Article ID: 000075732 Content Type: Troubleshooting Last Reviewed: 09/11/2012

What happens to the MAX II input/output (I/O) pins during a Real-Time in-system programming (ISP) update?


Description During the actual Real-Time ISP update process in MAX® II devices, the I/O pins are operating and running with the current design, i.e. the design running before Real-Time ISP started. Once the Real-Time ISP update to the configuration flash is complete - you can choose one of three options:

  1. Wait until the next power cycle before the new design takes over operation.
  2. Force an immediate download to the SRAM with appropriate JTAG commands (handled by the Quartus® II software or JAM file).
  3. Use the I/O ISP clamp to set the I/O voltages during real time ISP.

If this 'forced' download is used, then the I/O pins will tri-state during the SRAM download period for the same amount of time as the tCONFIG instant-on specification.

Refer to Real-Time ISP and ISP Clamp for MAX II Devices (PDF)  for more information.



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