This ESP32-C6 based module provides the board with access to Wifi, BLE and IEEE802.15.4 (mesh network) connectivity while also controlling the LoRa radio module.
Camera connector
The camera connector is used to connect a CSI camera mdoule. It is pinout-compatible with the camera connector on the Raspberry Pi Zero and 5. Note that software support is limited to a subset of Raspberry Pi compatile camera module sensor chips such as OV5647.
QWIIC & Stemma QT compatible I2C & I3C connector
This connector can be used to connect external I2C or I3C based accessories. Both Adafruit and Sparkfun make a variety of modules and cables which could be connected to this port.
USB-C device port
This port is used to charge the battery, to program and debug the ESpP32-P4 and ESp32-C6 microcontrollers and to install apps and browse files from your computer.
USB-A host port
This port can be used to connect an USB device to the Tanmatsu.
SD card slot
Accepts micro SD memory cards including modern high speed SDIO 3.0 cards.
Battery connector
Allows for connecting a single cell Lithium Polymer or Lithium Ion battery cell. Using a protected cell is mandatory. Unprotected cells could potentially be drained below their lowest allowable voltage, which causes damage to the battery. Current control, over voltage protection and propper constant voltage/current charge control are is built-in into the Tanmatsu mainboard.
Sensor connector
Can be used to connect an I2C connected sensor PCB.
1 - Tanmatsu: specifications
This section lists the technical specifications of the Tanmatsu hardware.
Note: information on this page is actively being worked on and might contain accidental errors and inaccuracies.
Physical dimensions
Size of the device including the 3D printed case:
Width: 12 cm (4.72 in)
Length: 13.5 cm (5.31 in)
Height: 1.8 cm (0.71 in)
Weight: 215 g (0.47 pounds) including case and battery
Note: display supports 16M colors (24-bit / RGB888) but current software can not make use of this mode.
Nicolai Electronics developed an ESP-IDF component for configuring the MIPI DSI peripheral in the ESP32-P4 for use with this display. The component also allows for easy switching between the display on the Tanmatsu and the display included with the official ESP32-P4 development kit.
The display will be available as a spare part from our webshop once Tanmatsu is shipped.
Keyboard
Full 69-key alphanumeric keyboard with colored 6 function keys
Metal dome sheet for tactile feeling
LED backlight (white)
The keyboard has been developed by our awesome friends at Solder Party.
The keyboard and corresponding metal dome sheet will be available as a spare part in our webshop once Tanmatsu is shipped.
Battery
Single cell protected Lithium Polymer battery with PH-2.0 style connector. The connector and pinout are compatible with the battery connector on Adafruit boards.
Capacity: tbd (at least 2000 mAh)
Connector: PH-2.0
Chemnistry: Lithium polymer
Single cell 3.7 volt
The battery will be available as a spare part in our webshop once Tanmatsu is shipped.
Connectors and interfaces
On the outside of the case:
USB-C device port connected to an USB hub. Allows access to:
The ESP32-P4 USB interface (PHY 1, defaults to USB-serial/JTAG debug interface but can be remapped to custom USB functions by software)
ESP32-C6 USB-serial/JTAG debug interface
Personality module expansion port (provides access to an optionally connected USB device on a personality module)
USB-A host port (480 Mbit superspeed USB 2.0), provides 1A of current with automatic current limiting
Qwiic and Stemma-QT compatible 4-pin SH connector for connecting I2C and I3C accessories
3.5 mm headphone jack
CATT (Connect All The Things) connector: combined PMOD and SAO compatible 2.54 mm pinsocket optionally also usable as JTAG interface for debugging the ESP32-P4 application processor
Three push buttons (Power, up and down). Holding down the down button when applying power puts the ESP32-P4 into USB download mode for easy firmware recovery
Micro SD card slot compatible with SDIO 2 and SDIO 3 cards at 3.3v and 1.8v voltage levels
(optional) SMA antenna connector for LoRa antenna
On the inside of the case:
PH-2.0 2-pin battery connector
PicoBlade 2-pin speaker connector for 8 Ohm speaker
Raspberry Pi camera compatible 22-pin MIPI CSI camera interface
IPEX-1 antenna connector for LoRa antenna
Personality module connector: 36-pin 2.54 mm pinsocket with:
Access to power rails (5V, Vbatt, Vsys and 3.3v)
USB hub downstream port connected to the USB-C port via an USB hub
Internal I2C bus (can be used for sensors and for an identification EEPROM)
14 GPIO pins
ESP32-P4 USB interface (PHY 2) or 2 extra GPIO pins
UART interface or 2 extra GPIO pins
I2S interface or 4 extra GPIO pins (shared with audio codec, when used as GPIO audio functionality is unavailable)
I3C bus (shared with 4-pin SH connector) or 2 extra GPIO pins
Chips and modules
WiFi, BLE and IEEE 802.15.4 radio
Module: Espressif Systems ESP32-C6-WROOM-1-N8
CPU: 32-bit RISC-V single core microprocessor, up to 160 MHz
The management coprocessor is responsible for reading the keyboard matrix and power management. It presents itself as an I2C peripheral on the internal I2C bus of the Tanmatsu and provides the following services:
Keyboard events
PWM control for the display backlight
PWM control for the keyboard backlight
Real Time Clock (RTC) backed by watch crystal
Alarm wakeup
PMIC control
Power switching for USB-A port
Power and boot-mode control for the ESP32-C6 radio module
Power switching for audio amplifier
Headphone detection
Addressable LED control for the 6 built-in addressable LEDs
The firmware for this chip will be made available under terms of the MIT license after the Tanmatsu becomes available in April 2025. Modifying the firmware is possible but is not recommended.
