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Altera_Forum
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14 years ago

Can Cyclone IV JTAG VCC use separate 2.5V instead of VCCA?

The Cyclone IV handbook in section 8-47 says: --- Quote Start --- For device using VCCIO of 2.5, 3.0, and 3.3 V, refer to Figure 8–23. All I/O inputs must maintain a maximum AC volt...
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Altera_Forum
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14 years ago

--- Quote Start ---

what can cause voltage overshot in the USB Blaster if it's properly made by Altera?

--- Quote End ---

Good question. In fact, a PCB trace of some length or an IDC cable can be sufficient, due to the low driver impedance of some USB Blaster versions.

The below documented waveform has been acquired with an Altera Cyclone II evaluation board near the FPGA, using a Rev. B USB Blaster.