AT89C5115
Figure 10. Lower 128 Bytes Internal RAM Organization
7Fh
30h
2Fh
bit-Addressable Space
(bit Addresses 0-7Fh)
20h
18h
10h
08h
00h
1Fh
17h
0Fh
07h
4 Banks of
8 Registers
R0-R7
Upper 128 Bytes RAM
Expanded RAM
The upper 128 Bytes of RAM are accessible from address 80h to FFh using only indirect
addressing mode.
The on-chip 256 Bytes of expanded RAM (XRAM) are accessible from address 0000h to
00FFh using indirect addressing mode through MOVX instructions. In this address
range.
Note:
Lower 128 Bytes RAM, Upper 128 Bytes RAM, and expanded RAM are made of volatile
memory cells. This means that the RAM content is indeterminate after power-up and
must then be initialized properly.
25
4128F–8051–05/06
ATMEL [ ATMEL ]
