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CHAPTER 4
4.1
MEMORY MAP OVERVIEW.......................................................................................... 4-1
4.2
MEMORY PARTITIONS ................................................................................................ 4-3
4.2.1
External Memory .......................................................................................................4-5
4.2.2
Program and Special-purpose Memory ....................................................................4-5
4.2.2.1
Program Memory in Page FFH ............................................................................4-5
4.2.2.2
Special-purpose Memory .....................................................................................4-6
4.2.2.3
Reserved Memory Locations ...............................................................................4-7
4.2.2.4
Interrupt and PTS Vectors ....................................................................................4-7
4.2.2.5
Security Key .........................................................................................................4-7
4.2.2.6
Chip Configuration Bytes .....................................................................................4-8
4.2.3
Special-function Registers (SFRs) ............................................................................4-8
4.2.3.1
Memory-mapped SFRs ........................................................................................4-8
4.2.3.2
Peripheral SFRs ...................................................................................................4-9
4.2.4
Internal RAM (Code RAM) ......................................................................................4-11
4.2.5
Register File ............................................................................................................4-12
4.2.5.1
General-purpose Register RAM .........................................................................4-13
4.2.5.2
Stack Pointer (SP) ..............................................................................................4-13
4.2.5.3
CPU Special-function Registers (SFRs) .............................................................4-14
4.3
WINDOWING............................................................................................................... 4-15
4.3.1
Selecting a Window ................................................................................................4-16
4.3.2
Addressing a Location Through a Window .............................................................4-17
4.3.2.1
32-byte Windowing Example ..............................................................................4-19
4.3.2.2
64-byte Windowing Example ..............................................................................4-19
4.3.2.3
128-byte Windowing Example ............................................................................4-19
4.3.2.4
Unsupported Locations Windowing Example .....................................................4-20
4.3.2.5
Using the Linker Locator to Set Up a Window ....................................................4-20
4.3.3
Windowing and Addressing Modes .........................................................................4-22
4.4
REMAPPING INTERNAL OTPROM (87C196NT ONLY) ............................................ 4-23
4.5
FETCHING CODE AND DATA IN THE 1-MBYTE AND 64-KBYTE MODES.............. 4-24
4.5.1
Fetching Instructions ...............................................................................................4-24
4.5.2
Accessing Data .......................................................................................................4-24
4.5.2.1
Using Extended Instructions ..............................................................................4-25
4.5.3
Code Fetches in the 1-Mbyte Mode ........................................................................4-26
4.5.4
Code Fetches in the 64-Kbyte Mode ......................................................................4-26
4.5.5
Data Fetches in the 1-Mbyte and 64-Kbyte Modes .................................................4-27
4.6
MEMORY CONFIGURATION EXAMPLES ................................................................. 4-28
4.6.1
Example 1: A 64-Kbyte Mode 87C196NT System ..................................................4-28
4.6.2
Example 2: A 64-Kbyte 87C196NT System with Additional Data Storage ..............4-30
4.6.3
Example 3: A 1-Mbyte 87C196NT System with a 16-bit Bus ..................................4-32
4.6.4
Example 4: A 1-Mbyte 8XC196NT System with an 8-bit Bus .................................4-34
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