Power

• Do not attempt to power the board using the 3V3 output pin. This pin is intended for powering 3.3V peripherals (generally around 400mA max) using Sonatino's onboard regulator. Connecting a power source to this pin may damage the board.
• If you power Sonatino using the VIN pin, DO NOT connect a battery or USB-C to the board. Charging only works with USB-C, and VIN should never be used with another power source connected at the same time.
• Sonatino can draw significant current at times (depending on usage; can be 1A or more). If your power source cannot supply enough current, you may experience unexpected behavior.
• The charging circuit is configured to deliver up to 500mA of current to a battery. Please check that your battery can handle this charging rate, especially for batteries with less than 500mAh of capacity.
• A few ways to reduce power consumption and extend battery life:
  
  • Turn off wireless functions on the ESP32-S3 when not in use.
  • Configure the ESP32-S3 to use a lower CPU frequency or dynamic frequency scaling (DFS).
  • Set GPIO 46 to LOW: this shuts down the 2.5W amp, headphone amp, and microphone preamp.
  • Set GPIO 14 to LOW to mute the DAC.
  • Stop outputting a MCLK signal on the ESP32-S3's GPIO 0 (may require calling i2s_stop()). This will power down the ADC and DAC.
  • Put the ESP32-S3 into light sleep or deep sleep (esp_light_sleep_start() or esp_deep_sleep_start()). If you've shut down the amps by setting GPIO 46 to LOW, don't forget to call gpio_deep_sleep_hold_en() before sleeping to keep the pin held low.
  • Remove any microSD card if you aren't using it.
  • You can disable the green power LED by carefully cutting the trace between the two jumper pads of JP1 on the underside of the board.

Programming

• Sonatino can be programmed using a number of different software tools. While Arduino IDE is probably the easiest for getting started, PlatformIO and ESP-IDF offer some additional benefits for more advanced projects.
• When uploading code, Arduino IDE will usually take care of putting the board into flashing mode and then resetting the board when the upload is complete. If that doesn't work, check that the correct port and board is selected, then try again. Some development tools don't handle the flashing process correctly by default, so you may need to adjust your software's board settings.
• In rare cases, you may need to manually put the board into flashing mode. This can be done two different ways, depending on your board revision (found on the underside of the board, near the right-hand edge — looks like "rev x.x.x"):
  
  • Rev 2.6.1 and above: Hold down the "BOOT" button, and while holding it down press and release the "RST" button. Then release the "BOOT" button.
  • Rev 2.5.x: Temporarily short (e.g., with a short length of wire) the "MCLK/0" pad on the underside of the board with GND. While doing that, press and release the reset button ("RST") on the front and remove the wire.

Audio

• Sonatino uses separate bit clock (BCLK) and word clock (LRCLK) lines for the DAC and ADC — as noted in the pinout. The ESP32-S3 supports two I²S ports, so you can configure and use the DAC and ADC simultaneously (technically they could share those lines, but Sonatino wires them separately for added flexibility).
• GPIO 18 and GPIO 21 are connected to FSAMPEN and IWL pins of the WM8782 (ADC), respectively. These pins are used to configure the ADC's sample rate and word length. See the WM8782 datasheet for more information.
• GPIO 47 and GPIO 48 are connected to GAIN0 and GAIN1 of the TPA6132A2 (Headphone Amp), respectively. The default state corresponds to 0 dB gain (GAIN0 is pulled HIGH and GAIN1 is pulled LOW), but can be set to -6 dB, 0dB, 3dB, or 6 dB based on pin state. See section 7.4.1 of the TPA6132A2 datasheet for more information.
• The 2.5W mono amplifier is connected to the left output channel.
• Without properly setting volume/gain (in software and hardware), audio output from Sonatino can be very loud! It can also become distorted if the volume is set too high. Please protect your ears and be careful when testing audio output!
• Crackling, stuttering, or choppy audio is most often caused by misconfigured settings (sample rate, word length, master clock, DMA buffer, etc.) or by delays in the audio processing pipeline. Double-check that all your settings are correct and that no time-consuming tasks are blocking the delivery of audio samples. You may need to use RTOS programming to take advantage of both cores of the ESP32-S3.

Cases / Enclosures

• Sonatino will fit into some cases designed for the Raspberry Pi Zero, but not all. Cases that are open around the edges of the board generally work without modification, but those with cutouts for ports on the Raspberry Pi Zero (including the official case sold by Raspberry Pi) won't match the ports on Sonatino. Often, those cases can be modified by expanding or cutting out new holes for Sonatino's ports.

Microcontroller & Storage

• Microcontroller: ESP32-S3-WROOM-1 with 16 MB flash and 8 MB PSRAM (previously 2 MB PSRAM)
• Additional Storage: microSD card slot with SPI interface

Audio

• DAC: Cirrus Logic WM8524 — up to 24-bit 192kHz output (stereo)
• ADC: Cirrus Logic WM8782 — up to 24-bit 192kHz input (mono)
• Audio format: I²S
• Speaker Amp: PAM8302 — 2.5W @ 4Ω (mono) with adjustable volume
• Interface: 3.5mm audio jack supporting input and output (TRRS, CTIA standard)
• Stereo Headphone Amp: TPA6132A2
• Microphone Preamp: MAX4467
• Input Level: Mic or line level
• Output Level: Line or headphone level
• Speaker Connection: onboard pins, optional screw terminal

Connectivity

• WiFi: 802.11 b/g/n
• Bluetooth: 5.0 (LE)
• GPIO: 13 general-purpose I/O pins
• USB-C for programming and data I/O

Power

• Power Source: USB-C, 3.7V LiPo/Li-Ion battery, or 5V DC
• Battery Charging: Charging circuit with overcharge and over-discharge protection
• Low-Power Mode: ESP32-S3 supports deep sleep, and audio components can be put into low-power mode to extend battery life
• Battery Connection: onboard pins, optional JST PH 2 battery connector (check polarity before connecting)

Status and Control

• Trim pots for adjusting speaker volume and mic gain
• Dip switches for selecting mic/line level and line/headphone level
• Reset button
• User-programmable blue status LED
• Power and battery charging status LEDs

Physical

• Dimensions: 65 x 30 mm x 7mm (2.6 x 1.2 x 0.3 in)
• Weight: 11 g (0.4 oz)
• Same size as a Raspberry Pi Zero (not compatible with Pi Zero)
• Can be used with some Pi Zero cases (may require case modification)