binary to bcd decoder

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jacuinde

New Member
i have a problem, im representing a analog signal that im converting it to digital, then when i try to display on a 7 segment display with a 7448 bcd driver, a 10, i want it to turn to 0 and that in another display it gives me a 1, how can i do it?

samcheetah

New Member
first of all i dont understand the subject.

binary to bcd decoder

BCD is binary coded decimal. so BCD is actually an encoded form of binary. u cant decode binary to bcd. although u can decode bcd to binary.

regarding to your question. im sorry its hard to understand what u r asking. are u asking how to display 10?? for that u should have two BCD lines driving two displays. one will have the code for zero (0000) and the other will have the code for one (0001).

i hope that helps

Roff

Well-Known Member
samcheetah said:
first of all i dont understand the subject.

binary to bcd decoder

BCD is binary coded decimal. so BCD is actually an encoded form of binary. u cant decode binary to bcd. although u can decode bcd to binary.
This is only true if your number is 9 or less. Otherwise, you must decode if you want bcd.

11011011 (binary) = 219 (decimal) = 0010 0001 1001 (bcd). That requires a decoder.

samcheetah

New Member
This is only true if your number is 9 or less. Otherwise, you must decode if you want bcd.

11011011 (binary) = 219 (decimal) = 0010 0001 1001 (bcd). That requires a decoder

isnt that called encoding??????????

Roff

Well-Known Member
Isn't that called semantics? I thought you were implying that no logic transformation (encoding, decoding, transmogrification, whatever) was required to get from binary to BCD.

samcheetah

New Member
Isn't that called semantics? I thought you were implying that no logic transformation (encoding, decoding, transmogrification, whatever) was required to get from binary to BCD.

no i didnt say that. i said

BCD is binary coded decimal. so BCD is actually an encoded form of binary. u cant decode binary to bcd. although u can decode bcd to binary.

when u transform one thing into something else, it is called encoding and when u transform it back to that thing it is called decoding. so when u transform binary into BCD, u r encoding binary into BCD. so BCD is an encoded form of binary. now when u transform BCD to binary u are decoding BCD to get the equivalent binary. the person who asked the question wrote "binary to BCD decoder" in the subject. so i told him that he was not right.

i think we should not argue on semantics and rather try to answer his question.

i told that im sorry i dont understand the question. but i did try to answer the question from what i understood.

Russlk

New Member
One way to do it would be to similtanously clock BCD and binary counters. When the binary numbers are equal, you can read the BCD counter.

Roff

Well-Known Member
samcheetah said:
Isn't that called semantics? I thought you were implying that no logic transformation (encoding, decoding, transmogrification, whatever) was required to get from binary to BCD.

no i didnt say that. i said

BCD is binary coded decimal. so BCD is actually an encoded form of binary. u cant decode binary to bcd. although u can decode bcd to binary.

when u transform one thing into something else, it is called encoding and when u transform it back to that thing it is called decoding. so when u transform binary into BCD, u r encoding binary into BCD. so BCD is an encoded form of binary. now when u transform BCD to binary u are decoding BCD to get the equivalent binary. the person who asked the question wrote "binary to BCD decoder" in the subject. so i told him that he was not right.

i think we should not argue on semantics and rather try to answer his question.

i told that im sorry i dont understand the question. but i did try to answer the question from what i understood.
OK, sorry that I misunderstood you. I generally agree with your definitions of encoding and decoding, although a Google search for "binary to BCD decoder" produced a page of hits - so I'm not the only idiot. :?
The binary to BCD converters I have seen require a microcontroller or microprocessor. There was a TTL part, 74185, but it seems to have been discontinued.
If you had a multi-digit BCD counter, and you converted the output to binary, would that be called an encoder or a decoder? I think perhaps "converter" is a better term, no matter which way you are going.

samcheetah

New Member
OK, sorry that I misunderstood you.

thankyou

The binary to BCD converters I have seen require a microcontroller or microprocessor. There was a TTL part, 74185, but it seems to have been discontinued.

so it does exist :?

If you had a multi-digit BCD counter, and you converted the output to binary, would that be called an encoder or a decoder? I think perhaps "converter" is a better term, no matter which way you are going.

this just keeps on getting harder and harder. ill agree with u

Nigel Goodwin

Super Moderator
I think one of the biggest problems in this thread is the use of 'BCD', I'm not exactly sure what is wanted - but I presume it's to display a binary number as decimal, so if it's an 8 bit binary number you want the display to go from 0-255.

If this is so, it's nothing to do with BCD at all, BCD isn't a method of displaying a binary number, it's a way of doing decimal maths in a binary system. With BCD your 8 bit number could only go from 0-99 in decimal, or 0000000-10011001 in binary, many processors have BCD maths capability.

Remember, BCD means 'Binary Coded Decimal'.

Perhaps jacuinde would like to give more details of exactly what he's trying to do?, in particular how many bits are being used, and how he wants them displaying.

samcheetah

New Member
Nigel i think the biggest problem in this thread is that jacuinde is silent :lol:

i think he isnt using any processor. he might just have BCD from discrete logic ICs. i think that he wants to display two digit numbers. and he is asking that how would the second digit be displayed. it could have been that he encoded binary into BCD and now he wants to display it on a two digit display.

but all of that depends on jacuinde's reply

ljcox

Well-Known Member
jacuinde said:
i have a problem, im representing a analog signal that im converting it to digital, then when i try to display on a 7 segment display with a 7448 bcd driver, a 10, i want it to turn to 0 and that in another display it gives me a 1, how can i do it?

I'm not sure that I understand your question. If you simply want to convert 10 (meaning ten) into a 0 (ie. binary 0000), with a 1 for the tens display, then it can be done very simply with gating.

But why is your a/d converter giving you as 10 instead of a 0?

Len

cucumber

New Member
binary to bcd converter

i have inputs in 4 bit binary ( from 0 to 15). i want to display my 4 bit binary inputs to 7 segment display which means i must have two 7 segment display. how can i convert my binary inputs to bcd in simplest way? can anyone give me explaination on how to make both of my 7 segment display the outputs of two digits ( from 00 to 15)?

-thank you

RAPIDRICK

New Member
I think I know what jacuinde is asking because i have a similar question. Say that you have an 8 bit AD converter, and you want to display it's full range of base 10 values, that is 1 through 256. Is there a chip that will take this 8 bit number and decode it to a 3 digit display. I know that the 7448 (BCD-to-seven-segment decoder/driver) will take a 4 bit binary number and convert it to hexidecimal:0 through 9 and A through F (on a one digit display). Jacuinde wants to take a 4 bit number and display 0 through 15 (using a 2 digit display). Is there a decoder chip similar to the 7448 that will do this?

RAPIDRICK

New Member
One addendum. I just noted that jacuinde asked this question 4 years ago. Is anyone out there?

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