madctl

Determining the colormode, invert, and rot parameters

The madctl_helper.py program can help determine the colormode, invert, and rot parameters for a display. Set the mosi, clk, dc, cs, backlight, width, and height parameters for your display. Start with rot=0, colormode=COLOR_MODE_RGB, and rot=0. Run the program with the display in the orientation you would like to configure.

Setting the colormode and invert parameter

The program will draw a large red full-screen button with an 'F' character centered in the button. You can determine the colormode and invert parameters by observing the button's color.

• If the button is RED, the colormode and invert parameters are correct.
• If the button is BLUE, colormode should be COLOR_MODE_BGR.
• If the button is YELLOW, invert should be True.
• If the button is CYAN, colormode should be COLOR_MODE_BGR and invert should be True.

Setting the rot parameter

The rot parameter is used to set the MADCTL register of the display. The MADCTL register controls the order that pixels are written to the framebuffer. This sets the Orientation or Rotation of the display. Match the orientation and direction of the 'F' character as drawn on the display by the madctl_helper.py program with the examples in the table below to determine the rot parameter value.

Image	rot parameter
	rot=0
	rot=MADCTL_MY
	rot=MADCTL_MX
	rot=MADCTL_MX | MADCTL_MY
	rot=MADCTL_MV
	rot=MADCTL_MV | MADCTL_MY
	rot=MADCTL_MV | MADCTL_MX
	rot=MADCTL_MV | MADCTL_MX | MADCTL_MX

MADCTL Constants

The following table shows the MADCTL bit flags and their effects.

Constant	Value	Description
MADCTL_MY	0x80	Page Address Order
MADCTL_MX	0x40	Column Address Order
MADCTL_MV	0x20	Page/Column Order
MADCTL_ML	0x10	Line Address Order
MADCTL_MH	0x04	Display Data Latch Order
COLOR_MODE_RGB	0x00	RGB color order
COLOR_MODE_BGR	0x08	BGR color order