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MT32-pi not getting power from USB cable
Posted: Thu Mar 03, 2022 6:01 am
by retro
My MT32-pi is not getting power from the USB cable 
Power is only available when I connect the micro-USB cable to my Raspberry Pi 3B+
I thought the MT32-pi was supposed to be able to draw power from the MiSTer, or am I getting something wrong?
The Digital IO Board, MT32-pi, inline power switch, power supply splitter cable, and 5V4A power supply were all purchased from https://misterfpga.co.uk
The USB cable is the CY black right-angle A-A 20cm cable, which was tested according to https://github.com/dwhinham/mt32-pi/wik ... USB-cables
MT32-pi.cfg is already configured following the documentation in https://github.com/dwhinham/mt32-pi/wik ... -and-usage
Any help and advice would be greatly appreciated 
Re: MT32-pi not getting power from USB cable
Posted: Thu Mar 03, 2022 7:05 am
by Solskogen
Does the MT32-pi work when you connect it to the MiSTer?
Re: MT32-pi not getting power from USB cable
Posted: Thu Mar 03, 2022 7:35 am
by MysteryScience
This looks more like a power supply problem.
Maybe using a Raspberry Pi 3 A+?
Re: MT32-pi not getting power from USB cable
Posted: Thu Mar 03, 2022 10:58 am
by AngelicLiver
Please let us know which Pi model you are using and the (assuming you are using one) the MT32-Pi hat, which model.
This
video may help you with the setup setup. It could be something as simple as your mt32-pi.cfg file needs configuring and/or the switch isn't in the correct position.
Re: MT32-pi not getting power from USB cable
Posted: Fri Mar 04, 2022 1:12 am
by retro
I am using this MT32-pi -->
https://misterfpga.co.uk/product/mister ... i-hat-v2-1
And this is the power supply I am using -->
https://misterfpga.co.uk/product/mister ... wer-supply
I'm using a Raspberry Pi 3B+, and it's the only one I can spare. I have two other Pi 4s, but they are essential parts of my home network, so I can't disconnect them for testing.
I couldn't find a Raspberry Pi 3A, at least not in the secondary market here in Malaysia, and the global Pi scarcity at the moment isn't helping either.
Re: MT32-pi not getting power from USB cable
Posted: Fri Mar 04, 2022 1:14 am
by retro
Solskogen wrote: ↑Thu Mar 03, 2022 7:05 am
Does the MT32-pi work when you connect it to the MiSTer?
Everything works great as long as I have a separate power supply connected to the Raspberry Pi.
However, it's obvious there's no power when I just use the USB cable connected to the MiSTer's Data IO port, as the Pi's red LED doesn't turn on, and the OLED screen on the MT32-pi is blank.
Re: MT32-pi not getting power from USB cable
Posted: Fri Mar 04, 2022 7:56 am
by LamerDeluxe
Since I've added an RGB fan to my MiSTer, it is not able to properly power my MT32-pi anymore. My power supply is a 5A MeanWell, so that's not the problem. I am using an in-line power switch, so that probably doesn't help.
Re: MT32-pi not getting power from USB cable
Posted: Fri Mar 04, 2022 10:38 am
by metalfacemark
have you tried a shorter cable?
Re: MT32-pi not getting power from USB cable
Posted: Mon Mar 07, 2022 1:42 am
by retro
metalfacemark wrote: ↑Fri Mar 04, 2022 10:38 am
have you tried a shorter cable?
The cable is 20cm, I can't find any shorter cable
I believe cable length would only affect data transmission, not power
The cable I am using is one of the tested and recommended cables from the MT32pi GitHub anyway
At this point I am chalking it up to my using a Raspberry Pi 3B+, instead of the preferred 3A board.
Re: MT32-pi not getting power from USB cable
Posted: Mon Mar 07, 2022 6:23 am
by pepito
I had the same problem and I moved to the small MT32 hat with Pi Zero2. (USB3)
I was so disappointed to use dual PSU...
The Digital IO Board is regulated to a limited AMP load, so you won't have the full Amp dedicated from your PSU.
Re: MT32-pi not getting power from USB cable
Posted: Mon Mar 07, 2022 1:40 pm
by flynnsbit
Did you flip the power switch on the MT-32pi? Dumb question but I want to make sure you know the switch on it is a power switch, it's basically there for if you are powering internal, flip one way, external the other.
Re: MT32-pi not getting power from USB cable
Posted: Tue Mar 08, 2022 1:25 am
by retro
flynnsbit wrote: ↑Mon Mar 07, 2022 1:40 pm
Did you flip the power switch on the MT-32pi? Dumb question but I want to make sure you know the switch on it is a power switch, it's basically there for if you are powering internal, flip one way, external the other.
Well, that was dumb of me not to notice the power switch
That fixed the problem, and the MT32-pi was able to draw power via the USB cable.
