; Address:Word; Reg:Byte):LongInt;

Description: Read a byte from an RPiSenseHat register

I2C	The I2C device the RPiSenseHat is connected to
Address	The I2C address of the RPiSenseHat
Reg	The register to read
Return	The register value on success or -1 on failure

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function RPiSenseBlockWrite(I2C:PI2CDevice; Address:Word; Data:PByte; Size:Integer):LongWord;

Description: Write a block of data to the RPiSenseHat

I2C	The I2C device the RPiSenseHat is connected to
Address	The I2C address of the RPiSenseHat
Data	Pointer to the data block to be written
Size	Size of the data block in bytes
Return	ERROR_SUCCESS if completed or another error code on failure

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