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:
- Wait until the next power cycle before the new design takes over operation.
- Force an immediate download to the SRAM with appropriate JTAG commands (handled by the Quartus® II software or JAM file).
- 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.