UPSD33XX Datasheet, PDF (142/231 Pages) STMicroelectronics – Fast 8032 MCU with Programmable Logic

uPSD33xx
Figure 58 illustrates the priority scheme of the
memory elements of the PSD Module. Priority re-
fers to which memory will ultimately produce a
byte of data or code to the 8032 MCU for a given
bus cycle. Any memory on a higher level can over-
lap and has priority over any memory on a lower
level. Memories on the same level must not over-
lap.
Example: FS0 is valid when the 8032 produces an
address in the range of 8000h to BFFFh.
CSBOOT0 is valid from 8000h to 9FFFh. RS0 is
valid from 8000h to 87FFh. Any address from the
8032 in the range of RS0 always accesses the
SRAM. Any address in the range of CSBOOT0
greater than 87FFh (and less than 9FFFh) auto-
matically addresses Secondary Flash memory.
Any address greater than 9FFFh accesses Main
Flash memory. One-half of the Main Flash memo-
ry segment, and one-fourth of the Secondary
Flash memory segment cannot be accessed by
the 8032 in this example.
Figure 58. PSD Module Memory Priority
Highest Priority
Level 1
SRAM,
CSIOP, and
Peripheral I/O
Mode
Level 2
Secondary
Flash Memory
Level 3
Main Flash Memory
Lowest Priority
AI02867E
The VM Register. One of the csiop registers (the
VM Register) controls whether or not the 8032 bus
control signals RD, WR, and PSEN are routed to
the Main Flash memory, the Secondary Flash
memory, or the SRAM. Routing of these signals to
these PSM Module memories determines if mem-
ories reside in 8032 program address space, 8032
XDATA space, or both. The initial setting of the VM
Register is determined by a choice in PSDsoft Ex-
press and programmed into the uPSD33xx in a
non-volatile fashion using JTAG. This initial setting
is loaded into the VM Register upon power-up and
also loaded upon any reset event. However, the
8032 may override the initial VM Register setting
at run-time by writing to the VM Register, which is
useful for IAP.
Table 78., page 143 defines bit functions within
the VM Register.
Note: Bit 7, PIO_EN, is not related to the memory
manipulation functions of Bits 0, 1, 2, 3, and 4.
Also note that SRAM must at least always be in
8032 XDATA space (default condition). Bit 0 al-
lows the user to optionally place SRAM into 8032
program space in addition to XDATA space.
CSIOP registers are always in XDATA space and
cannot reside in program space.
Figure 59., page 144 illustrates how the VM Reg-
ister affects the routing of RD, WR, and PSEN to
the memories on the PSD Module. As an example,
if we apply the value 0Ch to the VM Register to im-
plement the memory map example shown in Fig-
ure 53., page 138, then the routing of RD, WR,
and PSEN would look like that shown in Figure
60., page 145.
In this example, the configuration is specified in
PSDsoft Express and programmed into the
uPSD33xx using JTAG. Upon power-on or any re-
set condition, the non-volatile value 0Ch is loaded
into the VM Register. At runtime, the value 0Ch in
the VM Register may be changed (overridden) by
the 8032 if desired to implement IAP or other func-
tions.
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