04-16-2018, 07:55 AM
(This post was last modified: 04-16-2018, 08:49 AM by wabbit4two.)
I've received the Freeplay Tech CM3 now and have put it together. It's pretty amazing how well this has been designed and thought through. From the perfectly fitting circuit board to the useful software RetroPi hotkeys, this is a great bit of kit.
However, I wish the screen were better. The LCD display lets this build down, and when first using it, was borderline unplayable for me. Especially for a game like Sonic where FPS is important, the screen just didn't seem to be able to keep up.
So I read up on config for the LCD on these forums and online, and edited the relevant lines in /boot/config.txt to:
My understanding is that the speed parameter here relates to the speed of the SPI interface that the LCD uses. The higher the number, the more information is pushed to the LCD. I initially changed this speed from 80000000 to 82000000 as per advice from other forum posts. It made a noticeable improvement. So I kept increasing the speed until I reached the level where it wouldn't go any higher without artifacts appearing on the display.
So now the device is usable for me. However, while the Raspberry Pi CM3 is capable of rendering 60 fps, the display is not running at 60 fps. It's probably closer to 30 fps, maybe 35 ish at a guess. To be clear, the CM3 pushes 60 fps but 60 frames per second are not being rendered by the LCD. I'm guessing that this is a hardware limitation probably with the SPI interface, and I don't know if this interface can actually achieve 60 fps to any LCD.
After reading up on the Raspberry Pi's display interfaces, I stumbled on the DPI interface which is better. It seems that the LCD for Freeplay Tech uses the less capable SPI interface, and therefore there are some hardware limitations with this.
The best display I can find is the PiMoroni HyperPixel. It uses the DPI interface which means it can achieve 60 fps, but the downside is that all of the GPIO pins are used to push the needed info to the display. https://shop.pimoroni.com/products/hyperpixel
I'm assuming that the 40 pin display interface on the Freeplay Tech CM3 board won't support this. Does anyone know for sure? And obviously the display may just be too big for teh gba shell without cutting more of the inside away (and I don't know if it will actually fit with the buttons on either side). Anyone have experience and know if this 3.5" display can fit?
If the above display isn't going to work, what's the best LCD hardware available out there that will fit in a gba shell for a Freeplay tech build? When looking for a replacement LCD that can fit, I'm not so sure that one exists. I think that what we have may be the best thing available.
Now with the change to the config above, the device is now playable for me and I'm excited to get stuck into some games. But I can't help think if there's a better display out there that will make the experience even better than it already is.
Does anyone have any thoughts?
However, I wish the screen were better. The LCD display lets this build down, and when first using it, was borderline unplayable for me. Especially for a game like Sonic where FPS is important, the screen just didn't seem to be able to keep up.
So I read up on config for the LCD on these forums and online, and edited the relevant lines in /boot/config.txt to:
Code:
hdmi_force_hotplug=1
hdmi_cvt=320 240 60 1 0 0 0
hdmi_group=2
hdmi_mode=87
dtparam=spi=on
dtoverlay=waveshare32b:speed=99999999,fps=60,rotate=270My understanding is that the speed parameter here relates to the speed of the SPI interface that the LCD uses. The higher the number, the more information is pushed to the LCD. I initially changed this speed from 80000000 to 82000000 as per advice from other forum posts. It made a noticeable improvement. So I kept increasing the speed until I reached the level where it wouldn't go any higher without artifacts appearing on the display.
So now the device is usable for me. However, while the Raspberry Pi CM3 is capable of rendering 60 fps, the display is not running at 60 fps. It's probably closer to 30 fps, maybe 35 ish at a guess. To be clear, the CM3 pushes 60 fps but 60 frames per second are not being rendered by the LCD. I'm guessing that this is a hardware limitation probably with the SPI interface, and I don't know if this interface can actually achieve 60 fps to any LCD.
After reading up on the Raspberry Pi's display interfaces, I stumbled on the DPI interface which is better. It seems that the LCD for Freeplay Tech uses the less capable SPI interface, and therefore there are some hardware limitations with this.
The best display I can find is the PiMoroni HyperPixel. It uses the DPI interface which means it can achieve 60 fps, but the downside is that all of the GPIO pins are used to push the needed info to the display. https://shop.pimoroni.com/products/hyperpixel
I'm assuming that the 40 pin display interface on the Freeplay Tech CM3 board won't support this. Does anyone know for sure? And obviously the display may just be too big for teh gba shell without cutting more of the inside away (and I don't know if it will actually fit with the buttons on either side). Anyone have experience and know if this 3.5" display can fit?
If the above display isn't going to work, what's the best LCD hardware available out there that will fit in a gba shell for a Freeplay tech build? When looking for a replacement LCD that can fit, I'm not so sure that one exists. I think that what we have may be the best thing available.
Now with the change to the config above, the device is now playable for me and I'm excited to get stuck into some games. But I can't help think if there's a better display out there that will make the experience even better than it already is.
Does anyone have any thoughts?