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MAX6955 package confusion... — Parallax Forums

MAX6955 package confusion...

NakNak Posts: 36
edited 2009-12-20 06:30 in Propeller 1
Hi all,

I recently picked up a MAX6955 LED display driver and am trying to i/f with my Propeller (hence making this post on-topic!). However I am mightily confused by the packaging vs. specs of this IC... I have in my hands a 40-pin DIP package, but the spec sheet describes a 36-pin package that looks like a DIP but is labelled something else, and a 40-pin square surface-mount package that is clearly not the droid I'm looking for...

I'm lost. Am I supposed to be working with one of the two pinouts below, or something completely different!?!

Edit: Photo of chip attached. smurf.gif

Post Edited (Nak) : 12/20/2009 1:43:52 AM GMT
Screen shot 2009-12-19 at 3.42.46 PM.png
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MAX6955-1.jpg
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Comments

  • hover1hover1 Posts: 1,929
    edited 2009-12-19 23:56
    It look's like it's not available in 40 Pin "rectangle" package. What I think you have is the 36 pin chip. Not normal pinout, but there just the same.they are the same chip.



    Jim
    Nak said...
    Hi all,

    I recently picked up a MAX6955 LED display driver and am trying to i/f with my Propeller (hence making this post on-topic!). However I am mightily confused by the packaging vs. specs of this IC... I have in my hands a 40-pin DIP package, but the spec sheet describes a 36-pin package that looks like a DIP but is labelled something else, and a 40-pin square surface-mount package that is clearly not the droid I'm looking for...

    I'm lost. Am I supposed to be working with one of the two pinouts below, or something completely different!?!
    Post Edited (hover1) : 12/20/2009 1:14:18 AM GMT
  • NakNak Posts: 36
    edited 2009-12-20 00:05
    Hey hover1: So, would you map the 36-pin layout pin numbers to the 40-pin package pin numbers? Thus moving 19 (V+) and 20 (OSC) to the left side of the package? Or would you expect the physical layout to be preserved, leaving pins 19-22 of the 40-pin package unconnected?

    PS: Is there a safe way to probe at the pins of an IC and tell if they're not connected to anything?
  • hover1hover1 Posts: 1,929
    edited 2009-12-20 01:18
    Count the pins first. Could be 36.

    I'm not understanding what you are asking. You would connect the pins of the Max device to the correct pins on the Propeller Chip.

    You have not·attached a schematic or PCB layout·that I think you might be refering to.
    · Nak said...
    Hey hover1: So, would you map the 36-pin layout pin numbers to the 40-pin package pin numbers? Thus moving 19 (V+) and 20 (OSC) to the left side of the package? Or would you expect the physical layout to be preserved, leaving pins 19-22 of the 40-pin package unconnected?

    PS: Is there a safe way to probe at the pins of an IC and tell if they're not connected to anything?
  • NakNak Posts: 36
    edited 2009-12-20 01:26
    Hi hover1: There is an attachment on my first post that shows the 36-pin DIP-looking package pinout and the 40-pin surface mount package pinout. This was copied straight from the Maxim spec sheet. What I have, though, is a 40-pin DIP package. I have counted the pins several times to be sure! I simply have no idea what pins do what on this 40-pin package.
  • hover1hover1 Posts: 1,929
    edited 2009-12-20 01:31
    Could you take a picture of the top of the chip?



    Jim


    Nak said...
    Hi hover1: There is an attachment on my first post that shows the 36-pin DIP-looking package pinout and the 40-pin surface mount package pinout. This was copied straight from the Maxim spec sheet. What I have, though, is a 40-pin DIP package. I have counted the pins several times to be sure! I simply have no idea what pins do what on this 40-pin package.
  • NakNak Posts: 36
    edited 2009-12-20 01:42
    Pic attached to first post. smile.gif
  • kuronekokuroneko Posts: 3,623
    edited 2009-12-20 01:51
    Seems that the APL variant comes in 40 pin PDIP.
    MAX6955.png
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  • NakNak Posts: 36
    edited 2009-12-20 01:54
    TY TY TY!!! Now I can finally get on to playing with my propeller! smile.gif
  • hover1hover1 Posts: 1,929
    edited 2009-12-20 06:30
    Good news!
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