UPSD33XX Datasheet, PDF (141/231 Pages) STMicroelectronics – Fast 8032 MCU with Programmable Logic

uPSD33xx
– Figure 57. Place the larger Main Flash
Memory into XDATA space and the smaller
Secondary Flash into program space for
systems that need a large amount of Flash for
data recording or large look-up tables, and not
so much Flash for 8032 firmware.
Figure 57. Mapping: Small Code / Big Data
8032 PROGRAM
SPACE (PSEN)
FFFFh ^{Page X}
8032 XDATA SPACE
(RD and WR)
Page Page Page Page
0
1
2
3 _FFFFh
Nothing
Mapped
8000h
6000h
4000h
2000h
0000h
csboot3
8KB
csboot2
8KB
csboot1
8KB
csboot0
8KB
fs1 fs3 fs5 fs7
16KB 16KB 16KB 16KB
C000h
fs0 fs2
16KB 16KB
fs4
16KB
fs6
16KB
8000h
System I/O
2100h
csiop, 256 bytes,
Common to All Pages
2000h
rs0, 8KB
Common Memory to All Pages _0000h
AI09176
It is also possible to “reclassify” the Flash memo-
ries during runtime, moving the memories be-
tween XDATA memory space and program
memory space on-the-fly. This essentially means
that the user can override the initial setting during
run-time by writing to a csiop register (the VM Reg-
ister). This is useful for IAP, because standard
8051 architecture does not allow writing to pro-
gram space. For example, if the user wants to up-
date firmware in Main Flash memory that is
residing in program space, the user can temporari-
ly “reclassify” the Main Flash memory into XDATA
space to erase and rewrite it while executing IAP
code from the Secondary Flash memory in pro-
gram space. After the writing is complete, the Main
Flash can be “reclassified” back to program space,
then execution can continue from the new code in
Main Flash memory. The mapping example of Fig-
ure 57 will accommodate this operation.
Memory Sector Select Rules. When defining
sector select signals (FSx, CSBOOTx, RS0,
CSIOP, PSELx) in PSDsoft Express, keep these
rules in mind:
– Main Flash and Secondary Flash memory
sector select signals may not be larger than
their physical sector size as defined in Table
75., page 135.
– Any Main Flash memory sector select may not
be mapped in the same address range as
another Main Flash sector select (cannot
overlap segments of Main Flash on top of
each other).
– Any Secondary Flash memory sector select
may not be mapped in the same address
range as another Secondary Flash sector
select (cannot overlap segments of
Secondary Flash on top of each other).
– A Secondary Flash memory sector may
overlap a Main Flash memory sector. In the
case of overlap, priority is given to the
Secondary Flash memory sector.
– SRAM, CSIOP, or PSELx may overlap any
Flash memory sector. In the case of overlap,
priority is given to SRAM, CSIOP, or PSELx.
Note: PSELx is for optional Peripheral I/O
Mode on Port A.
– The address range for sector selects for
SRAM, PSELx, and CSIOP must not overlap
each other as they have the same priority,
causing contention if overlapped.
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