[sdiy] Fast lcd display like digitakt
Benjamin Tremblay
btremblay at me.com
Sun Jun 16 14:45:04 CEST 2024
Thanks Brian!
Benjamin Tremblay
> On Jun 15, 2024, at 11:49 PM, brianw <brianw at audiobanshee.com> wrote:
>
> I am not a particular fan of ST Micro (*), but they have a great line of processors that can directly drive parallel LCD modules.
>
> Look at the STM32F series. I recall that there are evaluation boards, but I'm not sure where mine got to in the pile of old demo boards.
>
> The bus can handle at least 24-bit width, but you might end up only needing an 8-bit parallel LCD module. In addition to treating the LCD like fast memory, these chips also have 2D accelerators in the processor that can convert bit depth and colors when blending resources in memory to the display. For example, you could have 1-bit fonts in memory, to save space, but then put the LCD in 8-bit color or 4-bit color mode and have the 2D accelerator handle the format conversion in hardware. I think ST calls this the "ART Accelerator" (Adaptive Real-Time Accelerator).
>
> https://www.st.com/en/microcontrollers-microprocessors/stm32f4-series.html
>
> The catch is that you'll have to graduate from the hobby developer environments and write your own bare metal or RTOS firmware. That is a big step, but it's usually the only way to get maximum performance anyway.
>
> * I have nothing against ST Micro, per se. There are just so many ARM choices out there, and I've already got my favorites. That said, when something they specialize in is needed, I wouldn't hesitate to use ST.
>
> I worked on a project where a single STM32F40x was driving 27 color LCD displays. Yep, twenty-seven of them, and the updates were plenty fast.
>
> Brian Willoughby
>
>
>> On Jun 15, 2024, at 7:36 PM, Benjamin Tremblay wrote:
>> Nope, I made an error. Wasn’t really using spi. Now it runs better.
>> I do think I want to find a larger monochrome display.
>> Benjamin Tremblay
>>
>>> On Jun 15, 2024, at 8:54 PM, Benjamin Tremblay wrote:
>>> I’ve been working on some virtual synth code, and also learning how to send nrpn midi messages. It’s all going well but for midi controller and synth projects I envision a paged Oled display with virtual knob animation and maybe a touchscreen.
>>> What kind of hardware do I need for this? I purchased 2” and 3” displays from Amazon and tried out sample code on an arduino mega and then ran it on a Teensy LC. I have a teensy 4 and a pico and some Stm32F401 boards.
>>> I am using the Adafruit gfx library and so far using an offscreen canvas is too slow.
>>> Should I use a 1-bit display? Repainting the screens is sluggish; maybe 2fps max. Should I use a faster SPI implementation? I know teensy LC is slow. Should I use another graphics library?
>>> I’m going to assume displays are nice for things like waveform editing and such. I have seen some fast oscilloscope demos on Oled displays.
>>> Hm.
>>>
>>> Benjamin Tremblay
>
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