How to activate the linux serial console - TheKikGen/MPC-LiveXplore GitHub Wiki
This is to access the internal serial port used for debugging. This induces a disassembly of your MPC, which I do not recommend if you only want to access the internal system. See instead Enabling SSH on the MPC Live X One Force
After my hack to add 4 MIDI OUT on the MPC Live, I went a little further. I plugged a TTL USB serial interface into the main CPU board after opening the case (with a few cold sweats!!!).
MPC USB TTL STICK
----------------------
Ground -> Ground
TX -> RX
RX -> TX
Do not connect the 3.3V or the 5V at all.
You must have a serial terminal emulation on your computer, for example TeraTerm for Windows or Serial or Zterm on MacOSX.
Once the connection is made, you can follow the entire Boot process of the MPC Live, until you get a login prompt.
The "root" user without a password allows you to access the system, and for example to launch some ALSA commands (the Linux audio system).
# amidi -l
Dir Device Name
IO hw:2,0,0 MPC Live Controller MIDI 1
IO hw:2,0,1 MPC Live Controller MIDI 2
IO hw:2,0,2 MPC Live Controller MIDI 3
IO hw:2,0,3 MPC Live Controller MIDI 4
#
# cat /proc/asound/cards
0 [CODEC ]: USB-Audio - USB Audio CODEC
Burr-Brown from TI USB Audio CODEC at usb-ff500000.usb-1.1, full speed
1 [Audio ]: USB-Audio - MPC Live Audio
Akai Professional MPC Live Audio at usb-ff500000.usb-1.5, high speed
2 [Controller ]: USB-Audio - MPC Live Controller
Akai Pro MPC Live Controller at usb-ff500000.usb-1.6, full speed
#
# lsusb -t
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-platform/1p, 480M
|__ Port 1: Dev 2, If 0, Class=, Driver=hub/7p, 480M
|__ Port 1: Dev 3, If 0, Class=, Driver=cdc_acm, 12M
|__ Port 1: Dev 3, If 1, Class=, Driver=cdc_acm, 12M
|__ Port 2: Dev 4, If 0, Class=, Driver=snd-usb-audio, 12M
|__ Port 2: Dev 4, If 1, Class=, Driver=snd-usb-audio, 12M
|__ Port 2: Dev 4, If 2, Class=, Driver=snd-usb-audio, 12M
|__ Port 2: Dev 4, If 3, Class=, Driver=usbhid, 12M
|__ Port 4: Dev 8, If 0, Class=, Driver=uas, 480M
|__ Port 5: Dev 6, If 2, Class=, Driver=snd-usb-audio, 480M
|__ Port 5: Dev 6, If 0, Class=, Driver=snd-usb-audio, 480M
|__ Port 5: Dev 6, If 3, Class=, Driver=, 480M
|__ Port 5: Dev 6, If 1, Class=, Driver=snd-usb-audio, 480M
|__ Port 6: Dev 7, If 0, Class=, Driver=snd-usb-audio, 12M
|__ Port 6: Dev 7, If 1, Class=, Driver=snd-usb-audio, 12M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc2/1p, 480M
#
We can see above that I have connected a Behringer "cheap" usb audio interface that is well detected by the OS but not visible in the MPC software.
I was also able to decode all the MIDI messages of the controller in "internal" mode by snorting the messages with amidi.
This opens up some interesting perspectives!