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Basic Stamp to SN754410 — Parallax Forums

Basic Stamp to SN754410

Jared5755Jared5755 Posts: 26
edited 2006-04-29 03:15 in General Discussion
Eventually, I want to control a SN754410 with my basic stamp.· But, I can't seem to figure out something that should be very easy.
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I ordered some·SN754410's and can't get them to work. What I have tried is just applying +9v to pin 8 and grounding the supply voltage to pins 4,5,12,13. No other pins have anything hooked up to them. According to my power supply, the chip draws 3A when I do this. I know this isn't correct. I am positive there isn't a short in the circuit (I've even tried it on a breadboard). When I take the chip out and apply the voltage, nothing happens (as is expected). It's just when I plug in the chip. It's like there is a short inside the chip. I've actually tried a total of 12 chips!· Could the chips have been damaged? It seems to me that nothing should happen when I apply the voltage to pin 8. I've tried the same thing (using +5v) on pin 16, and again, the chip draws about 3A.
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Does anyone have any suggestions?
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Just to be clear on what I'm doing, here's the steps I have taken:
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Plug SN754410 into breadboard.Connect pins 4,5,12,13 togetherApply +9v to pin 8Connect gound to pin 4(chip draws 3A, even when above steps are taken with pins 16 and 5v)·Thanks a lot,Jared

Comments

  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-04-29 01:41
    · What happens with: ·+5V to both 8 and 16; 4, 5, 12, 13 to GND; and 1, 9 to GND (this last should put the outputs in Hi-Z)?

    · Can you turn your voltage up slowly from 0V and note the current as you increase it?

    · Then -- with 2 HI·& 7 LO and 10 HI·&·15 LO? [noparse][[/noparse]HI = +5, LO = GND]

    · Place a 10 kohm from 1 to +5V and a 10kohm from 9 to +5V and then remove the jumper from 1 to GND·and the jumper from 9 to GND.· This will enable the outputs.·
  • Jared5755Jared5755 Posts: 26
    edited 2006-04-29 03:15
    Thanks a lot for the help. I wired it up the way you describe and tried a brand new chip. It worked! I plugged in some of the other ones I was trying, and they acted like they did before. So, I must have gotten some bad ones. It's strange because I just got these in the mail and they came in an antistatic bag and everything. I'm really glad it's working now. I need to get on to the hard things.

    Thanks
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