Reference (PiFace CAD)

pifacecad.core

class pifacecad.core.PiFaceCAD(hardware_addr=0, bus=0, chip_select=1, init_board=True)

A PiFace Control and Display board.

Attribute :switch_port – See pifacecommon.mcp23s17.MCP23S17RegisterNeg. Attribute :switches – list containing pifacecommon.mcp23s17.MCP23S17RegisterBitNeg. Attribute :lcd – See pifacecad.lcd.PiFaceLCD.

Example:

>>> cad = pifacecad.PiFaceCAD()
>>> hex(cad.switch_port.value)
0x02
>>> cad.switches[1].value
1
>>> cad.lcd.write("Hello, PiFaceLCD!")
>>> cad.lcd.backlight_on()

class pifacecad.core.SwitchEventListener(chip=None)

Listens for events on the switches and calls the mapped callback functions.

>>> def print_flag(event):
...     print(event.interrupt_flag)
...
>>> listener = pifacecad.SwitchEventListener()
>>> listener.register(0, pifacecad.IODIR_ON, print_flag)
>>> listener.activate()

pifacecad.ir

class pifacecad.ir.IREvent(ir_code)

An IR event.

class pifacecad.ir.IREventListener(prog, lircrc=None)

Listens for IR events and calls the registered functions. prog specifies

>>> def print_ir_code(event):
...     print(event.ir_code)
...
>>> listener = pifacecad.IREventListener(prog="myprogram")
>>> listener.register('one', print_ir_code)
>>> listener.activate()

activate()

When activated the IREventListener will run callbacks associated with IR codes.

deactivate()

When deactivated the IREventListener will not run anything.

register(ir_code, callback)

Registers an ir_code to a callback function.

Parameters:

• ir_code (int) – The IR code.
• callback (function) – The function to run when event is detected.

class pifacecad.ir.IRFunctionMap(ir_code, callback)

Maps an IR code to callback function.

pifacecad.ir.watch_ir_events(event_queue)

Waits for IR code events and places them on the event queue.

Parameters:event_queue (multiprocessing.Queue) – A queue to put events on.

pifacecad.lcd

class pifacecad.lcd.HD44780ControlPort(chip)

Control Port for an HD44780 LCD display. Must have the following properties:

• backlight_pin
• read_write_pin
• register_select_pin
• enable_pin

class pifacecad.lcd.HD44780DataPort(chip)

Data Port for an HD44780 LCD display. Must have the following properties:

• value

class pifacecad.lcd.HD44780LCD(control_port, data_port, init_lcd=True)

Component part of an HD4780, must be combined with a 4 or 8 bit mixin.

backlight_off()

Turn on the backlight.

backlight_on()

Turn on the backlight.

blink_off()

Turns off the blinking cursor.

blink_on()

Turns on the blinking cursor.

char_bank_in_range_or_error(char_bank)

Raises an exception if char_bank is out of bounds. Returns True otherwise.

Parameters:char_bank (int) – The address to check.

clear()

Clears the display.

colrow2address(col, row)

Returns address of column and row.

Parameters:

• col – The column.
• col – int
• row – The row.
• row – int

Returns:

The address of the column and row.

cursor_off()

Turns the underline cursor off.

cursor_on()

Turns the underline cursor on.

display_off()

Turns the display off (quickly).

display_on()

Turns the display on (quickly).

get_cursor()

Returns the current column and row of the cursor. Also fixes internal value.

Returns:(int, int) – A tuple containing the column and row.

home()

Moves the cursor to the home position.

left_justify()

Left justifies text from the cursor.

left_to_right()

Sets the text to flow from left to right.

move_left()

Scrolls the display without changing the RAM.

move_right()

Scrolls the display without changing the RAM.

pulse_clock()

Pulse the LCD clock for reading data.

right_justify()

Right justifies text from the cursor.

right_to_left()

Sets the text to flow from right to left.

see_cursor(col=None)

Moves the viewport so that the cursor is visible.

send_command(command)

Send command byte to LCD.

Parameters:command (int) – The command byte to be sent.

send_data(data)

Send data byte to LCD.

Parameters:data (int) – The data byte to be sent.

set_cgram_address(address=0)

Start using CGRAM at the given address.

Parameters:address (int) – The address to start at (default: 0)

set_cursor(col, row)

Places the cursor at the specified column and row.

Parameters:

• col (int) – The column.
• row (int) – The row.

set_ddram_address(address=None)

Start using DDRAM at the given address.

Parameters:address (int) – The address to start at (default: current)

store_custom_bitmap(char_bank, bitmap)

Stores a custom bitmap bitmap at char_bank.

Parameters:

• char_bank (int) – The CGRAM address to use.
• bitmap (LCDBitmap) – The bitmap to store.

update_display_control()

Update the display control to reflect the displaycontrol.

update_entry_mode()

Update entrymodeset to reflect the displaymode.

update_function_set()

Updates the function set to reflect the current displayfunction.

viewport_corner

The top left corner of the current viewport.

write(text)

Writes a string to the LCD screen.

Parameters:text (string) – The text that will be written.

class pifacecad.lcd.LCDBitmap(lines=[])

A custom bitmap for the LCD screen.

class pifacecad.lcd.PiFaceLCD(control_port, data_port, init_lcd=True)

An HD44780 LCD in 4-bit mode.