3.2" SPI LCD (working and ready for a build)

[HoolyHoo]

Yeah that looks much better, you can see his little feet going like mad now!

You can add debug=32 at the end of your config, then if you ssh in, a quick dmesg will show you the calculated FPS that the screen is getting (how long each screen update is taking). I would say take it back out if the config once your done, save spamming the system logs

just so that i know i doing it correctly.....

added debug=32 to the end of the config....
did dmesg....

is this what im meant to have seen....




i'm not 100% certain, so apologies for the noob questioning....

.

Are you sure you added it to the contents of this file?

Code: Select all

/etc/modprobe.d/fbtft.conf 

[VeteranGamer]

Are you sure you added it to the contents of this file?

Code: Select all

/etc/modprobe.d/fbtft.conf 

i did, but didnt do a reboot.....

just did it again

[HoolyHoo]

You should see a flood of messages displaying the FPS when you type dmesg at the command line if you entered it correctly.

[VeteranGamer]

You should see a flood of messages displaying the FPS when you type dmesg at the command line if you entered it correctly.

ok.... re-ran the test and this is what i got......

in the emulationstation menu


while running SMW on the SNES



now its showing around 30fps (both times) .... but the games dont seem that slow (if at all)
and i am aware alot of 16bit or lower games dont actually need 60fps to run smoothly

even though its not 60fps (which wasnt expected)....
to my novice eyes this still seems very viable (maybe not ideal)

it would also be interesting to see if the mintyPi setup gives different results, with it being a small screen does it perform better/same/worse


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[codeman0624]

now its showing around 30fps (both times) .... but the games dont seem that slow (if at all)
and i am aware alot of 16bit or lower games dont actually need 60fps to run smoothly

even though its not 60fps (which wasnt expected)....
to my novice eyes this still seems very viable (maybe not ideal)

it would also be interesting to see if the mintyPi setup gives different results, with it being a small screen does it perform better/same/worse


.

This is very cool to be able to see the actual FPS!

You still have the speed setting at 99000000, right? I would be very interested in seeing if the FPS you just measured would go up if you set core_freq=300 in config.txt. This should increase your actual SPI frequency, and maybe increase the FPS

The minty pi should have the same results. It's the same number of pixels, just in a smaller screen size. So the FPS should be the same since it really only depends on pixel count and SPI speed

[VeteranGamer]

This is very cool to be able to see the actual FPS!

You still have the speed setting at 99000000, right? I would be very interested in seeing if the FPS you just measured would go up if you set core_freq=300 in config.txt. This should increase your actual SPI frequency, and maybe increase the FPS

The minty pi should have the same results. It's the same number of pixels, just in a smaller screen size. So the FPS should be the same since it really only depends on pixel count and SPI speed

still have the speed set to 99000000 (which i doubt i will change).....



and i havent tinkered with anything else......

so far, so good (IMHO)......
for me this screen looks like a goer.... if compared to the BW screen, i think its a no brainer (again IMHO)
and if it performs the same as the mintyPi, its another reason... i havent seen people complaining about the perforance on those

when i come to starting my next build i'm gonna start having a look at other settings and see if tweaking here and there ups anything

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[penguinsfan16]

anyone have a link to the red board in the 3rd picture??

[VeteranGamer]

anyone have a link to the red board in the 3rd picture??

that red board is from a 2.4" screen, which i used the screen in my TintyPi build.....

you can use one of these designed by moosepr.....



https://oshpark.com/shared_projects/zUNmnlLF


read his guide....
viewtopic.php?f=22&t=2312


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[moosepr]

30fps isnt too shabby, especially for such a cheap and simple screen setup. If you nudge the speed up any further, you will just get crazy screen. This is what happens if i do speed=100000000


@codeman0624 has done some digging and found the actual spi speed you get is actually linked to the core frequency of the pi, so you are limited to the speeds that actually make an impact on standard installs. Overclocking the pi will mean that you get a higher clock speed, and so in turn a faster spi bus, and as a result, higher FPS

So some things I learned about SPI screens over the weekend:

To get overscan to work, you need to have it enabled (obviously), but you also need to set overscan_scale=1. This may be set by default, but on my system it was not.

The SPI clock speed does not match the requested speed in the settings. The clock frequency depends directly on the core frequency of the chip. And the core frequency is only divisible by powers of 2. Mine seemed to like its core frequency at 250MHz, which means the only available SPI clock frequencies are 125MHz, 62.5MHz, 31.25MHz, 15.625MHz...etc. So dividing 250MHz by 2, 4, 8, 16, etc.

This was confirmed on an oscilloscope. The SPI clock stayed at 62.5MHz for speed settings of 70000000, and 110000000...it did not change because the core frequency divider was always rounded to 4. When I tried 125000000, I actually got a clock frequency of 125MHz, but the screen was very unhappy.

At 62.5MHz the screen has a pretty decent refresh rate, it's relatively smooth. But I was able to get it to run at 75MHz by setting core_freq=300 in config.txt. Adding this extra 12.5MHz made it look even better, I'm quite happy with the final result.

[tinkerBOY]

That is the FPS being output to the framebuffer, but FBTFT/FBCP reads FROM that framebuffer as fast as it can, so that FPS isn't what you're actually seeing.. you need to know the FPS that FBTFT/FBCP is able to write to the screen which will be a lot less. You will see 60fps on HDMI though and if you put side by side you'll see that they are quite different in terms of FPS

Im getting a 60fps too when i tried a 2.2" spi screen but obviously not 60fps at all.

how do you know your getting 60FPS.....

Show video framerate on the retroarch setting when playing a game.