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# Direct Decimal to Binary Address Generator for Small Memories

IP.com Disclosure Number: IPCOM000092875D
Original Publication Date: 1967-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 28K

IBM

## Related People

Lengyel, EJ: AUTHOR [+2]

## Abstract

This translator directly converts a decimal number, represented, for example, in a two out of five code, to a binary number not necessarily the mathematical equivalent of such decimal number. The binary number is used to set the memory address register MAR of a memory.

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Direct Decimal to Binary Address Generator for Small Memories

This translator directly converts a decimal number, represented, for example, in a two out of five code, to a binary number not necessarily the mathematical equivalent of such decimal number. The binary number is used to set the memory address register MAR of a memory.

The units position 10 of any decimal number, having 0 to 7 in such position, is directly converted by decimal to binary translator 12 to its binary equivalent in MAR. Any decimal number ending in 8 or 9 is not directly converted, so these two digit positions are handled separately. The units position 8 sets the MAR binary positions 16 and 64. The units position 9 sets the MAR binary positions 32 and 64. The tens position 16 of the decimal number is translated by translator
18. All addresses not ending with 8 or 9 in the units position of the decimal number are thusly translated directly from decimal to binary. Decimal addresses ending in 8 or 9 in the units position cause Or 22 to be energized.

The output of Or 22 energizes And's 24 and deenergizes And's 28. This causes the output of the decimal to binary translator 18 to be switched to the 1, 2, and 4 positions of MAR instead of the 8, 16, and 32 positions. This circuit does not always give the mathematical equivalent of the decimal number in binary, but it does give a unique address in binary for each decimal number when the numbers to be converted are small.

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