Willem EPROM programmer?

Discussion in 'General Electronics Chat' started by john beard, Feb 9, 2015.

  1. john beard

    Thread Starter New Member

    Feb 9, 2015
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    Hi everyone. I'm the new guy. My question is I bought a Willem EPROM programmer , at least that what I was told. No manual , no markings on the board to tell me anything. I've looked it up and found some that look like it but mine only has the USB for power. In the corner it has a number 330/35 on it. Can someone help out and tell me where to get the right software too. Thanks.
     
  2. john beard

    Thread Starter New Member

    Feb 9, 2015
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    Here's a pic of it.
     
  3. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    Did you try Google?

    Looks like it has a parallel port connector on it. Windows has trouble with those things now a days.
     
  4. john beard

    Thread Starter New Member

    Feb 9, 2015
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    Yes I have that's why I came here.
     
  5. jgessling

    Active Member

    Jul 31, 2009
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    You might try posting your query to the cc talk mailing list. You don't need to join. Go to classiccmp.org to see how to submit a message and then watch for replies on the archives. This group specializes in older computer so EPROM programmers are often discussed. Good luck.
     
  6. takao21203

    Distinguished Member

    Apr 28, 2012
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    its a Centronics port. The technology is no longer needed = deprecated.
     
  7. jgessling

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    Jul 31, 2009
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  8. john beard

    Thread Starter New Member

    Feb 9, 2015
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    I looked there. That's not it either. Mine doesn't have the second power hook up. Just the USB . I guess that's what I get for going cheap.
     
  9. ian field

    Distinguished Member

    Oct 27, 2012
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    Anything old enough to have a Centronics port probably doesn't support the more recent EPROM capacities.

    A good source of free reprogrammable ROM is old PC motherboards - they switched to using FLASH EEPROMs quite some time before 16 bit ISA slots became extinct.
     
  10. john beard

    Thread Starter New Member

    Feb 9, 2015
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    What is a centronics port ? The place where you hook the parrell cable too, is that what you are referring to. Mine is just like all the other ones I've seen. I'm trying to find what model it is so I know which version software to get?
     
  11. dl324

    Distinguished Member

    Mar 30, 2015
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    Hi John,

    Unfortunately, you've purchased the infamous "Enhanced Universal Willem EPROM Programmer". In my experience (I have one), it is unusable for reading or writing EPROMs.

    That being said, you can download software from sivava.com. I'd start with version 0.97ja http://www.sivava.com/downloads#/0.97ja-tags/sort=p.sort_order/order=ASC/limit=15

    It's been awhile since I've thought about that programmer, but I do recall that that design uses the output of an OP AMP to supply some of the voltages. Because of that, it can only provide about 25mA of current.

    Because they typically sand the part numbers from the IC's on that variant, it's difficult to modify. But, as I said, that particular variant is useless. Nice idea, but they failed on the implementation.

    BR
    Dennis
     
  12. dl324

    Distinguished Member

    Mar 30, 2015
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    Hi John,

    Here's a link with some information on your programmer. It was originally posted on willem.org, but that site is defunct (after Willem passed away). EZo resurrected some of the old posts and is hosting them read-only on his website (ezoflash.com).

    http://www.ezoflash.com/willem_info/forum.php?show=topic&topic=1145286403

    I am the user DL in those postings. I used to be an administrator on willem.org.

    BR
    Dennis
     
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  13. john beard

    Thread Starter New Member

    Feb 9, 2015
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    Yes after searching Google for awhile I found out that it was indead the enhanced willem and I can't use it for what I need. What's a good EPROM programmer for m27c1001 chips.
     
  14. dl324

    Distinguished Member

    Mar 30, 2015
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    Hi John,
    If you're going to program enough EPROMs to justify not having someone else program them for you and you want to stay with an inexpensive Willem based programmer, any PCB3 variant, ATH3.1, or Willem 4.1 can be made to work. Just understand that all PCB3 variants use a step up regulator to generate VPP and they opt for an inexpensive molded inductor that saturates at a low current. That means they struggle to produce VPP > 12.5V, some even struggle to provide 12.5V.

    The only Willem variant I would consider buying is the 4.1 which has a relay to switch VCC so it can handle NMOS EPROMs (2716, 2732, etc) and higher capacity CMOS EPROMs (larger than 1Mb). Unfortunately it's no longer available commercially. I sold Willem's programmers in the US and have small number of bare boards I'd sell at cost if you're interested in assembling your own. All of the components needed should be readily available; most of what you need is on the programmer you purchased.

