Adafruit Feather nRF52840 Express

Runs real compiled Adafruit Feather nRF52840 Express firmware on an in-browser Nordic nRF52840 (ARM Cortex-M4F, 64 MHz). The default "NeoPixel Rainbow" is a bare-metal C program that cycles a smooth rainbow on the single on-board WS2812 NeoPixel (P0.16), blinks the red user LED (P1.15) as a heartbeat, and announces each colour over the UARTE0 serial console — so the board lights AND prints out of the box. The NeoPixel colour is REAL: the program bit-bangs the 800 kHz WS2812 one-wire protocol on P0.16 and the board decodes the HIGH-pulse widths into a live RGB value (a long LOW latches the frame). "Blink" alternates the red (P1.15) and blue CONN (P1.10) LEDs with the nRF52 GPIO OUTSET/OUTCLR registers. "UART Hello + Counter" brings up UARTE0 (TX on P0.25) and prints a greeting and an incrementing four-digit counter to the serial console using a real EasyDMA transfer, blinking the LED each line. "Button" reads the on-board USER switch (SW1, P1.02, active-low): press it (the SW1 button in the shared Controller panel) to turn the NeoPixel green and light the blue LED, release for dim red and the red LED — each edge prints over the console. Open the debugger, or add ?debug, to single-STEP real Thumb instructions from flash at 0x00000000, set PC breakpoints and write watchpoints, and read the ARM registers (r0-r15, xPSR, N/Z/C/V) and the real nRF52840 memory map live (FLASH 0, RAM 0x20000000, APB 0x40000000, GPIO 0x50000000). A bare Feather has no on-board speaker, so it is honestly silent.

Runs real compiled Adafruit Feather nRF52840 Express firmware on an in-browser Nordic nRF52840 (ARM Cortex-M4F, 64 MHz). The default "NeoPixel Rainbow" is a bare-metal C program that cycles a smooth rainbow on the single on-board WS2812 NeoPixel (P0.16), blinks the red user LED (P1.15) as a heartbeat, and announces each colour over the UARTE0 serial console — so the board lights AND prints out of the box. The NeoPixel colour is REAL: the program bit-bangs the 800 kHz WS2812 one-wire protocol on P0.16 and the board decodes the HIGH-pulse widths into a live RGB value (a long LOW latches the frame). "Blink" alternates the red (P1.15) and blue CONN (P1.10) LEDs with the nRF52 GPIO OUTSET/OUTCLR registers. "UART Hello + Counter" brings up UARTE0 (TX on P0.25) and prints a greeting and an incrementing four-digit counter to the serial console using a real EasyDMA transfer, blinking the LED each line. "Button" reads the on-board USER switch (SW1, P1.02, active-low): press it (the SW1 button in the shared Controller panel) to turn the NeoPixel green and light the blue LED, release for dim red and the red LED — each edge prints over the console. Open the debugger, or add ?debug, to single-STEP real Thumb instructions from flash at 0x00000000, set PC breakpoints and write watchpoints, and read the ARM registers (r0-r15, xPSR, N/Z/C/V) and the real nRF52840 memory map live (FLASH 0, RAM 0x20000000, APB 0x40000000, GPIO 0x50000000). A bare Feather has no on-board speaker, so it is honestly silent.

Runs real compiled Adafruit Feather nRF52840 Express firmware on an in-browser Nordic nRF52840 (ARM Cortex-M4F, 64 MHz). The default "NeoPixel Rainbow" is a bare-metal C program that cycles a smooth rainbow on the single on-board WS2812 NeoPixel (P0.16), blinks the red user LED (P1.15) as a heartbeat, and announces each colour over the UARTE0 serial console — so the board lights AND prints out of the box. The NeoPixel colour is REAL: the program bit-bangs the 800 kHz WS2812 one-wire protocol on P0.16 and the board decodes the HIGH-pulse widths into a live RGB value (a long LOW latches the frame). "Blink" alternates the red (P1.15) and blue CONN (P1.10) LEDs with the nRF52 GPIO OUTSET/OUTCLR registers. "UART Hello + Counter" brings up UARTE0 (TX on P0.25) and prints a greeting and an incrementing four-digit counter to the serial console using a real EasyDMA transfer, blinking the LED each line. "Button" reads the on-board USER switch (SW1, P1.02, active-low): press it (the SW1 button in the shared Controller panel) to turn the NeoPixel green and light the blue LED, release for dim red and the red LED — each edge prints over the console. Open the debugger, or add ?debug, to single-STEP real Thumb instructions from flash at 0x00000000, set PC breakpoints and write watchpoints, and read the ARM registers (r0-r15, xPSR, N/Z/C/V) and the real nRF52840 memory map live (FLASH 0, RAM 0x20000000, APB 0x40000000, GPIO 0x50000000). A bare Feather has no on-board speaker, so it is honestly silent.

Runs real compiled Adafruit Feather nRF52840 Express firmware on an in-browser Nordic nRF52840 (ARM Cortex-M4F, 64 MHz). The default "NeoPixel Rainbow" is a bare-metal C program that cycles a smooth rainbow on the single on-board WS2812 NeoPixel (P0.16), blinks the red user LED (P1.15) as a heartbeat, and announces each colour over the UARTE0 serial console — so the board lights AND prints out of the box. The NeoPixel colour is REAL: the program bit-bangs the 800 kHz WS2812 one-wire protocol on P0.16 and the board decodes the HIGH-pulse widths into a live RGB value (a long LOW latches the frame). "Blink" alternates the red (P1.15) and blue CONN (P1.10) LEDs with the nRF52 GPIO OUTSET/OUTCLR registers. "UART Hello + Counter" brings up UARTE0 (TX on P0.25) and prints a greeting and an incrementing four-digit counter to the serial console using a real EasyDMA transfer, blinking the LED each line. "Button" reads the on-board USER switch (SW1, P1.02, active-low): press it (the SW1 button in the shared Controller panel) to turn the NeoPixel green and light the blue LED, release for dim red and the red LED — each edge prints over the console. Open the debugger, or add ?debug, to single-STEP real Thumb instructions from flash at 0x00000000, set PC breakpoints and write watchpoints, and read the ARM registers (r0-r15, xPSR, N/Z/C/V) and the real nRF52840 memory map live (FLASH 0, RAM 0x20000000, APB 0x40000000, GPIO 0x50000000). A bare Feather has no on-board speaker, so it is honestly silent.