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microcontrollermicroprocessors24-bit

Why 24 bits registers?

In my work I deal with different micro-controllers, micro-processors and DSP processors. Many of them have 24-bits registers and counters.

I know how to use them, this is not my question.

My question is why do they have 24-bits register! why not make it 32 bit? and as I know, it is not a problem of size, because the registers are already 32bits, but have maximum of 0xFFFFFF.

Do this provide easier HW implementation? Faster calculations? Or it is just "hmmm, lets put 24-bits registers to make the job of programmers more hard"?

Solution

  • My guess is that most DSP applications simply don't need 32-bits. Digital audio uses 24-bits fidelity the most. Implementing 32-bits would require more transistors thus would result in higher costs.

    Why would 32 bits be easier for the programmer?

    Also, you state that the registers have a maximum of 0xFFFFFF, which makes them 24-bits by definition, not 32-bits as you suggest.