Why does iMPACT erase a Platform Flash in a much shorter period of time than an SVF, XSVF, or ACE file?
iMPACT takes advantage of polling operations while erasing the PROM. iMPACT issues the erase command. The device starts erasing and when it is finished, a status bit is set denoting that the erase is complete. After iMPACT issues the erase command, the software starts checking this status bit. The status bit is continuously polled while the device is erasing. When the erase is complete, the software moves on to the next operation. Consequently, iMPACT can run this operation faster.
The SVF files do not have syntax for a looping function and the files must play straight through. Once the erase command is issued, the file must wait the maximum amount of time for the device to erase to ensure the erase is complete. This wait time in the SVF file is the maximum wait time required by the device at worst case temperature and voltage. Normal operating conditions allow an erase to run much faster.
The SVF files run slower than the software, however, since the SVF files cannot loop while the device is polled, there are no other options. This is a limitation of the SVF file syntax.