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Altera_Forum
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10 years ago

Cyclone IV configuration - nCONFIG signal and JTAG programming issue

Hi, I have a custom board for EP4CE22E22 Cyclone IV FPGA. I have configured the board for JTAG only mode and using USB Blaster Rev.B for programming. The problem I am facing is that JTAG Scan f...
Altera_Forum's avatar
Altera_Forum
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10 years ago

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Signal integrity. I've had similar, intermittent issues before and it turned out to be a signal integrity issue between the USB-Blaster and the board. How are you programming the FPGA? Using a USB-Blaster or something else?

What revision is the USB-Blaster? The older units - rev A especially - have trouble with the newer FPGA families (I count Cyclone IV in that). Do you have particularly long JTAG traces on your PCB?

Cheers,

Alex

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I am using USB Blaster Rev.B. Traces on PCB are not long (< 1 cm) but the JTAG cable is ribbon type about 6 inches in length. Could that be an issue with new FPGAs?