ST & T UPSD3212C - Manual (Page 104)

uPSD3212A, uPSD3212C, uPSD3212CV
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Separate Space Mode. Program space is sepa-
rated from Data space. For example, Program Se-
lect Enable (PSEN) is used to access the program
code from the primary Flash memory, while READ
Strobe (RD) is used to access data from the sec-
ondary Flash memory, SRAM and I/O Port blocks.
This configuration requires the VM Register to be
set to 0Ch (see Figure
51 ).
Combined Space Modes. The Program and
Data spaces are combined into one memory
space that allows the primary Flash memory, sec-
ondary Flash memory, and SRAM to be accessed
by either Program Select Enable (PSEN) or READ
Strobe (RD). For example, to configure the prima-
ry Flash memory in Combined space, Bits b2 and
b4 of the VM Register are set to '1' (see Figure
52 ).
Figure 51. Separate Space Mode
Figure 52. Combined Space Mode
Primary
Flash
Memory
DPLD Secondary
Flash
Memory
SRAM
RS0
CSBOOT0-1
FS0-FS3
CS CS CS
OE OE
RD
PSEN
OE
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Primary
Flash
Memory
DPLD Secondary
Flash
Memory
SRAM
RS0
CSBOOT0-1
FS0-FS3
RD
CS CS CS
RD
OE OE
VM REG BIT 2
PSEN
VM REG BIT 0
VM REG BIT 1
VM REG BIT 3
VM REG BIT 4
OE
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