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Altera_Forum's avatar
Altera_Forum
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16 years ago

Cannot detect device with own JTAG cable

Hello, I have just placed a MAXII on a custom board and am trying to program it with a ByteBlaster cable made following the usual schematics online. The programmer reports: Error: ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

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It seems to be getting 3.3v out of thin air for the power supply for the 74HC244 which is meant to be off the board (which wasnt connected)

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Not connecting VCCIO can be actually another reason, why the self elaborated "Byte Blaster" isn't working correctly. In my opinion, a HC244 isn't particularly suited for 5/3.3V level conversion. You should rather use a buffer, that allows to overdrive the inputs above the supply, e.g. VHC244. I've used a respective ByteBlaster replacement for years, see attachment, but I prefer USB Blaster performance.