However, that opened up another problem - the USB hub (see
https://misterfpga.co.uk/product/usb-hu ... ister-fpga) was no longer able to power my 8bitdo M30 controller
The hub has a powered USB port, and it had sufficient juice to power the MT32-pi... but at the expense of the 8bitdo controller again.
Re: MT32-pi not getting power from USB cable
Posted: Tue Mar 08, 2022 1:52 am
by retro
So I did some further reading elsewhere in this forum, and sure enough the problem is with the inline switch.
Upon closer inspection, the inline switch can only output 2A even though my PSU is rated for 4A
Connecting the power directly to the DE10-Nano and USB hub with the splitter allowed the MT32-pi to draw enough power from the USB hub's powered port, even though it still couldn't draw power from the User IO port.
So I guess the next thing to buy is an inline switch that can output 4A, if such a thing exists
Re: MT32-pi not getting power from USB cable
Posted: Tue Mar 08, 2022 2:33 am
by retro
aliexpress.com/item/1005002904567297.html
is this a good enough inline switch? Product description reads 5V-24V 5A
Re: MT32-pi not getting power from USB cable
Posted: Tue Mar 08, 2022 2:56 am
by jca
I wouldn't trust anything from Aliexpress. I also wonder why people want to use a switch on the 5V side where quite a few amps have to be switched, a switch on the primary side (110V/220V) is a much better choice: it just must be rated for the voltage, the amps passing thru such a switch will be ridiculous low.
Re: MT32-pi not getting power from USB cable
Posted: Tue Mar 08, 2022 3:13 am
by retro
jca wrote: ↑Tue Mar 08, 2022 2:56 am
I wouldn't trust anything from Aliexpress. I also wonder why people want to use a switch on the 5V side where quite a few amps have to be switched, a switch on the primary side (110V/220V) is a much better choice: it just must be rated for the voltage, the amps passing thru such a switch will be ridiculous low.
Would you be able to recommend such a switch?
Sorry, i'm not very well versed with electrical items
There isn't much of a choice here in Malaysia outside of AliExpress, as shipping products from Amazon or eBay are prohibitively expensive, especially if it's a small items that's only worth a few dollars.
Re: MT32-pi not getting power from USB cable
Posted: Tue Mar 08, 2022 3:46 am
by Flandango
retro wrote: ↑Tue Mar 08, 2022 3:13 am
Would you be able to recommend such a switch?
Sorry, i'm not very well versed with electrical items
There isn't much of a choice here in Malaysia outside of AliExpress, as shipping products from Amazon or eBay are prohibitively expensive, especially if it's a small items that's only worth a few dollars.
He's referring to a device suck as a Power Strip with an on/off switch. That way you turn on/off "Mains" power to transformer instead of from transformer to Mister.
Re: MT32-pi not getting power from USB cable
Posted: Tue Mar 08, 2022 8:51 am
by retro
Flandango wrote: ↑Tue Mar 08, 2022 3:46 am
He's referring to a device suck as a Power Strip with an on/off switch. That way you turn on/off "Mains" power to transformer instead of from transformer to Mister.
Oh...
Unfortunately that's not possible for my current setup, as the MiSTer is on a power strip that only has a single on/off switch, not individual switches. It's shared with my home router, Pi-hole, and fiber modem (amongst other equipment), so I don't ever turn it off.
But this is a good idea... will look for a power strip with individual switches
Re: MT32-pi not getting power from USB cable
Posted: Tue Mar 08, 2022 9:35 am
by FPGA64
retro wrote: ↑Tue Mar 08, 2022 1:25 am
flynnsbit wrote: ↑Mon Mar 07, 2022 1:40 pm
Did you flip the power switch on the MT-32pi? Dumb question but I want to make sure you know the switch on it is a power switch, it's basically there for if you are powering internal, flip one way, external the other.
Well, that was dumb of me not to notice the power switch
That fixed the problem, and the MT32-pi was able to draw power via the USB cable.
However, that opened up another problem - the USB hub (see
https://misterfpga.co.uk/product/usb-hu ... ister-fpga) was no longer able to power my 8bitdo M30 controller
The hub has a powered USB port, and it had sufficient juice to power the MT32-pi... but at the expense of the 8bitdo controller again.
The hub should not be used to power the MT32 pi. The Pi will draw all its power through the IO port of the Io Board. It doesnt need an external power connection.
The Mt32 stack needs one connection from the Hat to the IO port. Nothing should go to the Pi at all
Re: MT32-pi not getting power from USB cable
Posted: Wed Mar 09, 2022 12:55 am
by retro
FPGA64 wrote: ↑Tue Mar 08, 2022 9:35 am
The hub should not be used to power the MT32 pi. The Pi will draw all its power through the IO port of the Io Board. It doesnt need an external power connection.
The Mt32 stack needs one connection from the Hat to the IO port. Nothing should go to the Pi at all
Unfortunately that never worked for me.
