Display performance requirements
phil-barrett opened this issue · comments
What kind of performance do you need from the display? Since you went with a parallel interface, I assume that you need fast updates. There are lots of inexpensive displays that use SPI - too slow for your needs?
By the way, I am posting in Issues though these aren't really "issues". If you turned on Discussions - I would put them there. I think your project has a lot of potential for derivative projects and variant hardware. Perhaps Discussions would be a better place to talk about that?
Display performance was an important part of the design and I went through
a few iterations. SPI would be the easiest since its' supported by DMA
which will allow rendering in memory and sending to the display at the same
time. However, the ILI9488 datasheet specifies max SPI speed of ~15Mhz
which is about 1M pixels/sec. (16 bits each). With the parallel interface
the analyzer archives about 10M pixels/secs, including color mapping from 8
bit pixels in memory (to save RAM) to 16 bit pixels required by the ILI9488.
You are right about the potential for derivative projects, e.g. cutting
cost using a display-less unit that connects to a phone or a computer via
USB (sensors are galvanically isolated so should be safe) or BLE. Another
option is to have a board that supports multiple sensors (e.g. to determine
x/y/z of a delta or corexy printer). You can see this design as a proof of
concept that hopefully inspire ideas and products.
…On Fri, Apr 23, 2021 at 9:13 AM phil-barrett ***@***.***> wrote:
What kind of performance do you need from the display? Since you went with
a parallel interface, I assume that you need fast updates. There are lots
of inexpensive displays that use SPI - too slow for your needs?
By the way, I am posting in Issues though these aren't really "issues". If
you turned on Discussions - I would put them there. I think your project
has a lot of potential for derivative projects and variant hardware.
Perhaps Discussions would be a better place to talk about that?
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FYI, I just released a new design which uses a bare TFT panel and the Raspberry Pi Pico. The screen update rate with that design is 12M pixels/sec which is equivalent to 192Mhz SPI.