Filter
Top Products
5-5
MEMORY PARTITIONS
5.2.1 External Memory
Several partitions in pages 00H and FFH and all of pages 01H–0EH are assigned to external
memory (see Table 5-1). Data can be stored in any part of this memory. Instructions can be stored
in any part of this memory in 1-Mbyte mode, but can be stored only in page FFH in 64-Kbyte
mode. “Memory Configuration Examples” on page 5-27 contains examples of memory configu-
rations in the two modes. Chapter 13, “Interfacing with External Memory,” describes the external
memory interface and shows additional examples of external memory configurations.
5.2.2 Program and Special-purpose Memory
Program memory and special-purpose memory occupy a 4-Kbyte memory partition from
FF2000–FF2FFFH. For the 80C196NP and 80C196NU, this partition resides in external memory
(external addresses F2000–F2FFFH). For the 83C196NP, this partition resides in on-chip ROM
in page FFH, and it can also be mapped to page 00H (see “Remapping Internal ROM (83C196NP
Only)” on page 5-22).
5.2.2.1 Program Memory in Page FFH
Three partitions in page FFH can be used for program memory:
• FF0100–FF1FFFH in external memory (external addresses F0100–F1FFFH)
• FF2080–FF2FFFH
— 80C196NP and 80C196NU: This partition is in external memory (external addresses
F2080–F2FFFH).
— 83C196NP: The REMAP bit (CCB1.2), the EA# input, and the type of instruction
(extended or nonextended) control access to this partition, as shown in Table 5-2.
• FF3000–FFFFFH in external memory (external addresses F3000–FFFFFH)
NOTE
We recommend that you write FFH (the opcode for the RST instruction) to
unused program memory locations. This causes a device reset if a program
unintentionally begins to execute in unused memory.
Table 5-2. Program Memory Access for the 83C196NP
REMAP
(CCB1.2)
EA# Pin Instruction Type Memory Location Accessed
X Asserted Extended or nonextended External memory, F2080–F2FFFH
0 Deasserted Extended or nonextended Internal ROM, FF2080–FF2FFFH
1 Deasserted
Extended Internal ROM, FF2080–FF2FFFH
Nonextended External memory, 02080–02FFFH