NXP Semiconductors MPC5644A, Reference Manual, Page: 293 / 1735

External Bus Interface (EBI)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 293
14.4.1.5 EBI Option Registers (EBI_OR0-EBI_OR3, EBI_CAL_OR0-3)
The EBI Option Registers are used to define the address mask and other attributes for the corresponding
chip select.
Figure 14-6. EBI Option Registers (EBI_OR0-EBI_OR3, EBI_CAL_OR0-3)
E0x14, E0x1C, E0x24, E0x2C,
E0x44, E0x4C, E0x54, E0x5C
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
R AM
W
RESET:
1
1
Some upper bits of the AM field may be tied to a fixed value, in which case the reset value is this fixed value and not zero.
Refer to
Section 14.1, Information Specific to This Device , to see which bits this applies to, if any.
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
R AM 0 0 0 0 0 0 0 SCY 0 BSCY 0
W
RESET: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
= Unimplemented or Reserved
Table 14-9. EBI Option Registers (EBI_OR0-EBI_OR3, EBI_CAL_OR0-3) Field Descriptions
Name Description
0-16
AM
AM — Address Mask
This field allows masking of any corresponding bits in the associated Base Register. Masking the
address independently allows external devices of different size address ranges to be used. Any
clear bit masks the corresponding address bit. Any set bit causes the corresponding address bit to
be used in comparison with the address pins. Address mask bits can be set or cleared in any order
in the field, allowing a resource to reside in more than one area of the address map. This field can
be read or written at any time.
Note: An MCU may have some of the upper bits of the AM field tied to a fixed value internally in
order to restrict the address range of the EBI for that MCU. See the corresponding Note for
the Base Register BA field for more details. Refer to the device-specific documentation to see
which bits are tied off, if any, for a particular MCU. Tied-off bits can be read but not written.