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martin
USA
6 Posts |
 Posted - 12/13/2006 : 16:11:33
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I've spent some time debugging programming 27C322s, and learnt a lot about Willems. I have the usb powered Willem, and the True USB Willem - the True USB device is very superior!
1) Some EPROMs require more than 5V. As USB is only 5V, you are out of luck unless you jigger up a special USB power supply. I was able to program an EPROM by finding a computer that ran at 5.06V instead of 4.9V. Not what I really wanted, but it got me through.
The True USB programmer has a second voltage converter that generates the higher Vcc under program control.
2) The True USB Willem is way faster. Presumably because of all the bit banging on the parallel port, which eats my processor on the parallel Willem.
3) Support is very good. They have solved my problems quickly - and the fixes roll through into the next release.
Now, enhancements I would like:
Programmatic parameters in the device control list:
tWP; tWC - these we know from Willem, write pulse length and
cycle delay.
Vv1; Vv2 - verify voltage 1 and verify voltage 2 for margin
test. Verify all bits at each voltage. 5V default if not listed.
BV1, BV2 - Blank check voltage, blank check at all listed
voltages. 5V default if not listed.
I would be happier knowing that I could margin test parts.
And I am looking forwards to the logic proramming option being enabled.
Thanks for a great product!
Martin |
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| Reply #1
ZLM
2945 Posts |
Posted - 12/15/2006 : 17:41:48
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The tWc and tWp params are controlled by Speed internally. That because most of user has difficulty to understand those parameters.
The software is able to set verify and blank check voltage independently.
The Vcc voltage can be selected from 3.6V, 5V, 5.5V, 6.2V.
The setting is done by change the device definition in file "devices.txt" . (BVCC="Blank Vcc",VCC="Read/Verify Vcc")
Please refer to the Help of software on "Add a new device to list" section.
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| Reply #2
martin
USA
6 Posts |
Posted - 12/15/2006 : 20:43:24
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| Thanks - that is helpful. It would be nice to know what twp the speed setting set. It would also be useful to be able to set two Vpp voltages for verify by putting two values after Vpp. It would be nice to have a 4.75V option, but I guess that is hard wired. |
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True USB notes - and feature request
