Aeroflex UT8MR8M8-EVB, User Manual, Page: 8 / 20

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5.4 Chip Enable
Asserting /E_All allows the device to be addressed as a single, 64Mb memory using address bits A21 and
A22 to decode and select 1 of 4 MRAM die.
Table 5. Enable Signals LEON-3FT (J5)
LEON-3FT connector
(J9)
UT8MR8M8 Device
(J7)
Pin
Signal Pin Signal
48 ROMSN0
21
Can be jumpered to /E_ALL for LEON-3FT to control the
UT8MR8M8
74
IOSN 21 Can be jumpered to /E_ALL
The user can exercise either the IOSN or ROMSN0 pin on the LEON-3FT to exercise the /E_All pin on the
MRAM. There is a three pin header, J5, that allows the user to select IOSN or ROMSN0 to control the
/E_All pin.
Figure 6. /E_All header control
5.4.1 Use as an External Memory with LEON
Set J5 to ROMSN0 on the UT8MR8M8-EVB and uninstall JP6 on the UT699-EVB.
5.4.2 Use as IO Space
Set J5 to IOSN option on the UT8MR8M8-EVB and install JP6 on the UT699-EVB.
5.5 Write Enable (/W)