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Zilog Z8 Encore simple setup

Discussion in 'Microcontrollers' started by DirtyLude, Sep 20, 2003.

  1. DirtyLude

    DirtyLude Well-Known Member

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    I know there's at least one other person out there playing with this uController. I'm having a hard time setting up a chip for programming.

    I'm having alot of success with the evaluation board, so I bought a few chips and I'm trying to set them up. This is my breadboard for powering the 40 pin DIP package.

    [​IMG]

    A. 3.3volt power I have coming from an adjustable voltage reg. There's also a small LED here as a power indicator.

    B. A test LED attached to port A to test wether a program I download to the chip actually works.

    C. Power and Ground to the chip. VDD power, VSS ground. Plus a .01uf decoupling cap.

    D. 10k pullup resistor on the RESET pin.

    E. 10k pullup for the DBG communications line

    F. 20mhz Ceramic Resonator attached XIN/XOUT far pins, ground centre pin.

    G. 2 ground wires, and the DBG interface wire. The red wire dropping off the bottom of the picture is supposed to come over here as well.

    My problem is that when I hook up the power, 4 AA batteries won't even supply enough current to light up the power LED. A single 9 volt will light up the LED, but it will slowly fade over 30 seconds. The power regulator starts to get hot fairly quickly.

    It's like there's a short somewhere. I've disconnected everything other than the chip to see if it's one of the supporting connections with no success. It's the chip itself that's sucking up so much power. I've checked the pin-out diagram multiple times to make sure I'm powering the right pins, but it looks good to me.

    Can anyone else see what's wrong? I'd hate to throw in another chip just to find out I've destroyed two chips.
     
  2. DirtyLude

    DirtyLude Well-Known Member

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    Hmm... I've noticed that the programmers reference sheet and the Encore user manual show the VDD and VSS pin opposite here. I have no way of telling which is the correct version. Does this sound like what would happen if I reversed power and ground? Could I have destroyed the chip by doing so?

    EDIT: I switched the leads and the power seems to be stable, now. I guess this is one of the problems with dealing with a new product.

    Stay tuned, cuz I'm sure the programming dongle isn't going to work and I'll ask about that, next.
     
  3. Exo

    Exo Active Member

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    Am i seeying things wrong or is the center pin of your Ceramic Resonator connected to VDD ?
     
  4. dave

    Dave New Member

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  5. Exo

    Exo Active Member

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    guess i was to late :), reversing VDD and VCC could indeed have destroyed the chip
     
  6. DirtyLude

    DirtyLude Well-Known Member

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    Okay, here it is so far, but the programmer is not able to connect or recognize the chip.

    [​IMG]

    I have power to pin one of the programming dongle, and ground to the next two. The signal wire is going to the bottom centre pin on the two row 6 pin connector.

    I wonder if this thing needs 5 volts instead of the 3.3 volts? I think it's using the max232 chip.
     
  7. DirtyLude

    DirtyLude Well-Known Member

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    Crap, thanks. I guess the next step is to try another chip and see if the communications works with it.

    I checked the evaluation board and it suplies 3.3 volts to the debug dongle, so that should be fine.

    I'll write Zilog and tell them to replace this chip. How can they screw up the Programmers Reference Sheet? Especially with something as important as this. Idiots.
     
  8. DirtyLude

    DirtyLude Well-Known Member

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    Okay, well, new chip, same problem. I can't access it with the DBG port.

    It might be my resonator. Is there any way to figure out without a o-scope wether it's actually oscillating or not? I guess, I'll try a traditional crystal and caps and see if that does anything.
     
  9. DirtyLude

    DirtyLude Well-Known Member

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    Okay, I found in the manual where it says the Z8e doesn't support RC networks or ceramic resonators as it's external oscillator. Which makes working with these things more expensive. Isn't that bizarre? It only supports crystals.

    Well, I have a 20mhz crystal here, but not the supporting 22pf caps, so this project is going to have to wait until next weekend.
     
  10. rtryon

    rtryon New Member

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    I spoke with Zilog about this issue and apparently, the series 1 (denoted by a 0 in the 2nd to last digit in the part number (e.g. eZ8F6401) doesn't support resonators, but the engineer I spoke with said he "believed", that the series 2 chips did.

    BTW, you should be using the next series chips as the series 1 chips are soon to be EOL.
     
  11. DirtyLude

    DirtyLude Well-Known Member

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    Well, this is bringing back an old post. If you notice, this post was last added to in August of last year. The 642 chips were not out then, and unfortunately are still not out. I have 2 engineering samples here of the 642, but no supplier stocks the 642, yet.

    Yes, the 640 does not support ceramic, and the new 642 chips only support 10mhz ceramic.

    For a working setup with crystal:

    http://z8encore.higginstribe.com
     

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