interfacing PIC to 4511 and ICs

[mikedf]

Hello,

I found this forum while I was trying to find an answer to this question and i thought I would give it a shot. I have a scoreboard without any kind of controller to input scores, so it is worthless unless I modify it. I have opened it up, it has a suitable power supply and circuitry to control the digits. It uses a 4511 to convert BCD to the seven segment display logic (which is hooked to transisters and then to the display itself). I have expirence programming the PIC16F684, and from that standpoint this looks like cake. So basically all I need to do is to cut the trace to the chips and hook up a pic to output bcd and the latch signal (2 4511 chips and displays for each PIC). My only issue is interfacing the PIC to the two 4511. I think what I need to do is hook 4 IO from the pic to the ABCD inputs of both 4511 and 2 more IO to each of the latch inputs. In my mind it seems easy, but when I look at the circuitry that already exists to control the chips it seems alot more complicated. Do I need to put resistors between my pic IO and the 4511 or something? How about resistors from the IO to +5v? these things seem to be in place for the old circuitry.

 

[Pommie]

You should be able to use the same 4 IO for the BCD to both 4511s and two separate IO for the 2 latches. You then put the value on the BCD pins and toggle the appropriate latch IO. As long as the circuitry is running at 5V then it should work fine. If it's higher then you may need additional circuitry.

Mike.

 

[mikedf]

yeah thats what my plan was, 6 IO total, which leaves me with plenty of room for inputs.

so all i have to do is connect the correct IO pin to the bcd/latch input of the chip if everything is running at 5 volts? no resistors? this project is gonna be easier then I thought.