Hardware method to convert BCD to binary Which approach is commonly used to implement a BCD-to-binary conversion purely in hardware (without firmware/software)?

Introduction / Context:
BCD-to-binary conversion can be implemented in hardware for speed or simplicity, especially in older or minimalist embedded systems. Medium-Scale Integration (MSI) devices—such as adders, multiplexers, small ROMs/PLAs, or dedicated converter ICs—offer practical gate-level solutions for translating BCD digits into a binary number without using a CPU or microcode.

Given Data / Assumptions:

• We need a hardware-only conversion path from BCD to straight binary.
• MSI building blocks (adders, counters, ROMs) are available.
• No reliance on serial peripherals or software routines.

Concept / Approach:

One method is to use adders and shift/weighting logic: binary = 10 * tens + ones (and extend for more digits). Another is to employ a small ROM/PLA that maps BCD inputs to binary outputs. Both are classic MSI techniques. Devices like keyboard encoders or UARTs do not perform numeric base conversion; an ALU could, but typically belongs inside a CPU, not as a simple MSI “hardware approach.”

Step-by-Step Solution:

Verification / Alternative check:

Historical designs and application notes show 74xx adders and multiplexers used for code conversions; small PROMs were also popular as fixed translators.

Why Other Options Are Wrong:

Keyboard encoder: converts key matrix positions to codes, not BCD-to-binary arithmetic.

ALU: generally part of a processor; while possible, it is not the simple hardware-only MSI pathway implied.

UART: handles serial-to-parallel and framing, not numeric base conversion.

Common Pitfalls:

Ignoring invalid BCD inputs (1010–1111); proper designs must detect or map them safely.

Final Answer:

with MSI IC circuits