    Since Willem programmers are hobbyist level, they assume you know something about programming EPROMs so you can do it reliably. I'd be happy to answer any questions you might have.

    HTH,
    Dennis
     
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  15. john beard

    Thread Starter New Member

    Feb 9, 2015
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    Is their another brand you would consider.
     
  16. dl324

    Distinguished Member

    Mar 30, 2015
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    Hi John,

    I don't have any recommendations for other programmers. Willem programmers satisfy my needs; though I would like software to be more open so the algorithms can be examined. I work around that unknown by verifying programmed devices at several voltages (all mentioned in typical programming algorithms).

    Paying hundreds of dollars for a commercial programmer doesn't necessarily mean it programs devices reliably. I had a "professional" EPROM programmer and discovered the hard way that it didn't verify erase margin correctly. When I contacted the company, they just told me my model was obsolete and that I should purchase a newer model.

    BR
    Dennis
     
  17. john beard

    Thread Starter New Member

    Feb 9, 2015
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    Are the newer Willem EPROM boards any good , like the version 5 with the extra power adapter
     
  18. dl324

    Distinguished Member

    Mar 30, 2015
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    Hi John,

    Like most things, it depends. It depends on whether they've improved the power supply circuitry which has been a weakness in most Willem programmers and what devices you want to program. I would ask the Seller if the programmer can provide VCC and VPP at the required voltages and currents for reading/programming devices. For VCC, I'd check for 4.2, 5.0, 6.0, 6.25 with a drop of 0.1V or less at 50mA. For VPP, I'd check for 12.75, 21.0, 25.0 with a drop of less than 0.25V at 50mA. If they say they can program NMOS EPROMs, they need to be able to provide VCC at 100mA. If you buy one that can't do this, return it as it's unsuitable for use as a programmer.

    Proper programming of a 5V (10% tolerance) 27C512 requires VCC options of < 4.5V (for blank checking), 6.25V (for programming), and 5V at a minimum current of 50mA. Many devices will not require the maximum current from the specs, but the programmer should be designed for worst case so that all will program reliably. All Willem type programmers I've seen (except the Willem 4.1) use a transistor to switch VCC. At 50mA, Vce(sat) will be 0.5V to a couple volts and that's a problem. If programming VCC is 6.25V, but you get a half volt drop in the transistor switch, the device being programmed only sees 5.75V. That means you're only checking program margin to 5.75V. If the EPROM has a 10% supply tolerance, it could be operated at 5.5V. If the circuit was in an electrically noisey environment, you could get spikes on VCC which could make it briefly exceed the programming margin check voltage and you wouldn't have verified that it would operate above the VCC used for programming. One thing to be aware of is that all of the PCB3 variants I've studied used signal diodes to increase/decrease the nominal VCC. The voltage drop of a diode is non-linear and varies with forward current, so for low VCC you can get a tenth of a volt from the diode used to reduce VCC from the switch; in addition to the drop in the switch. The lowest VCC I've seen suggested from a manufacturer for a 10% tolerance 5V part is 4.2V. The part is guaranteed to operate at 4.5V, but the erase margin voltage is lower than that. I wouldn't go below the minimum specified by the manufacturer and expect reliable operation.

    VPP generation has typically been a problem on PCB3 variants (PCB4.5, PCB5, PCB6, etc). They use a step up regulator to generate VPP, but many designs use a molded inductor that saturates at a low current. They also use a transistor to switch this voltage, but this is less critical if you do program verification at 4.2V, 5.0V, and 6.25V. What matters is the amount of charge deposited on the floating gate, not the programming voltage (within reason). So if VPP was specified as 12.75V +/- 0.25V and you dropped a volt below minimum, you could still get enough program margin.

    When I've used PCB3 variants, I replace the VCC and VPP circuitry with something more robust. I always replace the step up regulator with a linear regulator. It means I need to use a different adapter, but I'm more confident that the voltage will be stable. On my most robust modifications, I included remote voltage sensing for VCC to compensate for any voltage drops 100mA could cause in the connection to the programmer.

    I've read of some who thought simply programming the device several times would compensate for voltage issues. This might not work in all cases.

    HTH,
    Dennis
     
  19. john beard

    Thread Starter New Member

    Feb 9, 2015
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    So I guess my best bet is to find someone who program chips for me on acasion when I need them done.
     
  20. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    Or get an ancient DOS computer with a parallel port.
     
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