The firmware of the coprocessor can be updated from the ESP32-P4 application processor, for this Nicolai Electronics developed an ESP-IDF component capable of reprogramming CH32V20x and CH32V30x microcontrollers from the ESP32-P4 application processor.
LoRa radio
The PCB footprint supports a range of radio modules from Ai-Thinker. Software support will initially be provided for the RA-01SH 868 MHz band SX1262 based and the RA-01S 433 MHz band SX1268 based modules.
All Tanmatsu boards will be delivered with a module which has the IPEX-1 antenna connector installed. Optionally an SMA antenna connector can be installed to allow connecting standard external LoRa antennas. Tanmatsu will be provided with either an internal IPEX-1 antenna or a basic SMA antenna depending on the option chosen.
Audio
Everest Semiconductor ES8156 audio codec:
Hardware volume control via I2C interface
Stereo audio DAC
FM8002A mono speaker amplifier:
Can be switched on and off using the coprocessor
Connected to built-in 8 Ohm speaker
Power management
PMIC
Texas Instruments BQ25895RTW PMIC for battery charging and monitoring as well as DC/DC boost converter for 5 volt rail (to power USB-A port, addressable LEDs and 5 volt pin on the personality module expansion header).
Provides soft power on/off functionality when the device is battery powered and allows seamless transition between battery and USB-C power source.
3.3v rail DC/DC converter
Texas Instruments TPS63020DSJR DC/DC buck and boost converter providing a stable 3.3v rail even when the battery voltage drops below 3.3 volt.
Backlight drivers
Two AP3032KTR backlight driver chips, one for the display and one for the keyboard backlight LEDs. Brightness controlled using PWM via the CH32V203 coprocessor.
Standby power rail
A small LDO provides 2.5v to the Vbatt rail of the CH32V203 coprocessor even when the device is off. This uses almost no power (theoretically the battery would last over 10 years on a single charge if the device is never turned on, ignoring LiPo battery self-discharge) and allows the Real Time Clock in the CH32V203 coprocessor to keep track of time even when the device is off. A special latch circuit circuit allows the CH32V203 to power on the Tanmatsu using its alarm pulse output by emulating a press of the power button.
Addressable LEDs
Six SK6805-EC20 addressable LEDs controlled by the coprocessor.
Sensors
Bosch BMI270 IMU combined accelerometer and gyroscope
Header for optional SCD40 or SCD41 CO2, temperature and humidity sensor (not populated, modules are available on AliExpress) or other I2C controlled sensor
Questions?
If you have questions please contact us by joining one of our community chatgroups (Telegram and Discord) or by emailing us.
2 - Tanmatsu: 3D printed case
Information about the 3D printed case for Tanmatsu.
Note: information on this page is actively being worked on and might contain accidental errors and inaccuracies.
Filament
The 3D printed case and spacer are printed using Extrudr PLA NX2 on Prusa Mini and Prusa XL printers.
Design files
Once Tanmatsu is available the spacer and case designs will be published as STEP and STL files.
The 3D printed case and spacer will both be available as a spare part from our webshop once Tanmatsu is shipped.
Photos
These photos show some of the prototype 3D printed cases, final design will differ slightly because we are still actively working on improving the design for easier manufacturing and better dust protection.
Special thanks
We want to thank our friends over at YTec 3D for developing the Tanmatsu case and designs. Check out their amazing projects.
Questions?
If you have questions please contact us by joining one of our community chatgroups (Telegram and Discord) or by emailing us.
