SAB80515 Datasheet, PDF (20/270 Pages) Siemens Semiconductor Group – 8-Bit Single-Chip Microcontroller Family

Memory Organization
Address Space
Lower 128 bytes of RAM
Upper 128 bytes of RAM
Special function registers
Locations
00H to 7FH
80H to 0FFH
80H to 0FFH
For details about the addressing modes see chapter 9.1.
Addressing Mode
direct/indirect
indirect
direct
Figure 4-1
Program Memory Address Space
The lower 128 bytes of the internal RAM are again grouped in three address spaces
(see figure 4-3):
1) A general purpose register area occupies locations 0 through 1FH (see also section 4.3).
2) The next 16 bytes, location 20H through 2FH, contain 128 directly addressable bits.
Programming information: These bits can be referred to in two ways, both of which are
acceptable for the ASM51. One way is to refer to their bit addresses, i.e. 0 to 7FH. The other
way is by referencing to bytes 20H to 2FH. Thus bits 0 to 7 can also be referred to as bits 20.0
to 20.7, and bits 08H and 0FH are the same as 21.0 to 21.7 and so on. Each of the 16 bytes in
this segment may also be addressed as a byte.)
3) Locations 30H to 7FH can be used as a scratch pad area.
Semiconductor Group
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