If I am only using the IO port with no external power connection, the OLED on the HAT will flash the MT32pi logo and that's it... it doesn't work beyond that.
Re: MT32-pi not getting power from USB cable
Posted: Wed Mar 09, 2022 8:34 am
by Bunker
retro wrote: ↑Wed Mar 09, 2022 12:55 am
FPGA64 wrote: ↑Tue Mar 08, 2022 9:35 am
The hub should not be used to power the MT32 pi. The Pi will draw all its power through the IO port of the Io Board. It doesnt need an external power connection.
The Mt32 stack needs one connection from the Hat to the IO port. Nothing should go to the Pi at all
Unfortunately that never worked for me.
If I am only using the IO port with no external power connection, the OLED on the HAT will flash the MT32pi logo and that's it... it doesn't work beyond that.
I have the exact same issue as yourself, I need an external power supply of some sort for the MT32pi it also says psu low on the screen.
Re: MT32-pi not getting power from USB cable
Posted: Wed Mar 09, 2022 9:26 am
by FPGA64
if you get the lower power warning then you edit the config files
To do this, edit your config.txt and add the following line above the [pi3] section. This disables the warnings and the throttling:
avoid_warnings=2
note this is not the cfg file that you make the other edits to
https://github.com/dwhinham/mt32-pi/wik ... -and-usage
Re: MT32-pi not getting power from USB cable
Posted: Wed Mar 09, 2022 9:30 am
by Xbytez
Bunker wrote: ↑Wed Mar 09, 2022 8:34 am
it also says psu low on the screen.
Try adding this to your config.txt
The "low voltage" message is triggered by the Raspberry Pi's GPU-based firmware, which will also throttle the CPU when it notices a low voltage condition. This will cause the audio to stutter. This mechanism exists to prevent data loss when using the Raspberry Pi as a computer, but for mt32-pi we should be able to safely disable it.
To do this, edit your config.txt and add the following line above the [pi3] section. This disables the warnings and the throttling:
⚠ Note: Please ensure your Raspberry Pi's CPU is heatsinked, as it's not known if this option disables thermal throttling!
Alternatively, you can cut the +5V connection between MiSTer and Raspberry Pi, and use a dedicated power supply for the Raspberry Pi. If you use the MiSTer HAT, simply turn off the switch to achieve this.
⚠ Note: Make sure you turn off the switch when powering the Raspberry Pi externally. Otherwise, the Pi's PSU will begin powering the MiSTer, resulting in further loss of power to the Pi.
Source:
https://github.com/dwhinham/mt32-pi/wik ... e-warnings
Re: MT32-pi not getting power from USB cable
Posted: Wed Mar 09, 2022 7:39 pm
by Bunker
Thanks for the help will edit the config and try again, i also have the below and i don't have that issue:
https://www.tindie.com/products/taviens ... pberry-pi/
Re: MT32-pi not getting power from USB cable
Posted: Wed Mar 09, 2022 8:31 pm
by FPGA64
Just remember that the power warning is in a different file to the config of thr Mt32 Pi
Re: MT32-pi not getting power from USB cable
Posted: Thu Mar 10, 2022 12:56 am
by retro
Bunker wrote: ↑Wed Mar 09, 2022 8:34 am
I have the exact same issue as yourself, I need an external power supply of some sort for the MT32pi it also says psu low on the screen.
I don't get the same notification on my Pi
I have disabled warnings in MT32pi config files, and I have three heatsinks applied to the three main chips on the Pi3
I have a copper heatsink case coming soon, as my Pi3 is just resting on a piece of acrylic at the moment.
Re: MT32-pi not getting power from USB cable
Posted: Sat Mar 12, 2022 7:01 pm
by LamerDeluxe
I've just bought one of these, instead of using one of those standard inline cable switches:
- stopcontact-schakelaar-stroomsterkte-16-a.jpg (54.32 KiB) Viewed 4833 times
I can now power the mt32-pi from my MiSTer, together with my TTY2OLED and RGB LED fan without any problems.
Re: MT32-pi not getting power from USB cable
Posted: Sat Mar 26, 2022 8:43 am
by SpaceFlightOrange
I've been having similar'ish problems with my setup. got the DE-10, Analogue I/O 1.6 and a USB board stacked in a case, using the same Meanwell supply with a splitter, but I'm using a smart plug with mine rather than an inline switch and it turn it on using my phone. this all works.
but with the MT32-Pi hat on a Pi Zero 2 connected, the MiSTer main menu flashes, it's almost as if the RGB channels are separating and I see parts of the MiSTer wallpaper across the screen in different colours.
I get no low power warning on the MT32-Pi and although it appears to work (I see the VU-meter working on the AO486 core) I get no sound.
I'm confident the flashing issue is power related because I don't see it if I disconnect the MT-32-Pi or power the Pi separately, and the only thing connected to the USB hub is my Logitech Unifying dongle.