C509-L_97 Datasheet, PDF (26/290 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

Memory Organization
C509-L
3 Memory Organization
The C509-L CPU manipulates data and operands in the following five address spaces:
– up to 64 Kbyte of external program memory
– up to 64 Kbyte of external data memory
– 512 byte of internal Boot ROM (program memory)
– 256 bytes of internal data memory
– 3 Kbyte of internal XRAM data memory
– a 128 byte special function register area
Figure 3-1 illustrates the memory address spaces of the C509-L.
Figure 3-1
C509-L Memory Map
The internal XRAM data memory overlaps with the external data memory in the address range from
F400H to FFFFH. In this address range, either external or internal data RAM can be used. If the
internal XRAM has been enabled, it only can be disabled by an active RESET or HWPD signal.
The internal Boot ROM also overlaps with the external code memory in the address range from
0000H to 01FFH. Depending on the selected operating mode (chipmode), either external code
memory or the internal Boot ROM is accessed in this address range.
Semiconductor Group
3-1
1997-10-01