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Altera_Forum's avatar
Altera_Forum
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13 years ago

Counter with Radix 12

Hi ! Im an engineering student and new to VHDL and Quartus, i can get my way around to some extend but im having difficulty understanding this specific problem. I would like to create a counter...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

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The rule as I see it is: decimal number * 10/12 => your new radix 12 value

--- Quote End ---

Not quite. In C: 


int decval = 1137 ;
radix12 nr12 ;
int i = 0 ;
while ( decval /= 0) {
    nr12 = decval % 12 ;
    decval  -= nr12 ;
    decval /= 12 ;
    ++i ;
    }

decval = 1137 will result in nr12[] = { 7 , A , 9 } (7 * 12**2 + A * 12**1 + 9 * 12**0 = 1137)

where 1137 * 10 / 12 gives us 947.5

If you translate the C-code in VHDL you will get confronted with the mod and the / operator generating quite a few dividers (and subtractors) if you keep the conversion combinatorial