BitBench

Firmware practice without the noise.

Embedded C problems, systems prompts, and fundamentals in a quiet workspace built for firmware engineers.

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problems: 101
topics: 10
workspace: C11

solution.cC

RunSubmit

1#include <stdint.h>

3#define GPIOA_BSRR (*(volatile uint32_t *)0x40020018)

5// Drive PA5 high — atomic set via the BSRR register

6void led_on(void) {

7 GPIOA_BSRR = (1u << 5);

8}

Accepted

2 ms132 KB

01sets the target bit
02preserves neighbor bits
03atomic write

Practice

Pick the interview surface.

Coding is one part of the loop. The rest is architecture, debugging, and fundamentals under pressure.

Topics

Built around real low-level work.

Embedded C

Pointers, volatile, fixed-width types, and the C that runs on metal.

Bit Manipulation

Masks, shifts, and register flags without disturbing neighbors.

Memory-Mapped I/O

Drive peripherals through volatile register pointers.

Communication Protocols

UART, SPI, and I2C framing, parsing, and checksums.

RTOS

Tasks, ISRs, atomicity, and shared-state race conditions.

Debugging

Inspect broken firmware and explain the root cause.

State Machines

Non-blocking timing, debouncing, and protocol framing.

Bootloaders

Image integrity, CRCs, and safe OTA update flows.

Systems Design

Architect firmware: schedulers, drivers, and recovery.

Memory Management

Static allocation, pools, and fragmentation-free design.

Flow

Read. Write. Run. Review.

Read the spec

Each exercise starts from a focused embedded problem statement, not a puzzle wrapped in a story.

Write embedded C

Use the in-browser editor for register work, buffers, protocols, and small systems code.

Review the result

Run against a stable judge contract and see the failure point without leaving the page.

Example

A problem should read like a real spec.

Short statement. Clear signature. Examples you can verify.

EasyBit Manipulationaccount required

Set, Clear, and Toggle Register Bits

Modify a single bit of an 8-bit hardware register using masks — without touching the others.

Function signature

uint8_t set_bit(uint8_t reg, uint8_t bit);
uint8_t clear_bit(uint8_t reg, uint8_t bit);
uint8_t toggle_bit(uint8_t reg, uint8_t bit);

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