ST10R272L - MEMORY ORGANIZATION
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Most internal memory areas are mapped into segment 0, the system segment. The upper 4
KByte of segment 0 (00’F000h...00’FFFFh) hold the Internal RAM and Special Function
Register Areas (SFR and ESFR).
Code and data can be stored in any part of the internal memory areas, except for the SFR
blocks, which may be used for control / data, but not for instructions.
The ST10R272L is a ROMless device: program ROM must be in external memory.
Bytes are stored at even or odd byte addresses. Words are stored in ascending memory
locations with the low byte at an even byte address, followed by the high byte at the next odd
byte address. Double words (code only) are stored in ascending memory locations as two
subsequent words. Single bits are always stored in the specified bit position at a word
address. Bit position 0 is the least significant bit of the byte - at an even byte address, and bit
position 15 is the most significant bit of the byte - at the next odd byte address. Bit
addressing is supported for a part of the Special Function Registers, a part of the internal
RAM and for the General Purpose Registers.
Figure 5 Storage of words, bytes and bits in a byte organized memory
