Hardware Description and Board Operation
3-20
M68VZ328ADS USER’S MANUAL
MOTOROLA
3.6.2 FLASH Memory
M68VZ328ADS is equipped with two 2M-byte Flash memory chips. Figure 3-2. shows the
interface of them. They are chip-selected by *CSA0 and *CSA1 signals. The connection of
these *CSAx signals to the Flash memories is controlled by DIP switches S2-1, S2-2 and
S2-3.
When S2-1 and S2-3 are close, *CSA0 connects Flash0 and *CSA1 connects Flash1.
Flash0 becomes the boot ROM. When S2-1 and S2-3 are open and S2-2 is close, *CSA0
connects Flash1 only. Flash1 will then be boot ROM instead. So, user can select either
FLASH0 or FLASH1 to be the boot ROM. These configuration allow users to put their appli-
cation program to boot ROM without having to erase the on-board monitor program.
Table 3-6 summaries the possible configuration of the S2-1, S2-2 and S2-3.
For more details on flash memory programming, please refer to Appendix B .
Table 3-6. Possible Configuration of FLASH Memories
S2-1
S2-2
S2-3
Boot ROM
Data ROM
ON
OFF
ON
FLASH0 (Monitor Program)
FLASH1
ON
OFF
OFF
FLASH0 (Monitor Program)
None
OFF
ON
OFF
FLASH1 (User Progam)
None
OFF
OFF
OFF
None
None
CSA0
OE
WE
1MX16-Bit FLASH
A[0..19]
D[0..15]
CE
OE
WE
1MX16-Bit FLASH
D[0..15]
A[1..20]
CSA1
MC68VZ328
CE
S2-1
S2-2
S2-3
VCC VCC
FLASH0
FLASH1
Figure 3-2. Interface of Flash Memories
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
nc.
..
