UPSD3354DV-40U6 Datasheet, PDF (28/272 Pages) STMicroelectronics – fast 8032 MCU with programmable logic

Memory organization
4
Memory organization
UPSD33xx
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 5
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 (64, 128, or
256 Kbytes), a smaller secondary Flash (16 or 32 Kbytes), SRAM (2, 8, or 32 Kbytes), 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 Section 27: PSD module on page 164 of this document for more details on these
memories.
External memory is accessed by the 8032 in two separate 64 Kbyte address spaces. One
solete ^{Product(s) Note:}
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 64 Kbytes 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.
Ob _{Figure 5. UPSD33xx memories}
) ^- _{Internal SRAM on}
t(s ^{MCU Module}
External Memory on
PSD Module
roduc ^Fixed
Addresses
384 Bytes SRAM
P _{FF Indirect}
te Addressing
128 Bytes
ole^IDATA
bs₈₀ 128 Bytes
O 7F
SFR
Direct
Addressing
Main
Flash
64KB,
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
128 Bytes
DATA
16KB
or
32KB
2KB,
8KB,
or
32KB
CSIOP
256 Bytes
0
Direct or Indirect Addressing
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Doc ID 9685 Rev 7