Filter
Top Products
5-29
MEMORY PARTITIONS
5.6.2 Example 2: A 64-Kbyte System with Additional Data Storage
Figure 5-10 shows another system designed for operation in the 64-Kbyte mode. Code executes
from page FFH only. This system is the same as the example in “Example 1: Using the 64-Kbyte
Mode” on page 5-27, but with additional RAM. The 64-Kbyte RAM stores near data in page 00H.
The 128-Kbyte RAM stores far data in pages 01H and 02H. Table 5-13 lists the memory address-
es. (For memory map details, see Table 5-1 on page 5-4.)
80C196NP and 80C196NU: The flash memory, which implements page FFH, holds the special-
purpose memory (FF2000–FF207FH), code, and far constants.
83C196NP only: Locations FF2000–FF2FFFH, which store code and special-purpose memory,
are implemented by internal ROM. Data accesses to locations FF2000–FF2FFFH are directed to
the flash memory if EA# is low and to internal ROM if EA# is high. Locations FF2000–FF2FFFH
can be remapped to page 00H by setting the REMAP bit (CCB1.2). An access to the remapped
area, 002000–002FFFH, is directed to ROM if EA# is high and to external memory if EA# is low.
With remapping enabled (REMAP = 1) and EA# high, the far constants in the special-purpose
memory can be accessed as near constants in page 00H.
Figure 5-10. A 64-Kbyte System with Additional Data Storage
A2475-02
Flash
64Kx8
Code & Data
FF0000–
FFFFFFH
CE#
Page FFH
A15:0
D7:0
OE# WE#
RAM
64Kx8
Data
000000–
00FFFFH
CE#
Page 00H
A15:0
D7:0
OE# WE#
8XC196NP,
NU
A16:0
AD7:0
RD#
WR#
CS1#
CS0#
A15:0
AD7:0
A15:1
AD7:0
RAM
128Kx8
Data
010000–
02FFFFH
CE#
Pages 01-02H
A16:0
D7:0
OE#
A16:0
AD7:0
WE#
CS2#