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Dear all,
This is my first attempt to create a FPGA board. My board only uses JTAG (no AS) for programming. I have attached the schematic and board in the *.zip file. Would you please having a look for me? I have some doubts 1/ Should I connect nCE of JTAG directly in to nCE of the FPGA, or nCE from FPGA is connected to ground? 2/ About the clock: I see that there are 16 clocks. To which clock I should connect the output from oscillator to? 3/ In my board, I only use 3.3V (the label VCC means 3.3V). Is that ok? Thank you for your help,Link Copied
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By the way, would you please showing me how to add a flashing LED to indicate the JTAG is working?
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nCE function is related to the AS/AP configuration interface. It's purpose is to tristate the FPGA signals driving a configuraton memory. It can be tied to GND if no external access to a configuration memory (through AS programming connector or embedded processor) is intended.
Your design is missing 1.2V and 2.5V supplies. Both are required by the Cyclone 3 FPGA, read the device manual. Furthermore bypass capacitors at all power supply pins are strongly suggested. I would always add a serial configuration flash (EPCS or compatible) to the design. It can be programmed through JTAG indirect method. A single clock input is sufficient for most basic designs.- Mark as New
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--- Quote Start --- nCE function is related to the AS/AP configuration interface. It's purpose is to tristate the FPGA signals driving a configuraton memory. It can be tied to GND if no external access to a configuration memory (through AS programming connector or embedded processor) is intended. Your design is missing 1.2V and 2.5V supplies. Both are required by the Cyclone 3 FPGA, read the device manual. Furthermore bypass capacitors at all power supply pins are strongly suggested. I would always add a serial configuration flash (EPCS or compatible) to the design. It can be programmed through JTAG indirect method. A single clock input is sufficient for most basic designs. --- Quote End --- Hi, thank you for your prompt response. I also just realized that I missed 1.2V and 2.5V. But the symbol confused me. I thought that all of the VCC pin of the symbol should be connected to 1.2V. Can you please show me which pins are 1.2V, which are 2.5 V according to the symbol? Also, is it ok if I only use JTAG without AS? Thanks

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