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Altera_Forum
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11 years ago

EP3C16E144 JTAG and AS problem!

The JTAG chain can't be find, but the AS configuration is successful, why? MSEL1 is connected to 2.5V directly, MSEL0 and MSEL2 to GND. nCE is connected to GND directly. TCK is pull down wi...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

I pulled down the nCE pin with 10k resister to ground, i think this is right at AS mode.

I re- solder a new EP3C16E144 to this board, but the JTAG mode can not work as before.

Then, I solder another board without this power circuit, but make 1.2V, 2.5V and 3.3V power supply from other systems, ok, the AS and JTAG mode work well.

I think the power circuit problem is that the LT1076 to LT1959 has generate some noise, it can destroy partial function of the FPGA, the power scheme of this system must re- design now.