User`s guide

Internal RAM LZ87010 Advance User’s Guide
4-2 1/15/03
4.1.2 MOVX RAM (4,096 Bytes)
The 4,096 byte memory space is mapped to addresses 0x0000-0x0FFF and is accessed
by the MOVX instruction, which allows 16-bit addresses. The upper 4 bits of the MOVX
address are ignored. Any MOVX instruction will thus access the 4KB RAM. Like the 256-
byte memory, the 4,096 byte MOVX RAM is implemented in high-speed, single-cycle-
access memory.
In traditional 8051 terminology, this memory would be called ‘external data RAM,’ but it is
internal to the LZ87010.
4.1.3 Expansion
Data memory is not expandable. Additional data storage can be obtained by using code
memory, which can be accessed in software through the MOVC instruction. Code memory
can be expanded through the external memory interface.
Figure 4-1. Memory Map
LZ87010-84
SPECIAL
FUNCTION
REGISTERS
(SFRs)
128 BYTES
DIRECT
ADDRESSING
MODE
MOV A, T2CNTL
INC P0
ADD A, P2
DIRECT AND
INDIRECT
ADDRESSING MODES
MOV A, DATA
MOV @R1,A
INDIRECT
ADDRESSING
MODE
MOV A, @R0
MOV @R1,A
EXTERNAL
ADDRESSING
MODE
MOVX A, @R1
MOVX @R0,A
CODE MEMORY
ADDRESSING
MODE
MOVC A, (DPTR)
MOVC (DPTR++),A
ACCESSED VIA:
EXAMPLES:
0xFFFF
0x0FFF
0x00FF
0x007F
0x0000
SCRATCHPAD
RAM
128 BYTES
SCRATCHPAD
RAM
128 BYTES
MOVX RAM
4KB
CODE
MEMORY
(INTERNAL
FLASH or
EXTERNAL
CODE MEMORY)
64KB