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Thread: 74HC595N shift register in Eagle Lite

  1. #1

    Default 74HC595N shift register in Eagle Lite

    I have in the process of transferring a fully breadboarded project to Eagle Lite so I can produce a PC board, and to document the project for this group.

    I am almost finished, but am stuck on adding the 74HC595N shift register that I needed because I simply ran out of I/O pins on the Basic Stamp 2.

    When I insert the 74HC595N chip in Eagle Lite, the component is shown without pins 8 and 16. I have pin 8 wired to Vss and 16 to Vdd on my test setup. I notice Vdd is also connected to pin 10 and Vss to 13.

    Can I do without connecting pins 8 and 16? And therefore use to Eagle Lite 74HC595N component in my circuit diagram. Or should I try and track down another 74HC595N component for Eagle Lite that does show the 8 and 16 pins? The Stampworks manual shows pins 10 and 16 connected to Vdd and pins 8 and 13 to Vss.

    This is my first attempt at a "real" project with the Basic Stamp, so be gentle with me. FYI it is an irrigation controller that uses a moisture probe to determine when and how much to irrigate. It also knows the local water restriction rules and shifts it's watering times accordingly, or switches off completely in order to comply. An LCD display shows the current date and time and water restriction stage, and three momentary contact switches allow the user to change the date, time and restriction stage. Also the system will only ever water the lawns and garden beds in the cool of the evening, further reducing the amount of water required. The aim of the project is to irrigate at little as possible. Water is becoming a scarse commodity in this country (Australia).
    Last edited by ForumTools; 10-01-2010 at 02:47 PM. Reason: Forum Migration

  2. #2

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    Eagle has the ability of hiding the power connectors in the schematic, by tying the supply to the special power symbols it will make the appropriate connections in the board layout. If you find this doesnt occur let me know, and Ill see if I can help you fix it.

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    1+1=10
    Last edited by ForumTools; 10-01-2010 at 02:47 PM. Reason: Forum Migration

  3. #3

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    Thanks Paul!

    That's pretty tricky. Like I say, I'm very new at this. I'll see what Eagle does with the 8 and 16 pins on the board layout.

    It'll take me a while to layout this board. I have a BS2, the 74HC595N, a DS1307 RTC, 6 MOC3021M optoisolators, 6 BT139 triacs, a few switches and headers, a DC power supply plus loads of resistors and capacitors! There is no way I'd want to do this project without a custom PCB - it'd be a wiring nightmare!
    Last edited by ForumTools; 10-01-2010 at 02:47 PM. Reason: Forum Migration

  4. #4

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    BTW sparkfun.com is a great place to do PCB prototype boards, $10+$2.50/sqin. The boards aren't the highest quality possible, but they do the trick, especially for the price.

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    1+1=10
    Last edited by ForumTools; 10-01-2010 at 02:47 PM. Reason: Forum Migration

  5. #5

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    Thanks Paul.

    THE PLAN is to print the PCB layout onto transfer film, and then etch the circuit myself!

    What could go wrong?
    Last edited by ForumTools; 10-01-2010 at 02:48 PM. Reason: Forum Migration

  6. #6

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    Bullwinkle said:

    "What could go wrong?"

    Drilling lots of teeny tiny little holes..

    ;^)

    TDP

    Post Edited (tperkins) : 5/5/2006 12:53:38 PM GMT
    Last edited by ForumTools; 10-01-2010 at 02:48 PM. Reason: Forum Migration

  7. #7

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    Yeah, getting the holes right is the hardest part when doing the PCB yourself. A close second is if you are doing dual side, lining up the two patterns so the vias match up.

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    1+1=10
    Last edited by ForumTools; 10-01-2010 at 02:48 PM. Reason: Forum Migration

  8. #8

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    I've got a drill press, that should help. I guess I just need a very small drill bit to attach to my high speed drill.

    BTW - The "what can go wrong"? comment was a joke. I know there is many ways to screw this up!

    I'm just trying to be optimistic.
    Last edited by ForumTools; 10-01-2010 at 02:48 PM. Reason: Forum Migration

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