About a err message in NiosII

The warning is put in place to advise you that the earlier download cables can be susceptible to noise. Errors from noise are likely to happen when the cable is continuously in use for a long period of time. Operations such as monitoring the JTAG UART using nios2-terminal or Nios II debug maintain JTAG connectivity for an extended period of time, as opposed to FPGA configuration, which lasts only a few seconds. Because of this new use-model of the JTAG cable, problems with noise (causing the Nios II I/O error you report) became more commonplace, especially for users in noisy environments or in close proximity to static electric discharge.

We have tried many experiments, from informal (BBQ igniters and power drills) to more official lab tests with some electrostatic discharge equipment that can be configured to generate pulses of varying strengths, durations, and frequencies to test the various download cables. As a result of this, the cable that ships with the Nios II Kit (the USB Blaster) was re-designed to be much more resilient to these sorts of external noise.

I cannot remember the specifics, but I believe Altera had a mail-in-replacement program in place for people who have purchased Nios kits and had problems with the cables due to noise. If this is the case, you may wish to contact Altera customer service to inquire about a replacement.

If you cannot or do not wish to replace the cable, there are some simple guidelines that can help with the problem:

- Move unshielded or poorly shielded electrical equipment away from the area where your Nios kit is used

- Consider moving your nios kit to a different location. For example, my cubicle at work is quite susceptible to noise problems when the (old) cables were left in use for over an hour or so; a co-worker 3-4 meters away experienced far less noise in his cubicle.

- Be careful to avoid electrostatic discharge; we have seen that certain combinations of clothing and furniture (!) would frequently produce static discharge "zaps" when the person moved or sat down -- which is of course never something you want around integrated circuits!