C509-L_97 Datasheet, PDF (29/290 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

Memory Organization
C509-L
3.4.1 Interface of External FLASH/ROM/EPROM and External SRAM Memory
The external FLASH/ROM/EPROM memory and the external SRAM memory can be used in the
chipmodes either as code memory or as data memory. The basic memory configuration is shown
in figure 3-2.
The following alternate function pins control the read/write accesses for code/data memories:
PSEN / RDF
P6.3 / WRF
P3.6 / WR
P3.7 / RD / PSENX
Read control signal for the FLASH/ROM/EPROM memory
Write control signal for the FLASH/ROM/EPROM memory
Write control signal for the SRAM memory
Read control signal for the SRAM memory
Figure 3-2
Interface of External FLASH/ROM/EPROM and External SRAM Memory
Semiconductor Group
3-4
1997-10-01