AN1176 STMicroelectronics, AN1176 Datasheet - Page 19

• Manufacturer Part Number: AN1176
• Description: 68HC11/PSD813F1 DESIGN GUIDE
• Manufacturer: STMicroelectronics

most use out of the 64K byte address space that the 68HC11 can access directly. This means
swapping the ISP loader code out of the memory map after ISP is complete, and replacing it with
application code, leaving the maximum amount of address space available for the application.
Swapping the ISP loader code not only frees up address space for application code, it also allows
the software designer the option of having two sets of interrupt vectors and associated service
routines; one set during ISP, and a different set during the normal application. In addition, this
swapping technique allows the ISP loader code itself to be downloaded in the field if necessary
while the 68HC11 operates out of main flash memory.
3.1 Physical Connections
Same as the simple design example (section 2.1).
3.2 Memory Map
The memory map has two basic configurations, boot-up/ISP and normal application. See Figures
5 and 6.
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