MPC555
/
MPC556
MEMORY CONTROLLER
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
10-27
10.8 Programming Model
The following registers are used to control the memory controller.
Note:
In all subsequent registers bit tables, if two reset values are given: the upper is for CSx, x = 1, 2, 3, and the lower
is dedicated to CS[0].
10.8.1 General Memory Controller Programming Notes
1. In the case of an external master that accesses an internal MPC555 / MPC556
module (in slave or peripheral mode), if that slave device address also matches
one of the memory controller’s regions, the memory controller will not issue any
CS for this access, nor will it terminate the cycle. Thus, this practice should be
avoided. Be aware also that any internal slave access prevents memory con-
troller operation.
2. If the memory controller serves an external master, then it can support access-
es to 32-bit port devices only. This is because the MPC555 / MPC556 external
bus interface cannot initiate extra cycles to complete an access to a smaller
port-size device as it does not own the external bus.
3. When the SETA bit in the base register is set, then the timing programming for
the various strobes (CS, OE and WE/BE) may become meaningless.
Table 10-5 Memory Controller Address Map
Address
Register
0x2F C100
Base Register Bank 0 (BR0)
0x2F C104
Option Register Bank 0 (OR0)
0x2F C108
Base Register Bank 1 (BR1)
0x2F C10C
Option Register Bank 1 (OR1)
0x2F C110
Base Register Bank 2 (BR2)
0x2F C114
Option Register Bank 2 (OR2)
0x2F C118
Base Register Bank 3 (BR3)
0x2F C11C
Option Register Bank 3 (OR3)
0x2F C120 —
0x13F
Reserved
0x2F C140
Dual-Mapping Base Register (DMBR)
0x2F C144
Dual-Mapping Option Register (DMOR)
0x2F C148 —
0x2F C174
Reserved
0x2F C178
Memory Status Register (MSTAT)
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Freescale Semiconductor, Inc.
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