Getting Started#
Hardware Setup#
The Pisound Micro comes with no header or audio / MIDI connectors pre-soldered, offering maximum flexibility for your project's layout. Whatever way you decide to go is entirely up to you, but we'll share some basic connection schemes to get you going.
Hooking up to Raspberry Pi#
In order to use Pisound Micro with Raspberry Pi, either all or a minimal actually used set of the Raspberry Pi GPIO header pins must make contact between the boards. The pins map one-to-one, meaning that each P01> GPIO pin on Pisound Micro must be connected to the corresponding GPIO pin on the Raspberry Pi. For example, pin 1 on Pisound Micro should be connected to pin 1 on the Raspberry Pi, pin 2 to pin 2, and so on, up to pin 40.
The square hole indicates the very first pin. The pin numbering matches the numbering at pinout.xyz
After making the connections and before powering on, always doublecheck with a multimeter in beeping mode whether there's no unexpected connections.
Mounting on Top#
For mounting Pisound Micro directly on top of the Raspberry Pi, you'll want to use a 2x20 female pin header with 2.54mm (0.1") pitch. You may find 40 pin headers with pins of different lengths (Toby, Male Headers on DigiKey, Female Headers on DigiKey), ones with long pins are useful for adjusting the height of Pisound Micro, like if a fan must fit underneath the Pisound Micro and/or for stacking something on top or making additional connections using female cable jumpers or soldering directly to the protruding pins. You may use headers with short pin length too, as the entire 40 pin GPIO header is duplicated alongside for easy access to the Raspberry Pi GPIOs.
The recommended way of soldering the female pin header is to insert it from the bottom side of Pisound Micro (the bottom side is the one without any electronic components) to the holes marked with P01>, first solder a corner pin, then inspect the header alignment. If any adjustment is needed, reheat the solder, move the header into the correct position, and hold it there until the solder cools down and stiffens back again. Then solder a diagonal corner pin, so the header is secured in a stable position. Continue soldering every pin. If you think you're spending too much time on a single pin, you may want to skip a few pins forward for soldering and come back to the previous location, to avoid overheating the area.
Ribbon Cable Connection#
Another option is to make the connection using a 40 way ribbon cable, connecting each of the 40 GPIO header contacts between the boards. You can acquire cable assemblies with IDC headers preinstalled at certain lengths, or you may even opt to assemble your own cable by cutting the required length of ribbon cable and installing the IDC connectors yourself. Pay attention to the pink line (or otherwise identify your first wire) and the little marking of the first contact on the IDC connector, to ensure all of the connectors are installed the right way. If using a connector, you'll want to install a 2x20 male pin header with 2.54mm (0.1") pitch. The same soldering tips from above section apply here as well, except the header must be inserted from the top side (the one with all the components).
If you'd like, you may decide to solder the ribbon cable's wires directly into the holes without any header.
Before powering on, it's always a good idea to doublecheck the header pins between the boards whether the connections take place between the expected contacts.
Wire Connection#
You may even connect the boards up using regular wires soldered directly into the contact holes or install a header to your liking for use with cable jumpers to link the boards together.
The Pins That Must Be Connected Together
All of the named pins must be hooked up at matching positions between the boards.
| 1. 3.3V Power | 2. 5V Power |
| 3. SDA | 4. 5V Power |
| 5. SCL | 6. GND |
| 7. ... | 8. ... |
| 9. GND | 10. ... |
| 11. ... | 12. PCM CLK |
| 13. ... | 14. GND |
| 15. ... | 16. ... |
| 17. 3.3V Power | 18. ... |
| 19. ... | 20. GND |
| 21. ... | 22. ... |
| 23. ... | 24. ... |
| 25. GND | 26. ... |
| 27. ... | 28. ... |
| 29. ... | 30. GND |
| 31. ... | 32. ... |
| 33. ... | 34. GND |
| 35. PCM FS | 36. GPIO16 |
| 37. GPIO 26 | 38. PCM DIN |
| 39. GND | 40. PCM DOUT |
In case the signal name matches on multiple pins (3.3V Power, 5V Power, GND), you may hook the pin holes to a single carrier cable, and split it out at the other end. Recommended wire gauge is around 26 AWG. Strive for equal and as short as possible cable length, especially for orange and blue wire groups.
Custom PCB#
To build a custom PCB that hosts a Pisound Micro, refer to the mechanical drawing showcasing the key elements, their positions and dimensions - the outline of the board, the mounting holes, and the headers.
Find more details about the drawing here.
Wiring Connectors#
Audio#
The schematic below shows how to hook up audio jacks to Pisound Micro's A header. For more detailed information about each port connection, see Audio Connections. You may hook up only the connectors you plan to use. If you use connectors for input with normally closed contacts, connect AGND to the closed state pins.
