ItsyBitsy nRF52840
Overview
The Adafruit ItsyBitsy nRF52840 Express is a small (36 mm x 18 mm) ARM development board with an onboard RGB LED, USB port, 2 MB of QSPI flash, and range of I/O broken out onto 21 GPIO pins.
This development kit has the following features:
ADC
CLOCK
FLASH
GPIO
I2C
I2S
MPU
NVIC
PWM
QSPI
RADIO (Bluetooth Low Energy and 802.15.4)
RTC
SPI
UARTE
USB
WDT
Hardware
nRF52840 ARM Cortex-M4F CPU at 64MHz
1 MB of flash memory and 256 KB of SRAM
2 MB of QSPI flash
A user LED
A user switch
An RGB DotStar LED
Native USB port
One reset button
Supported Features
The adafruit_itsybitsy board supports the hardware features listed below.
- on-chip / on-board
- Feature integrated in the SoC / present on the board.
- 2 / 2
-
Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files. -
vnd,foo -
Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.
Type |
Location |
Description |
Compatible |
|---|---|---|---|
CPU |
on-chip |
ARM Cortex-M4F CPU1 |
|
ADC |
on-chip |
Nordic Semiconductor nRF family SAADC node1 |
|
ARM architecture |
on-chip |
Nordic UICR (User Information Configuration Registers)1 |
|
on-chip |
Nordic EGU (Event Generator Unit)6 |
||
on-chip |
Nordic nRF family ACL (Access Control List)1 |
||
on-chip |
Nordic nRF family MWU (Memory Watch Unit)1 |
||
Audio |
on-chip |
Nordic PDM (Pulse Density Modulation interface)1 |
|
Clock control |
on-chip |
Nordic nRF clock control node1 |
|
Comparator |
on-chip |
Nordic nRF COMP (analog COMParator)1 |
|
Counter |
on-chip |
Nordic nRF timer node5 |
|
Cryptographic accelerator |
on-chip |
Nordic ECB (AES electronic codebook mode encryption)1 |
|
on-chip |
Nordic nRF family CCM (AES CCM mode encryption)1 |
||
on-chip |
ARM TrustZone CryptoCell 3101 |
||
Debug |
on-chip |
ARMv7 instrumentation trace macrocell1 |
|
Flash controller |
on-chip |
Nordic NVMC (Non-Volatile Memory Controller)1 |
|
on-chip |
Properties defining the interface for the Nordic QSPI peripheral1 |
||
GPIO & Headers |
on-chip |
NRF5 GPIOTE1 |
|
on-chip |
NRF5 GPIO2 |
||
I2C |
on-chip |
Nordic nRF family TWI (TWI master)1 |
|
on-chip |
Nordic nRF family TWIM (TWI master with EasyDMA)1 |
||
I2S |
on-chip |
Nordic I2S (Inter-IC sound interface)1 |
|
IEEE 802.15.4 |
on-chip |
Nordic nRF IEEE 802.15.4 node1 |
|
Input |
on-board |
Group of GPIO-bound input keys1 |
|
Interrupt controller |
on-chip |
ARMv7-M NVIC (Nested Vectored Interrupt Controller)1 |
|
LED |
on-board |
Group of GPIO-controlled LEDs1 |
|
LED strip |
on-board |
APA102 SPI LED strip1 |
|
Miscellaneous |
on-chip |
Nordic FICR (Factory Information Configuration Registers)1 |
|
on-chip |
Nordic nRF family PPI (Programmable Peripheral Interconnect)1 |
||
MTD |
on-chip |
Flash node1 |
|
on-chip |
Fixed partitions of a flash (or other non-volatile storage) memory2 |
||
on-board |
QSPI NOR flash supporting the JEDEC CFI interface1 |
||
Networking |
on-chip |
Nordic nRF family RADIO peripheral1 |
|
on-chip |
Nordic nRF family NFCT (Near Field Communication Tag)1 |
||
Pin control |
on-chip |
The nRF pin controller is a singleton node responsible for controlling pin function selection and pin properties1 |
|
Power management |
on-chip |
Nordic nRF power control node1 |
|
PWM |
on-chip |
nRF PWM4 |
|
on-chip |
nRFx S/W PWM1 |
||
Regulator |
on-chip |
Nordic nRF5X regulator (fixed stage of the core supply)1 |
|
on-chip |
Nordic nRF52X regulator (high voltage stage of the main supply)1 |
||
Retained memory |
on-chip |
Nordic GPREGRET (General Purpose Register Retention) device2 |
|
RNG |
on-chip |
Nordic nRF family RNG (Random Number Generator)1 |
|
RTC |
on-chip |
Nordic nRF RTC (Real-Time Counter)3 |
|
Sensors |
on-chip |
Nordic nRF family TEMP node1 |
|
on-chip |
Nordic nRF quadrature decoder (QDEC) node1 |
||
Serial controller |
on-chip |
Nordic nRF family UARTE (UART with EasyDMA)2 |
|
SPI |
on-chip |
Nordic nRF family SPIM (SPI master with EasyDMA)2 |
|
on-chip |
Nordic nRF family SPI (SPI master)2 |
||
SRAM |
on-chip |
Generic on-chip SRAM description1 |
|
Timer |
on-chip |
ARMv7-M System Tick1 |
|
USB |
on-chip |
Nordic nRF52 USB device controller1 |
|
Watchdog |
on-chip |
Nordic nRF family WDT (Watchdog Timer)1 |
Connections and IOs
The Adafruit ItsyBitsy nRF52840 Express Learn site [1] has detailed information about the board including pinouts [2] and the schematic [3].
LED
LED0 (red) = P0.06
LED1 (Adafruit DotStar)
DATA = P0.08
CLK = P1.09
Logging
Logging is done using the USB-CDC port. See the Logging sample or the Console over USB CDC ACM sample applications to see how this works.
Programming and Debugging
The ItsyBitsy ships with the BOSSA compatible UF2 bootloader. The bootloader can be entered by quickly tapping the reset button twice.
First time setup
Some versions of this board were shipped with a buggy bootloader. Ensure that the bootloader is up to date by following the Adafruit UF2 Bootloader update [4] tutorial. Note that this tutorial was made for the Adafruit Feather nRF52840, but the steps to update the bootloader are the same for the ItsyBitsy. The files for the ItsyBitsy bootloader can be found in the Adafruit nRF52 Bootloader repo [5].
The building and flashing of Zephyr applications have been tested with release 0.7.0 of the UF2 bootloader.
Flashing
Flashing is done by dragging and dropping the built Zephyr UF2-file
into the ITSY840BOOT drive.
Build the Zephyr kernel and the Blinky sample application:
west build -b adafruit_itsybitsy/nrf52840 samples/basic/blinky
Connect the ItsyBitsy to your host computer using USB
Tap the reset button twice quickly to enter bootloader mode
Flash the image:
Drag and drop the file
samples/basic/blinky/build/zephyr/zephyr.uf2intoITSY840BOOT
The device will disconnect and you should see the red LED blink.