Board Tour and Pinout
The connectors, components and header pins of the Neuro N6, with the microcontroller pin and the datasheet net name behind each.
The Neuro N6 follows the Adafruit Feather outline at 53.04 by 22.83 mm. The USB-C connector and the battery connector are at one end, the two board-to-board connectors on the underside, and the header pins run along the long edges. Pin and net names in this page follow the Neuro N6 datasheet and the Rev C schematic.
Components
| Component | Part | Function |
|---|---|---|
| Microcontroller | STM32N657I0HXQ, VFBGA178, 12 x 12 mm, 0.8 mm pitch, 106 I/Os | Cortex-M55 at 800 MHz and Neural-ART accelerator at 1 GHz |
| PSRAM | AP Memory APS51208N, 64 MB, OctoSPI | Working memory for frames, models and sketch buffers |
| Flash | Macronix MX25UM25645G, 32 MB, OctoSPI | Bootloader, application, model weights, WiFi firmware, assets |
| USB | USB-C receptacle, high speed | Power, serial console, video stream, DFU upload |
| Board-to-board connectors | 40-pin HC-PBB40C-40DP-0.4V-02 and 30-pin HC-PBB40C-30DP-0.4V-02 | To the Neuro Vision expansion modules |
| Inertial unit | ST LSM6DSL | Three-axis accelerometer, three-axis gyroscope, temperature |
| Magnetometer | MEMSIC MMC5603NJ | Three-axis field, plus or minus 30 gauss, 0.0625 mG resolution |
| Microphone | ST MP34DT05-A | Omnidirectional PDM digital microphone |
| RGB LED | XL-B1212RGBA-HF, common anode | Red PE11, green PD6, blue PC1. Pulses red in bootloader mode |
| Charging status LED | Red, 16-213/R6C | Charging, or flashing when USB is connected without a battery. Not programmable |
| USER button | Momentary, external pull-down | PG8 |
| Reset button | Momentary | Resets the MCU and peripherals. Two presses within 900 ms enter the bootloader |
| Charger | TP4054, linear, 500 mA | Single cell lithium ion or polymer, from USB |
| Power path | Two DZDH0401 ideal diode controllers with PMPB15XP MOSFETs | Selects between USB and battery |
| Regulators | Two AP3441 buck converters for 3.3 V and 1.8 V; ETA5055 LDOs for the analogue 1.8 V, always-on 1.8 V and 3.3 V domains | |
| Oscillators | 48 MHz oscillator, 32.768 kHz crystal | HSE and LSE |
| USB protection | USBLC6-2P6 on the data lines, ESD diodes on the I2C header | |
| Battery connector | JST S2B-PH-SM4-TB, mates with PHR-2 | Single cell |
| Debug connector | M0800RS-06-GN, six pin, mates with M0800HI-06-GN | SWDIO, SWCLK, NRST and the BOOT0 and BOOT1 pins |
Header pins
The header follows the Adafruit Feather pinout. The pins carry the functions below.
| Name | MCU port pin | Datasheet ball | Function |
|---|---|---|---|
RX (D0) | PD0 | A12 | UART4 receive |
TX (D1) | PD1 | B12 | UART4 transmit |
D5 | PE9 | B14 | Digital, PWM capable |
D6 | PF5 | J4 | Digital |
D9 | PD12 | E11 | Digital. Interrupt line shared with A2 |
D10 | PF10 | J3 | Digital, PWM capable. Default chip select |
D11 | PF15 | K3 | Digital |
D12 | PA3 | K11 | Digital, PWM capable |
D13 | PG14 | L5 | Digital, PWM capable |
A0 | PF13 | M2 | Analogue input with ADC |
A1 | PF11 | L2 | Analogue input with ADC |
A2 | PF12 | L3 | Analogue input with ADC. Interrupt line shared with D9 |
A3 | PF3 | J5 | Analogue input with ADC |
A4 | PF14 | K2 | Analogue input with ADC |
A5 | PG15 | M5 | Analogue input with ADC |
SDA | PD15 | A10 | I2C data, 3.3 V, 4.7k pull-up |
SCL | PD14 | C8 | I2C clock |
MOSI | PD7 | B11 | SPI2 |
MISO | PD11 | F11 | SPI2 |
SCK | PF2 | K1 | SPI2 |
Power pins
The header follows the Adafruit Feather specification. The 16-pin side runs RST, 3.3V, AREF, GND, A0 to A5, SCK, MOSI, MISO, RX, TX; the 12-pin side runs BAT, EN, USB, D13, D12, D11, D10, D9, D6, D5, SCL, SDA. The power pins carry the functions the specification assigns them.
