Memory Controller
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 11-5
Figure 11-2. Memory Controller Machine Selection
Some features are common to all machines.
A 17-bit most-significant address decode on each memory bank
The block size of each memory bank can vary between 32 Kbytes (1 Mbyte for SDRAM) and 4
Gbytes (128 Mbytes for SDRAM).
Normal parity may be generated and checked for any memory bank.
Read-modify-write parity may be generated and checked for any memory bank with either 32- or
64-bit port size. Using RMW parity on 32-bit port size bank, requires the bus to be in strict 60x
mode (BCR[ETM] = 0. See Section4.3.2.1, “Bus Configuration Register (BCR).”
ECC may be generated and checked for any memory bank with a 64-bit port size
Each memory bank can be selected for read-only or read/write operation.
Each memory bank can use data pipelining, which reduces the required data setup time for
synchronous devices.
Each memory bank can be controlled by an external memory controller or bus slave.
The memory controller functionality minimizes the need for glue logic in PowerQUICCII-based systems.
In Figure 11-3, CS0 is used with the 16-bit boot EPROM with BR0[MS] defaulting to select the GPCM.
CS1 is used as the RAS signal for 64-bit DRAM with BR1[MS] configured to select UPMA. BS[0–7] are
used as CAS signals on the DRAM.
User-Programmable
Local General-Purpose
Bank 0
Bank 1
Bank 2
Bank 3
Bank 10
Bank11
MS
MS
MS
MS
MS
MS Chip-Select Machine
Local SDRAM Local
60x
Local
M
x
MR[BS]
60x SDRAM 60x
Local
60x General-Purpose
Chip-Select Machine 60x
Machine (A/B/C)
Machine
Machine