Keil MCB517AC, Руководство пользователя

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30 Chapter 4. Programming
External memory layout in non-banked mode.
Code memory Xdata memory
00000H
Monitor EPROM
0FFFFH
0E800H
00000H
0FFFFH
0F800H
0F700H
On-chip XRAM
*3
CAN-contoller
User Chip select
0F600H
0E800H
unused
User Code Area
(v. Neumann
mapped)
User XDATA
Area
*1
(overlaps User
Code Area!)
0D300H 0D300H
Mon. Data
*2
Mon. Data
*2
*1
Since this XDATA area is ‘von-Neumann’ wired, write accesses also modify
the CODE space. Locate your XDATA segments after the end of your
program and constant segments!
*2
Monitor 51 typically requires 256 bytes of external memory (0E700h -
0E7FFh). Only when you enable ‘Record trace’ in the dScope ‘Commands’
pull down menu, 5 KB additional memory is required to hold the trace
information.
*3
The 2Kb on-chip XRAM is available only with an 80C517A from X:F800h-
FFFFh when the SFR-bit XMAP0 is cleared
External memory layout in banked mode.
When the banked memory mode is selected, three port pins (P6.5 - P6.7) are used
to select the current code bank. Although it is possible to access 8 banks with
three additional address lines, your application can only use the first 6 banks with
monitor 51. The other two banks are used to hold the common area and the user-
XDATA area.