Wire color legend:
| Black | Gray | White | Red | Blue | Orange | Green | Purple |
|---|---|---|---|---|---|---|---|
| AGND | VGND | Left Ch. | Right Ch. | Diff. Left- | Diff. Left+ | Diff. Right- | Diff. Right+ |
| Output pins: | A01 | A03 | A04 | A07 | A08 | A09 | A10 |
| Input pins: | N/A | A17 | A18 | A15 | A16 | A13 | A14 |
| Black | Gray | White | Red |
|---|---|---|---|
| AGND | VGND | Left Ch., Out: A03, In: A17 | Right Ch., Out: A04, In: A18 |
| Blue | Orange | Green | Purple |
| Diff. Left-, Out: A07, In: A15 | Diff. Left+, Out: A08, In: A16 | Diff. Right-, Out: A09, In: A13 | Diff. Right+, Out: A10, In: A14 |
MIDI#
You may opt to use DIN-5 MIDI ports, or minijack ports, up to your preference. If using DIN-5, there's only one standard way to connect them:
| Pin Name | Input Port | Output Port |
|---|---|---|
| 2 Shield | (not connected) | GND |
| 4 Source | A22 | A24 |
| 5 Sink | A21 | A23 |
The LEDs on pins A27 (input activity) and A28 (output activity) are optional and can be connected to any Pisound Micro's GPIO pin.
The Activity LED Setup Commands
For completeness though, here's how to make these particular pins output MIDI monitoring signals, assuming you have the kernel module already set up:
echo act_in activity_midi_in A27 > /sys/pisound-micro/setup
echo act_out activity_midi_out A28 > /sys/pisound-micro/setup
Pay attention that the output has a GND connection on its Pin 2 (the middle pin), while Input's Pin 2 is not connected.
If using minijacks, there's 3 ways on how to hook them up, pick one that's suited for the devices you intend to use it with. Our products are using Type A (MIDI Standard). Please refer to this excellent website for wiring diagrams: https://minimidi.world/
Quick Software Setup#
To install the Pisound Micro software on Debian compatible distributions like Raspberry Pi OS or Patchbox OS, open a terminal (command) window and run:
curl https://blokas.io/pisound-micro/install.sh | sh
This will set up the Blokas APT server, install all the software packages for Pisound Micro, load the kernel module, and make the changes in config.txt so the Pisound Micro is ready to go every time the system starts.
Manual Software Setup#
The manual setup process described below accomplishes the same tasks as the automated script above, but broken down into individual steps. This approach is useful if you want more control over the installation process or need to troubleshoot specific components, or gain more understanding on what happens during the Pisound Micro installation.
APT Server Setup#
If you're using an OS image other than Patchbox OS, then do this first:
curl https://blokas.io/apt-setup.sh | sh
It will add our APT server which hosts the debs we built for our products.
Software and Default Configs#
Before loading up the kernel module for Pisound Micro, it's recommended to install the default software and configuration packages:
sudo apt update
sudo apt install pisound-micro
Setting up the Boot Config#
To make the Pisound Micro's kernel driver load automatically on system startup, the
/boot/firmware/config.txt should be modified:
sudo nano /boot/firmware/config.txt
Add the following at the end of the file:
[all]
dtoverlay=pisound-micro
dtparam=i2c_arm=on,i2c_arm_baudrate=400000
This enables the Device Tree overlay for Pisound Micro, as well as enables the I²C bus and sets its speed to 400kHz.
Hit Ctrl+X, then Y to save your changes and exit.
Finally, a reboot is required for changes to take place:
sudo reboot
Verifying it Works#
Once the Initial Setup is complete and the system booted up again, you may check the output of the following commands:
aplay -l
arecord -l
amidi -l
These commands list all the playback, recording and MIDI devices currently available on the system. You should see output similar to:
aplay -l
...
card 3: pisoundmicro [pisoundmicro], device 0: PSM-1234567 adau-hifi-0 [PSM-1234567 adau-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
...
arecord -l
...
card 3: pisoundmicro [pisoundmicro], device 0: PSM-1234567 adau-hifi-0 [PSM-1234567 adau-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
...
amidi -l
...
IO hw:3,0 pisound-micro PSM-1234567
...
If you don't see the Pisound Micro listed by any of the above utilities, feel free to ask for assistance on our community forums.
Using Pisound Micro#
Device Id#
In audio software, you can use an identifier such as hw:3,0 (3rd card, 0 port), as shown in above section's example output, when configuring audio devices in your audio software. However, as this may differ based on your system configuration or even whether there's some additional USB devices connected, a better value to use is the hw:pisoundmicro identifier which should consistently identify the Pisound Micro. For specifying the MIDI ports for MIDI software, you may use pisoundmicro:0.
ALSA and Mixer Controls#
Pisound Micro has numerous mixer controls for managing input/output volumes and configuring the on-board audio codec. Here's a quick overview:
# Open the graphical mixer interface (press F6 to select pisoundmicro)
alsamixer
# Reset to default settings if needed
alsactl init pisoundmicro
(The pisound-micro APT package must be installed as detailed in above section)
For detailed instructions on using ALSA tools (alsamixer, amixer, and alsactl) with Pisound Micro, including essential commands and configuration examples, see ALSA Mixer.