MOTOROLA
Chapter 10. Memory Controller
10-77
Part III. The Hardware Interface
Figure 10-79 shows an example of REDO use.
10.6.4.2 Address Multiplexing
The address lines can be controlled by the pattern the user provides in the UPM.
The
address multiplex bits can choose between outputting an address requested by the internal
master as is and outputting it according to the multiplexing speciÞed by the M
x
MR[AM
x
].
The last option is to output the contents of the MAR on the
address pins.
Note that in 60x-compatible mode, MAR cannot be output on the 60x bus external address
line.
Note that on the local bus, only the lower 18 bits of the MAR are output.
Table 10-37 shows how M
x
MR[AM
x
] settings affect address multiplexing.
See Section 10.6.5, ÒUPM DRAM ConÞguration Example,Ó for more details.
10.6.4.3 Data Valid and Data Sample Control
When a read access is handled by the UPM and the UTA bit is 1, the value of the DLT3 bit
in the same RAM word indicates when the data input is sampled by the internal bus master,
assuming that M
x
MR[GPL
x
4DIS] = 1.
¥
If G4T4/DLT3 functions as DLT3 and DLT3 = 1 in the RAM word, data is latched
on the falling edge of CLKIN instead of the rising edge. The data is sampled by the
internal master on the next rising edge as is required by the MPC8260 bus operation
spec. This feature lets the user speed up the memory interface by latching data 1/2
clock early, which can be useful during burst reads. This feature should be used only
in systems without external synchronous bus devices.
¥
If G4T4/DLT3 functions as G4T4, data is latched on the rising edge of CLKIN, as
is normal in MPC8260 bus operation.
Figure 10-65 shows data sampling that is controlled by the UPM.
Table 10-37. UPM Address Multiplexing
AM
x
External Bus
Address Pin
A16
A17 A18 A19 A20 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
000
Signal Driven
on External
Pin when
Address
Multiplexing
is Enabled
A8
A9
A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21 A22 A23
001
A7
A8
A9
A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21 A22
010
A6
A7
A8
A9
A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21
011
A5
A6
A7
A8
A9
A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20
100
Ñ
A5
A6
A7
A8
A9
A10 A11 A12 A13 A14 A15 A16 A17 A18 A19
101
Ñ
Ñ
A5
A6
A7
A8
A9
A10 A11 A12 A13 A14 A15 A16 A17 A18
Summary of Contents for MPC8260 PowerQUICC II
Page 1: ...MPC8260UM D 4 1999 Rev 0 MPC8260 PowerQUICC II UserÕs Manual ª ª ...
Page 66: ...lxvi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA ...
Page 88: ...1 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 120: ...2 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 138: ...Part II iv MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II Configuration and Reset ...
Page 184: ...4 46 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II ConÞguration and Reset ...
Page 202: ...Part III vi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 266: ...8 34 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 382: ...10 106 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 392: ...11 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 430: ...Part IV viii MOTOROLA Part IV Communications Processor Module ...
Page 490: ...14 36 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 524: ...17 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 556: ...18 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
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Page 980: ...A 4 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Appendixes ...
Page 1002: ...Index 22 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA INDEX ...
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