96Boards Neonkey

Overview

96Boards Neonkey board is based on the STMicroelectronics STM32F411CE Cortex M4 CPU.

96Boards Neonkey

96Boards Neonkey

This board acts as a sensor hub platform for all 96Boards compliant family products. It can also be used as a standalone board.

Hardware

96Boards Neonkey provides the following hardware components:

  • STM32F411CE in UFQFPN48 package

  • ARM® 32-bit Cortex®-M4 CPU with FPU

  • 84 MHz max CPU frequency

  • 1.8V work voltage

  • 512 KB Flash

  • 128 KB SRAM

  • On board sensors:

    • Temperature/Humidity: SI7034-A10

    • Pressure: BMP280

    • ALS/Proximity: RPR-0521RS

    • Geomagnetic: BMM150

    • Accelerometer/Gyroscope: BMI160

    • AMR Hall sensor: MRMS501A

    • Microphone: SPK0415HM4H-B

  • 4 User LEDs

  • 15 General purpose LEDs

  • GPIO with external interrupt capability

  • I2C (3)

  • SPI (1)

  • I2S (1)

Supported Features

The Zephyr 96b_neonkey board configuration supports the following hardware features:

Interface

Controller

Driver/Component

NVIC

on-chip

nested vector interrupt controller

SYSTICK

on-chip

system clock

UART

on-chip

serial port

GPIO

on-chip

gpio

PINMUX

on-chip

pinmux

FLASH

on-chip

flash

SPI

on-chip

spi

I2C

on-chip

i2c

More details about the board can be found at 96Boards website [1].

The default board configuration can be found in boards/96boards/neonkey/96b_neonkey_defconfig

Connections and IOs

LED

  • LED1 / User1 LED = PB12

  • LED2 / User2 LED = PB13

  • LED3 / User3 LED = PB14

  • LED4 / User4 LED = PB15

Push buttons

  • BUTTON = RST (SW1)

  • BUTTON = USR (SW2)

System Clock

96Boards Neonkey can be driven by an internal oscillator as well as the main PLL clock. By default System clock is sourced by PLL clock at 84MHz, driven by internal oscillator.

Serial Port

On 96Boards Neonkey Zephyr console output is assigned to USART1. Default settings are 115200 8N1.

I2C

96Boards Neonkey board has up to 3 I2Cs. The default I2C mapping for Zephyr is:

  • I2C1_SCL : PB6

  • I2C1_SDA : PB7

  • I2C2_SCL : PB10

  • I2C2_SDA : PB3

  • I2C3_SCL : PA8

  • I2C3_SCL : PB4

SPI

96Boards Neonkey board has one SPI. The default SPI mapping for Zephyr is:

  • SPI1_NSS : PA4

  • SPI1_SCK : PA5

  • SPI1_MISO : PA6

  • SPI1_MOSI : PA7

Programming and Debugging

Building

Here is an example for building the Hello World application.

# From the root of the zephyr repository
west build -b 96b_neonkey samples/hello_world

Flashing

96Boards Neonkey can be flashed by two methods, one using the ROM bootloader and another using the SWD debug port (which requires additional hardware).

Using ROM bootloader:

ROM bootloader can be triggered by the following pattern:

  1. Connect BOOT0 to VDD (link JTAG pins 1 and 5 on P4 header)

  2. Press and hold the USR button

  3. Press and release the RST button

More detailed information on activating the ROM bootloader can be found in Chapter 29 of Application note AN2606 [2]. The ROM bootloader supports flashing via UART, I2C and SPI protocols.

For flashing, stm32flash [3] command line utility can be used. The following command will flash the zephyr.bin binary to the Neonkey board using UART and starts its execution:

$ stm32flash -w zephyr.bin -v -g 0x08000000 /dev/ttyS0

Note

The above command assumes that Neonkey board is connected to serial port /dev/ttyS0.

Using SWD debugger:

For flashing via SWD debug port, 0.1” male header must be soldered at P4 header available at the bottom of the board, near RST button.

Use the Black Magic Debug Probe [4] as an SWD programmer, which can be connected to the P4 header using its flying leads and its 20 Pin JTAG Adapter Board Kit. When plugged into your host PC, the Black Magic Debug Probe enumerates as a USB serial device as documented on its Getting started page [5].

It also uses the GDB binary provided with the Zephyr SDK, arm-zephyr-eabi-gdb. Other GDB binaries, such as the GDB from GCC ARM Embedded, can be used as well.

$ arm-zephyr-eabi-gdb -q zephyr.elf
(gdb) target extended-remote /dev/ttyACM0
Remote debugging using /dev/ttyACM0
(gdb) monitor swdp_scan
Target voltage: 1.8V
Available Targets:
No. Att Driver
 1      STM32F4xx
(gdb) attach 1
Attaching to Remote target
0x080005d0 in ?? ()
(gdb) load

Debugging

After flashing 96Boards Neonkey, it can be debugged using the same GDB instance. To reattach, just follow the same steps above, till “attach 1”. You can then debug as usual with GDB. In particular, type “run” at the GDB prompt to restart the program you’ve flashed.

References