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Altera_Forum
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11 years ago

Can't Access Jtag Chain, No device was deteced

I was maked a new pcb board depend on Cyclone V, but issue the problem as the title described. 1, The board's powers are ok, but i did not control the power-up sequence, and this could make t...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

1. You should look at the Power-Up Sequence section of the Power Management chapter of the cyclone v handbook (http://www.altera.com/literature/hb/cyclone-v/cyclone5_handbook.pdf). However, I would still expect the device to appear in the JTAG chain even if this power up sequence wasn't followed.

2. Check your schematic against Figure 7-17 in the same handbook (page 7-27). Do you see activity on all the JTAG signals? Do you see good signals on TMS, TCK & TDI - full voltage swing? Anything on TDO?

3. nCE, nSTATUS and CONF_DONE should be connected as per Figure 7-17.

4. CONF_DONE will remain low until the device is configured. If nCONFIG is high, nSTATUS should also be high. Do you have a pull-up on it?

Do you have a configuration device attached to your FPGA Some more info about your design might be helpful.

Cheers,

Alex