Hi, i am sandeep from andhra pradesh. i am very much interested to learn 8051 programming and computer parallel port programming. i am doing b tech second year. i searched in google but its of no use. can u suggest me any.... as i want to learn simple programs to control servo motor.
You need resistors on each segment to limit the current of each segment individually.
You can't just put one resistor in the common node or the limited current will be distributed between all the turned on segments; the segments would get dimmer as more segments are turned on because the current is shared between them all.
That is incorrect; it's irrelevant whether you scan of not. When you multiplex, you are turning on one common at a time. If you put the resistor in the common, the current in that digit will be divided between each of the segments that are on during that scan. You will notice the number '8' is the dimmest number and '1' would be the brightest.
If you multiplex (as you should with more than one digit), there should be 7 resistors; one for each segment.
To clarify what I meant: If you mutiplex one digit, you only need one resistor as there is only one LED on at one time. If you have more than one digit then it is normal to use 7 (or 8) resistors, one per segment. Yes it increases code complexity but you just mask the byte you're outputting with a different single bit (one segment) and output it 8 times.
You said in your previous post that you only need one per digit; which implies that you are using more than one.
I guess in the rather odd instance that you had an application that uses only one digit and your goal was to save 6 or seven resistors at the expense of added code, then it can be done; but you could just as easily use a resistor network chip. Generally multiplexing displays is done to save ports on a controller.
nice work..........
29riteshkakkar 10 months ago
Segment 'e' has a lower resistor.
McGuywer 1 year ago
Yes it is !
seemantadutta 3 years ago
is your xtal 11059200 ?
captncaveman81 3 years ago
Yes, it is !
seemantadutta 3 years ago
is there anybody know how to use bascom software...where can i find a sample of progaramming using it
kruk2162 3 years ago
each lenguaje has its advantajes and disvantajes....
i use both...
zurioxsrl 3 years ago
Programming on asm or c?
K1000PL 3 years ago
ASM !!
seemantadutta 3 years ago
I'm programming on C it's easier and faster. And 8051 stays my favorite uC :)
K1000PL 3 years ago
@K1000PL 8051 is weak compared to Atmega.
McGuywer 1 year ago
speak english!!
PatheticFatcow 3 years ago
Hi, i am sandeep from andhra pradesh. i am very much interested to learn 8051 programming and computer parallel port programming. i am doing b tech second year. i searched in google but its of no use. can u suggest me any.... as i want to learn simple programs to control servo motor.
sandydude19 4 years ago
WTF did you use so many resistors on the 7 segment display. Isnt it a common anode ro shit?. waste of processor power
jaa93997 4 years ago
You need resistors on each segment to limit the current of each segment individually.
You can't just put one resistor in the common node or the limited current will be distributed between all the turned on segments; the segments would get dimmer as more segments are turned on because the current is shared between them all.
jjenson2006 4 years ago
You should only require one resistor per each digit if you're multiplexing that is!
hrford 3 years ago
That is incorrect; it's irrelevant whether you scan of not. When you multiplex, you are turning on one common at a time. If you put the resistor in the common, the current in that digit will be divided between each of the segments that are on during that scan. You will notice the number '8' is the dimmest number and '1' would be the brightest.
If you multiplex (as you should with more than one digit), there should be 7 resistors; one for each segment.
jjenson2006 3 years ago
To clarify what I meant: If you mutiplex one digit, you only need one resistor as there is only one LED on at one time. If you have more than one digit then it is normal to use 7 (or 8) resistors, one per segment. Yes it increases code complexity but you just mask the byte you're outputting with a different single bit (one segment) and output it 8 times.
hrford 3 years ago
You said in your previous post that you only need one per digit; which implies that you are using more than one.
I guess in the rather odd instance that you had an application that uses only one digit and your goal was to save 6 or seven resistors at the expense of added code, then it can be done; but you could just as easily use a resistor network chip. Generally multiplexing displays is done to save ports on a controller.
jjenson2006 3 years ago