As those who worked with with the HPPC 1500 or 1700 systems recall, the programming software and programming methodology are different for the HPPC compared with the PC700, 900, 1100 and 1200 processors.
Refer to http://www.pps2.com/communications/799.php (http://www.pps2.com/communications/799.php) and download the HPPC programming (APL or Advanced Program Loader) manual as well as the HPPC Systems Manual and the HPPC Systems Manual supplement for more information on those differences.