Address Valid Time When Using AUTOPTR1/2 for External Data Memory Access

Question: How can we address external memory when using the AUTPOPTR1 or AUTOPTR2 in FX2/FX2LP  8051?



When using the AUTPOPTR1 or AUTOPTR2 to address external memory, the address of AUTOPTR1 will only be active while either RD# or WR# are active. The address of AUTOPTR2 will be active throughout the cycle and meet the address valid  time which is based on the stretch value.  Scetion 9.3 and 9.4 of the latest  version of the datasheet provides  this information.