Motorola PowerQUICC II MPC8280 Series Reference Manual page 478

SDRAM Machine
11.4.5.2 SDRAM Address Multiplexing (SDAM and BSMA)
In single MPC8280 mode, the lower bits of the address bus are connected to the device's
address port, and the memory controller multiplex the row/column and the internal banks
select lines, according to the PL/SDMR[SDAM] and PL/SDMR[BSMA].
Table 11-20. shows how P/LSDMR[SDAM] settings affect address multiplexing. For the
effect of PL/SDMR[BSMA] see Section 11.4.12, "SDRAM Configuration Examples."
Note that in 60x-compatible mode, the 60x address must be latched and multiplexed by glue
logic that is controlled by ALE and SDAMUX, however, the user still has to configure
PSDMR[SDAM].
On the local bus, only the lower 18 bits of the address are output. Table 11-20 shows
SDRAM address multiplexing for A0–A15.
Table 11-20. SDRAM Address Multiplexing (A0–A15)
External Bus
SDAM A0
Address Pins
000 —
Signal driven
001 —
on external
010 —
pins when
address
011 —
multiplexing
100 —
is enabled
101 —
Table 11-21 shows SDRAM address multiplexing for A16–A31.
Table 11-21. SDRAM Address Multiplexing (A16–A31)
External Bus
SDAM A16 A17 A18 A19 A20 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Address Pins
000 A8
Signal driven
001 A7
on external
010 A6
pins when
address
011 A5
multiplexing
100 is enabled A4
101 —
11.4.6 SDRAM Device-Specific Parameters
The software is responsible for setting correct values to some device-specific parameter
that can be extracted from the data sheet. The values are stored in the ORx and P/LSDMR
registers. These parameters include the following:
11-40
Freescale Semiconductor, Inc.
A1 A2 A3 A4 A5
— — — — —
— — — — —
— — — — —
— — — — —
— — — — —
— — — — —
A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21 A22 A23
A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21 A22
A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21
A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20
A5 A6 A7 A8 A9
— A5 A6 A7 A8
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A6 A7 A8 A9 A10 A11 A12 A13 A14 A15
— — — — —
— — — — —
— — — — —
— — — — —
— — — — —
— — — — —
A10 A11 A12 A13 A14 A15 A16 A17 A18 A19
A9 A10 A11 A12 A13 A14 A15 A16 A17 A18
— — A5 A6 A7
— — — A5 A6
— — — — A5
— — — — —
— — — — —
— — — — —
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