UPSD3422_06 Datasheet, PDF (19/293 Pages) STMicroelectronics – Turbo Plus Series Fast Turbo 8032 MCU with USB and Programmable Logic

uPSD34xx
4
Memory organization
Memory organization
Note:
The 8032 MCU core views memory on the MCU module as “internal” memory and it views
memory on the PSD module as “external” memory, see Figure 6
Internal memory on the MCU Module consists of DATA, IDATA, and SFRs. These standard
8032 memories reside in 384 bytes of SRAM located at a fixed address space starting at
address 0x0000.
External memory on the PSD Module consists of four types: main Flash (64K, 128K, or
256K bytes), a smaller secondary Flash (32K), SRAM (4K, 8K or 32Kbytes), and a block of
PSD Module control registers called csiop (256 bytes). These external memories reside at
programmable address ranges, specified using the software tool PSDsoft Express. See the
PSD Module section of this document for more details on these memories.
External memory is accessed by the 8032 in two separate 64K byte address spaces. One
address space is for program memory and the other address space is for data memory.
Program memory is accessed using the 8032 signal, PSEN. Data memory is accessed
using the 8032 signals, RD and WR. If the 8032 needs to access more than 64K bytes of
external program or data memory, it must use paging (or banking) techniques provided by
the Page Register in the PSD Module.
When referencing program and data memory spaces, it has nothing to do with 8032 internal
SRAM areas of DATA, IDATA, and SFR on the MCU Module. Program and data memory
spaces only relate to the external memories on the PSD Module.
External memory on the PSD Module can overlap the internal SRAM memory on the MCU
Module in the same physical address range (starting at 0x0000) without interference
because the 8032 core does not assert the RD or WR signals when accessing internal
SRAM.
Figure 6. uPSD34xx memories
Internal SRAM on
MCU Module
External Memory on
PSD Module
Fixed
Addresses
384 Bytes SRAM
FF Indirect
Addressing
128 Bytes
IDATA
SFR
80 ^{128 Bytes}
Direct
Addressing
7F
128 Bytes
DATA
0
Direct or Indirect Addressing
Main
Flash
64KB
or
128KB
or
256KB
• External memories may be placed at virtually
any address using software tool PSDsoft Express.
• The SRAM and Flash memories may be placed
in 8032 Program Space or Data Space using
PSDsoft Express.
• Any memory in 8032 Data Space is XDATA.
Secondary
Flash
SRAM
32KB
4KB
or
8KB
or
32KB
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