Arduino Forum

Using Arduino => LEDs and Multiplexing => Topic started by: Flub on Apr 12, 2011, 08:54 am

Title: Serial -> 7 - Segment display
Post by: Flub on Apr 12, 2011, 08:54 am
Hey there,
I try to control 4 7 segment displays with two of these registers http://www.alldatasheet.com/datasheet-pdf/pdf/51041/FAIRCHILD/DM74LS164N.html

I connected the reset pins, the clock pins, and on both of them I connected serial in 1 and 2 .
the serial in inputs of the second one are connected with the last output (OH) of the first register.

Now I cannot figure out how to send serial data to it from the arduino.
Which is the clock pin, which is the serial out pin, how can I access them?

(http://yqezpq.blu.livefilestore.com/y1pAnUbSEMiGl5L9ZzOleeDb8SA7Qg7PLgyTASzuOewOBsaTQYKb3aahLTCdWYhfqBb0doAw8ONobWogi7CjHyw2g/PIN%20MAPPING%20ARDUINO%20MEGA.jpg)

I really dont know how i can get this work  :~

- Flo
Title: Re: Serial -> 7 - Segment display
Post by: Grumpy_Mike on Apr 12, 2011, 09:33 am
Quote
Which is the clock pin, which is the serial out pin, how can I access them?


Any pin you want them to be, it is down to your software.

See :- http://www.arduino.cc/en/Tutorial/ShiftOut (http://www.arduino.cc/en/Tutorial/ShiftOut)

Note that for four 7 Segment displays you will need four shift registers not two.
Title: Re: Serial -> 7 - Segment display
Post by: Flub on Apr 12, 2011, 10:29 am
i got it to work now.

it was just a the and gate input of the registers.
I need two 8 bit registers, or four 4bit ...

it works now
Title: Re: Serial -> 7 - Segment display
Post by: Grumpy_Mike on Apr 12, 2011, 10:37 am
Quote
it was just a the and gate input of the registers.

Not sure that make any sense.

Quote
I need two 8 bit registers, or four 4bit

? a seven segment display has seven segment hence you need seven outputs. Unless of course you don't actually have a seven segment display but a decoder chip driving the seven segment display, which is something different from what you said.
Title: Re: Serial -> 7 - Segment display
Post by: Flub on Apr 12, 2011, 01:04 pm
yeah sorry,  i meant that there is  an AND gate at the inputs of my serial in parallel out shift registers.

and yeah i meant driving the drivers...

i was just so happy that it finally worked ...

- Flo