picodvi – Low-level routines for interacting with PicoDVI Output
Available on these boards
- class picodvi.Framebuffer(width: int, height: int, *, clk_dp: microcontroller.Pin, clk_dn: microcontroller.Pin, red_dp: microcontroller.Pin, red_dn: microcontroller.Pin, green_dp: microcontroller.Pin, green_dn: microcontroller.Pin, blue_dp: microcontroller.Pin, blue_dn: microcontroller.Pin, color_depth: int = 8)
Create a Framebuffer object with the given dimensions. Memory is allocated onto the heap and then moved outside on VM end.
Warning
This may change the system clock speed to match the DVI signal. Make sure to initialize other objects after this one so they account for the changed clock.
This allocates a very large framebuffer and is most likely to succeed the earlier it is attempted.
On RP2040, each dp and dn pair of pins must be neighboring, such as 19 and 20. They must also be ordered the same way. In other words, dp must be less than dn for all pairs or dp must be greater than dn for all pairs.
On RP2350, all pins must be an HSTX output but can be in any order.
The framebuffer pixel format varies depending on color_depth:
1 - Each bit is a pixel. Either white (1) or black (0).
2 - Each two bits is a pixel. Grayscale between white (0x3) and black (0x0).
4 - Each nibble is a pixel in RGB format. The fourth bit is ignored. (RP2350 only)
8 - Each byte is a pixel in RGB332 format.
16 - Each two bytes is a pixel in RGB565 format.
32 - Each four bytes is a pixel in RGB888 format. The top byte is ignored.
Output resolution support varies between the RP2040 and RP2350.
On RP2040, two output resolutions are currently supported, 640x480 and 800x480. Monochrome framebuffers (color_depth=1 or 2) must be full resolution. Color framebuffers must be half resolution (320x240 or 400x240) and pixels will be duplicated to create the signal.
On RP2350, output resolution is either 640x480 or 720x400. Monochrome framebuffers (color_depth=1 or 2) must be full resolution. 4-bit color must also be full resolution. 8-bit color can be quarter, half or full resolution. 16-bit color and 32-bit color must be quarter or half resolution due to internal RAM limitations.
A Framebuffer is often used in conjunction with a
framebufferio.FramebufferDisplay.- Parameters:
width (int) – the width of the source framebuffer. Support varies with chipset.
height (int) – the height of the source framebuffer. Support varies with chipset.
clk_dp (Pin) – the positive clock signal pin
clk_dn (Pin) – the negative clock signal pin
red_dp (Pin) – the positive red signal pin
red_dn (Pin) – the negative red signal pin
green_dp (Pin) – the positive green signal pin
green_dn (Pin) – the negative green signal pin
blue_dp (Pin) – the positive blue signal pin
blue_dn (Pin) – the negative blue signal pin
color_depth (int) – the color depth of the framebuffer in bits. 1, 2 for grayscale and 4 (RP2350 only), 8 or 16 for color, 32 for color (RP2350 only)
- deinit() None
Free the resources (pins, timers, etc.) associated with this
picodvi.Framebufferinstance. After deinitialization, no further operations may be performed.