Iām sorry that you couldnāt afford a MAKERbuino kit for yourself. You couldāve reached out and I might have given you a discount
Anyways, congratulations on a cool build!
This looks like your microcontroller is resetting due to power supply issues (brownout).
The power supply that youāre using looks like a micro USB cable which is 5V.
You need a 3.3V output, but the LM317 needs 3V of bedroom to operate properly.
That means that you either need a microcontroller with a lower dropout voltage or you need to deliver a minimum of 3.3V+3V=6.3V in order for it to work properly.
Wow! I didnāt expect anyone to reply so soon, but from the creator himself, I am truly grateful.
I already copied your schematics and I donāt want to abuse your kindness by taking you up on your offer of giving me a discount knowing that people who bought this kit paid full price or more. I just want this thing to work like it should. But thanks, anyways.
So I did what you advised, but unfortunately, it still gave me the same results. Iāve read the datasheets for the lm317t, and it said that the voltage difference between input and output should be 5v. So I followed through. The outcome was no different.
There arenāt so many components available locally, so I have to settle with what I can obtain through desoldering scraps from old radios and electronics.
Perhaps the only way I can play games on this is to directly upload the code to the microcontroller. Guess Iāll try that.
Hi,
Iāve encountered this problem before (it resets when I press c) when I built my own gamebuino (before the actual one arrived) and I discovered it was because the bootloader was not flashed.
Maybe you could check if the bootloader was flashed correctly?
I guess you havent flashed the bootloader because you do not have the ICSP headerā¦
@YEA, congrats on building your own MAKERbuino as well and thanks for supporting the project
I agree, that might be the case here. I first though it was connected to the power supply isues, but not having a bootloader will have this effect here
Itās a new microcontroller that I bought. Maybe thatās all thatās missing. Iāll try to burn the bootloader with another arduino by following their instructions online. I highly appreciate the reponses.
Hello, Albert
Can you share more information of that investigation? I am using buck-boost converter (with no filter) instead of LDO, which gives 3.3v Ā± 50mV ripple at 5kHz, and expereincing the same issue with unit rebooting. So I am wondering, what are the requirements for the voltage stability and level, in case that was the issue you discovered.
Funny thing is - arduino ide has a builtin SD example sketch, which works fine, showing SD capacity (1GB), vendor code, etc.
Buckboost IC is TPS63031, rated max 800mA.
Fusebits have BOD disabled.
Thank you.
EDIT: adding HUGE low pass filter 470uH+1500uF gave no effect. This eradicated standby ripple completely, but I was still getting -50mV drop at the moment controller initializes card.
Next thing, I swaped buck-boost IC with 1117 LDO - this gave -20mV drop at initialization, but the thing still reboots. What the hell
ummā¦ I am not sure which information youāre talking about, but Iād recommend sharing a schematic and some photos of your design and maybe Iāll be able to help you from there
Thank you for replying so quickly.
The info I am interested in - what was the evidence that made you conclude LM317 (LDO Budoy_ness used) was the root of the problem, and why it was incompatible in general. It is rated 1.25A, so why not?
I donāt have a schematic, here is my pcb. I know, it is not much of a help)
EDIT: Nailed it, it was a bootloader issue! Reflashing it did the trick.
By the way, is gamebuino_boot.hex, built 30.12.2016, the latest version? Iāve got mine here
The problem for LM317 is that it requires 3V of headroom (VI ā VO) to operate in regulation. This means that if you want an output of 3V, you need an input of 6.3V and the battery used on MAKERbuino only has 3.7V of nominal voltage.
Btw nice PCB. Woah, your vias are huge, you can try making them smaller, you know
Those huge vias are for buttonsā leads, but leads are shortened in order to not come out this side to puncture the battery. Other vias are 0.3mm.
As for LM317 - agree, not suitable for lithium battery, but dropout voltage is not constant 3v. I would say, you could barely make it to 3.3 output on 5v input
Back to the bootloader. Can you please pinpoint the link to the latest version?
Iāhave also found this bootloader, worked for me. It is 2K size, so fusebits must be set L:FF H:D8. Anyone else encountering bootloader stuck in āflashing loaderā state - check your SD is <2G size, has no errors, formatted FAT(16) and LOADER.HEX is present on it.
Always check your fusebits and remember that arduinoās stock bootloader is incompatible with gamebuino.
Hi. Albert! i am trying to make makerbuino from opensource project. I complet almost all steps in building, but i canāt setup any game from sd card. Cardās size is 1 gb (16kb FAT). May be it is some problems with bootloader. Can you give me permission to download a file above?
PLs write how i should download game.HEX in proper way to sd card?
Thanx a lot!)
