AN1177 STMicroelectronics, AN1177 Datasheet - Page 6

• Manufacturer Part Number: AN1177
• Description: P51XA-PSD8XX DESIGN GUIDE
• Manufacturer: STMicroelectronics

AN1177 - APPLICATION NOTE
Figure 5. Memory Map, Simple P51XA/PSD813FX Design
Note the following about the sample memory map shown in Figure 5:
Note that placing the main Flash memory and secondary memory into Program Space or Data Space is
accomplished with the PSD VM Register. PSDsoft Express is used to define the initial value of the VM
Register when the system powers up or is reset. This initial value is stored in the fusemap that gets pro-
grammed into the PSD. At runtime, the VM register can be changed by writing to it with the MCU. This is
illustrated in the enhanced design of Section 4.
The boot memory holds the following information:
6/26
It is broken up into sixteen 64 KByte segments.
All areas, except the unmapped regions and the 80C51XA On-Chip RAM region, are resident on the
PSD.
It shows both Program Space and Data Space.
The 32 KBytes of the PSD813F boot memory is mapped to Program Space. There are several
references to “boot” memory in this document, but the “boot” memory is simply a secondary memory
that can be used as boot memory or can serve any other purpose.
The main Flash memory is mapped to Data Space so that the contents can be programmed.
The PSD Control Register and SRAM are in the bottom 64 KByte segment of Data Space.
P51XA reset vector and initialization routines
Not to
Scale
Here
Boot
from
F:FFFF
0:8000
0:6000
0:4000
0:2000
0:0000
2:FFFF
Optional Boot Flash/EEPROM (csboot3/ees3--8 Kbytes)
Optional Boot Flash/EEPROM (csboot2/ees2--8 Kbytes)
Optional Boot Flash/EEPROM (csboot1/ees1--8 Kbytes)
Optional Boot Flash/EEPROM (csboot0/ees0--8 Kbytes)
Program Space
13 x 64 KBytes
Unmapped
Unmapped
160 KBytes
Not to
Not to
Scale
Scale
2:C000
1:C000
F:FFFF
2:FFFF
2:8000
2:4000
2:0000
1:8000
1:4000
1:0000
0:1900
0:1000
0:1800
0:0000
PSD Control Register (CSIOP)
Main Flash Memory FS6
Main Flash Memory FS5
Main Flash Memory FS3
Main Flash Memory FS1
Main Flash Memory FS7
Main Flash Memory FS4
Main Flash Memory FS2
Main Flash Memory FS0
80C51XA On-Chip RAM
Optional SRAM (RS0)
256 Bytes to 1 KByte
16 KBytes FLASH
16 KBytes FLASH
16 KBytes FLASH
16 KBytes FLASH
16 KBytes FLASH
16 KBytes FLASH
16 KBytes FLASH
16 KBytes FLASH
3 to 3.75 KBytes
13 x 64 KBytes
Data Space
Unmapped
Unmapped
Unmapped
57.75 KBytes
256 Bytes
2 KBytes
AI03330B