gdjacobs, do you know if your pi2.7z image is compatible with the raspberry pi 3's cortex a53 cpu? Somewhere I read that pi 2 images on the pi 3 result in a full screen rainbow display. I've just ordered a pi 3 version b and don't think I'll be able to manually upgrade your image to its architecture if it's currently incompatible, because with my pi 1 version b I get a kernel panic and I don't have a pi 2. I'm going to be waiting about a month for it to arrive so, while I do, I'm trying to get everything ready. I saw this page on upgrading a pi 1 to pi 2, and thought the procedure is probably the same for pi 2 to pi 3: https://thepihut.com/blogs/raspberry-pi-tutor … -raspberry-pi-2

Thanks for your hard work! And thanks, too, to PhilsComputerLab for starting this topic. I also have many old machines I could probably just use, but for the sake of simplicity, low-noise, and space savings I plan on using a raspberry pi (& I go way back with GNU/Linux anyway as my preferred OS). If I have to, I'll roll my own raspbian, but will have to wait for the pi 3 to arrive before starting that anyway.

Thanks again,

Lucas

I don't know for sure if my image will be forward compatible as I don't have a Pi 3 to test with. However, the Pi 3 CPU is backwards compatible with the ARMv7 architecture of the Pi 2 while the Pi 1 only supports ARMv6. I wouldn't suspect the original Pi or the Pi Zero to be compatible with something for the Pi 2.

Because it's backwards compatible, perhaps the problems I found are caused by non-cpu related kernel panics (the rainbow overlay for that is obstructive).

To show why I'm concerned, here's one page suggesting problems, but theirs could have been caused by any number of differences from your image: https://www.raspberrypi.org/forums/viewtopic. … 138725&p=926016. Here's another page with that same upgrade process (and more fun stuff): http://www.makeuseof.com/tag/upgrade-raspberry-pi-3/. And, finally, this is probably the page I originally found that got me wondering about compatibility (but it's probably mostly due to their NOOBS install): http://raspberrypi.stackexchange.com/question … -raspberry-pi-3

I'll just have to try it when it arrives; hopefully, I've just worried myself over nothing. The procedure I linked in my previous post says that an image updated with it will be bootable on a pi 2, but will also still work on a pi 1, so I'd expect that to hold true for a pi 3 and pi 2 (unlike the opengl update mentioned on makeuseof.com, but that implies the other updates are still compatible).

Thanks again!

My guess is that the rainbow halt is caused by a change in Videocore. Newer kernels and firmware are supposed to compensate.

You can always use qemu-user-static to chroot the image on a desktop to make changes. Alternately, as you're familiar with Linux, just follow the directions to install MUNT.

Thanks very much for the tip about qemu-user-static! I had no idea one could chroot into another architecture. It's much more friendly than trying to emulate the whole machine in qemu (from what I remember of it), but even that hadn't occurred to me for arm. Though, I guess it makes sense as it's quite a useful trick. I've successfully upgraded your image to jessie, but kept the wheezy collabora mirror on it, since I'm not sure what that was included for. I also chose to unpin the systemd packages it sounds like you hate. Hopefully that wasn't a bad move; I may end up hating systemd too, but I wanted to give it a try since, otherwise, a few packages are held back and it's the new default init system for debian jessie.

I won't be sure it truly boots until I get the new pi in the mail, but at least I've done my due diligence and think I'm prepared now. I'm hesitant to upload it until I know it's perfect, but if someone wants to test it I probably could. There's very slow Internet here, though, so be prepared to wait... and wait for it. 😀

Thanks!

The big thing is to make sure your kernel and firmware are both up to date.

I think they are. Since I can't boot the kernel within a chroot environment (so uname is out of the question), I just checked the installed version of raspberrypi-kernel in aptitude, which is 1.20160620-1, and it's the latest I see at https://github.com/raspberrypi/firmware/releases. That supposedly includes the "raspberry pi kernel and modules, userspace libraries, and bootloader/GPU firmware", so I assume it'll work.

Speaking of the kernel, you just made me realize that you had another partition in that image and that it was the boot partition (partition 1). So, rather than repeat the whole procedure with it mounted at /boot, I moved its contents into /boot.bak, and copied everything from /boot to partition 1 before removing it from partition 2. I'm fairly confident nothing that was already on partition 1, for which there was no replacement from the new /boot on partition 2, will conflict with the new kernel. I don't expect to have problems, but if I do, that will be the first thing I try: removing everything from partition 1, before copying only the pristine new /boot to it. Ah, foolish mistakes... 😉

Well, I've uploaded it for anyone interested. I'm not sure how long I'll leave it up, but feel free to download it while it's available. It did only take last night through to this afternoon to upload it (albeit with nothing else using the connection because it probably would have timed out and needed to be started from scratch otherwise). As said, I don't know if it will work yet, but here it is, gdjacobs' munt raspbian image upgraded to jessie for the pi 3: https://drive.google.com/file/d/0B2uObEBH_jRH … Q-wfF4lSwtS3qPw
Anyone using it will still need to use gdjacobs' method for installing the roms, etc.

Thanks again for everything gdjacobs!

How are you hooking up the Raspberry Pi?

I was thinking to use the 3.3v MIDI output on the Dreamblaster S1 since I already have that and it would save some circuitry, and somehow wiring that up in such a way that I can switch from one to the other. Would that just go into the RX UART pin? Then just hooking up analog audio out to my sound cart line in (or maybe the midi in lines on the waveblaster header)? Is that all I need?

Well, I'm not using a Dreamblaster with the RPi. The MIDI interface is meant to connect with an MPU-401 device so the Pi can receive either GM or LA synthesis command streams from your retro machine.

So you'd still need an MPU-401 or the midi->USB adapter? You can't just use midi TX to logic level converter to RPi RX directly?

The midi TX has to come from somewhere, be it your retro PC sound card or something else.

Yeah so I want to use the midi TX pin on the waveblaster header of my soundcard to connect to the raspberry pi GPIO. I can't just hook that up directly, since it's running at 5V and the RPi uses 3.3, but is the only thing I need a logic level converter? Or do I need something else?

The reason I mentioned the Dreamblaster is that it is already doing 5V midi tx to 3.3 midi tx, and is exposing that for easy access, so if I have everything understood correctly I think I could just wire it from that directly:

You can solve that problem in many different ways without having to carve up your daughterboard. The simplest is to shift your levels 0.7V with a diode.

gdjacobs wrote:

You can solve that problem in many different ways without having to carve up your daughterboard. The simplest is to shift your levels 0.7V with a diode.

...or 1.4 V with 2 diodes, because that will bring it to 3.6V which is close enough to 3.3V
Or a resistive 2/3 divider.

If you do that, your logical zero is going to be outside spec. Also, 3.3V+1.4V=4.7V.

gdjacobs wrote:

If you do that, your logical zero is going to be outside spec. Also, 3.3V+1.4V=4.7V.

Well, yes. We're talking conversion from 5V to 3.3V right?

And vice versa. The RPi RX pin doesn't need anything more than a resistive voltage divider or even a current limiting resistor. If you want to get fancy, you can create transistor buffer circuits. The RPi TX pin can use a diode and a pull up resistor to shift the output up 0.7V, but that also moves up the noise floor.

Has anyone tried using Mac as a General MIDI box? There is a Munt for Mac, so I'm guessing it should be pretty straightforward in that regard, but what kind of software would I need for GM?