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Honored Contributor
Honored ContributorCyclone III AS Configuration
Hello, I am having some problems getting AS configuration working with my Cyclone III FPGA. I am using an EPCS16 for the configuration chip and the C3 is a EP3C25F324C8N on a custom board. Th...
Altera_ForumHonored Contributor
Honored ContributorWell those signals look really bad. However, that may be due to two reasons:
1 - You are measuring at the JTAG header rather than at the FPGA or serial configuration device. Measuring in the middle of the trace will often give you garbage. 2 - The rise and fall times on your ASDO and nCSO signals are terrible. What kind of scope probes are you using? Any capacitance in the probe will affect what you see (sometimes dramatically). For what you're looking at, you really need a probe in <10pF range. How are your MSEL pins configured? Looking at the Cyclone III datasheet, I would use 0010 or 0011 (depending on your voltage) for slow configuration. Also, yes you do need to specify the configuration scheme in Quartus. This is found by clicking on the "Device Options" button on the device settings page. Jake
