W925E240 Datasheet, PDF (10/73 Pages) Winbond – 8-BIT CID MICROCONTROLLER

W925E/C240
Data Memory
The W925E/C240 contains on-chip 8K MOVX RAM of Data Memory, which can only be accessed by
MOVX instructions from the address 0000H to 1FFFH. In addition, the W925E/C240 has 256 bytes of
on-chip scratchpad RAM. This can be accessed either by direct addressing or by indirect addressing.
There are also Special Function Registers (SFRs), which can only be accessed by direct addressing.
Since the scratchpad RAM is only 256 bytes, it can be used only when data contents are small. In the
event that larger data contents are present, the only one selection is on-chip MOVX RAM. The on-chip
MOVX RAM can only be accessed by a MOVX instruction. However, the on-chip RAM has the fastest
access times. The memory map is shown Figure 6-2 and Figure 6-3 shows the scratched-pad
RAM/register addressing.
FFH
80H
7FH
00H
Indirect
Addressing
RAM
Direct &
Indirect
Addressing
RAM
SFRs Direct
Addressing
only
1FFFH
8K byte SRAM On chip
0000H
Figure 6-2 memory map
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