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Recent content by R2D1

  1. R

    [SOLVED] Project to replace CY7C64613 in the ICD2

    Hi bendjy, Thanks for your great help!!! Now I have enough info to create my own custom clone. :D
  2. R

    [SOLVED] Project to replace CY7C64613 in the ICD2

    Hi bendjy, Thanks for checking. I checked my downloaded schematic and found the icd2_2.jpg very much like what you said. Searching this thread and found the post by stroma and your reply in page 12: Is icd2_2.jpg correct after replacing NAND gate with AND gate? Is the resistors value correct...
  3. R

    [SOLVED] Project to replace CY7C64613 in the ICD2

    Could anyone with original ICD2 check the circuit on RC3 (37), RC4 (42), RC5 (43) of 877A? I would like to confirm the original buffer design. Thanks a lot!
  4. R

    [SOLVED] Project to replace CY7C64613 in the ICD2

    Potyo: I can read your pdf using Acrobat 5. Question: Why use 2 buffer on both PGC & PGD? Also, don't quite understand the function of 4066 in your design. Suggestion: Use 74LVC8T245 or 74LVC2T45 to replace 74HCT125 & 74AHC126.
  5. R

    [SOLVED] Project to replace CY7C64613 in the ICD2

    Lothar: Thanks for the idea, but the technique could not be used with the buffer in place. When the buffer switched to out direction, the 877 will read the state of buffer input, rather than the state of the target PGD. Could it be for satisfying the PGD setup time using hardware? So as to...
  6. R

    [SOLVED] Project to replace CY7C64613 in the ICD2

    Polymath: I quote the wrong phrase. What I mean is the target will not see the VPP when it ramp up/down as long as the transistor is off, so no risk of damage from transistor circuit. I agree the DG411 is better, but those already built the transistor design should not be worried. You are...
  7. R

    [SOLVED] Project to replace CY7C64613 in the ICD2

    This thread is so active, need to catch up. Polymath: Thanks for the link. The design of 0430_004 is not optimized (such as NAND gate), I can believe it is the first clone, but can't believe it as the original circuit. The 3.3V debug thread is a good one, the choice of different logic family...
  8. R

    [SOLVED] Project to replace CY7C64613 in the ICD2

    Andy: Comparing to 0430_004.pdf, it seems you didn't connect P.14 of DG411, so only 1 switch for VPP path. Why use 2 switches for VPP? I can only think of reducing 'on' resistance. But that seems to contradict with Lothur's suggestion of limiting inrush current, and NICK7's design of adding 1K...
  9. R

    [SOLVED] Project to replace CY7C64613 in the ICD2

    Yo, I post the question just to earn enough points to get Andy's file, didn't expect so many quality posts in a few days. :D The original ICD1 already use the simple switcher approach plus a 78L12 to give a fixed VPP. The PICKit 2 uses exactly the same approach to get a variable VPP. May be...
  10. R

    [SOLVED] Project to replace CY7C64613 in the ICD2

    Hi Everyone, Thanks for the good work for making this clone possible. Most of the design in this post are simplified version. Just wonder has anyone include the d-pot in this ICD2? Regards.
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