| Header pin | Net | Function |
|---|---|---|
USB | VBUS | 5 V from the USB-C port when connected. A 4.5 to 5.5 V supply applied here powers the board and the charger |
BAT | VBAT | Battery, in parallel with the JST-PH connector |
3.3V | VDD3V3 | Regulated 3.3 V output |
AREF | VREF | Analogue 1.8 V reference output, 100 mA |
EN | REGEN | Regulator enable input. Pulled low to disable the 3.3 V rail |
RST | NRST | Reset, active low |
GND | GND | Ground |
VIN, the 5 V rail after the ideal diode, is routed to the board-to-board connectors for the expansion modules.
The board datasheet lists D5, D10, D12 and D13 as PWM capable pins. The Arduino core currently implements analogWrite on D5, A4 and the LED channels; see Digital and Analog Pins. D2, D3, D4, D7 and D8 are not routed. Digital pins are 3.3 V. The board datasheet rates them at 4 mA per pin; the STM32N6 I/Os themselves can sink or source up to 20 mA depending on the speed setting, so the board figure is the one to design to. Analogue inputs are referenced to 1.8 V and are converted by the STM32N6's two 12-bit ADCs, which run at up to 5 Msps.
Board-to-board connectors
The 40-pin and 30-pin connectors carry the interfaces to the expansion modules. Minimum mating height is 3.5 mm, which leaves clearance for headers soldered to the Neuro N6.
| Interface | Connector | Signals | Used by |
|---|---|---|---|
| MIPI CSI-2 | 40-pin | Clock lane and two data lanes, D-PHY version 1.2, CSI-2 version 1.3, up to 2.5 Gbit/s per lane | Camera on every module |
| I2C2 | 40-pin | SCL D12, SDA C12. The STM32N6 I2C is Fast-mode Plus capable | Camera control, module sensors |
| SDMMC | 40-pin | Four data lines, clock, command, up to 200 MHz. SD 6.0, SDIO 4.0 and eMMC 5.1 | Wireless module on the -W carriers, or an SD card |
| SPI1 | 40-pin | Shares connector pins with LTDC display signals | Thermal module video, on pins the TFT carriers use for the display |
| USART6 | 30-pin | RX, TX, RTS, CTS | Bluetooth LE HCI on the -W carriers |
| SAI1 block B | 30-pin | MCLK, SCK, FS, SD | Speaker amplifier on the TFT carriers, or a microphone |
| LTDC | 40-pin and 30-pin | RGB565, 16-bit, up to XGA. The controller blends two layers | Display on the TFT carriers |
| Power | Both | 3V3, 1V8, VIN |
For the full connector pinout the datasheet refers to the Neuro N6 schematic.
I2C buses
The board has two I2C interfaces. One is on the Feather header SDA and SCL pins. The other is on the 40-pin connector and reaches the camera module and its sensors. Both have on-board pull-up resistors, and the on-board inertial unit and magnetometer share the bus with the module sensors. The Arduino core's Wire object drives the bus the camera and sensors share; see I2C with Wire.
Mechanical
53.04 by 22.83 by 8.85 mm, 6.7 g, with mounting holes at the Feather positions. A 3D printed case is available; see 3D Printed Case.
Schematic
The Rev C schematic, part number OL-DEV-N6-001, is published in the Neuro-N6-Hardware repository under the CERN-OHL-S v2 licence in four sheets: STM32N6 and memories, camera and connectors, power, and sensors. See Downloads.