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Altera_Forum
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14 years ago

Cyclone III configuration corrupts image

All, We have 30 boards with a single EP3c25 wired for JTAG and AS configuration, as per the handbook. Several pairs of eyes have peered at the schematic and the boards and everything looks like...
Altera_Forum's avatar
Altera_Forum
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13 years ago

I was just reading through this thread and wonder if you had the JTAG pull-ups and power on header pin 4 connected to 3.3V or 2.5V in your initial layout.

If so that's a possible issue. On Cyclone III the JTAG interface is based on VCCA which is 2.5V so that should the voltage connect to pin 4 of the header and used for the pull-ups on TDI and TMS.

I know we had issue with JTAG configuration when we had these connected to 3.3V on one of our boards.

See Figure 9-24 in the handbook. Note if the VCCIO is < 2.5V then these are connected to the VCCIO rail for the bank. as in figure 9-25