6-2
MPC8240 Integrated Processor User’s Manual
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Data path buffering—72 bits (64-bit data and 8-bit parity)
— Reduces loading on the internal processor core bus
— Reduces loading of the drivers of the memory system
— Reduces signal trace delay known as time-of-flight (TOF)
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Parity—Supports normal parity and read-modify-write (RMW)
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Error checking and correction (ECC)—64-bit only
— DRAM ECC—Located in the central control unit (CCU)
— SDRAM ECC—Located in-line with the data path buffers
The MPC8240 is designed to control a 32- or 64-bit data path to main memory (SDRAM
or DRAM). The MPC8240 can be configured to check parity or ECC on memory reads.
Parity checking and generation can be enabled with 4 parity bits for a 32-bit data path or 8
parity bits for 64-bit data path. Concurrent ECC is only generated for 64-bit data path with
8 syndrome bits.
The MPC8240 supports SDRAM or DRAM bank sizes from 1 to 128 Mbytes and provides
bank start address and end address configuration registers. However the MPC8240 does not
support mixed SDRAM or DRAM configurations.
The MPC8240 can be configured so that appropriate row and column address multiplexing
occurs for each physical bank. Addresses (DRAM or SDRAM) and bank selects (SDRAM
only) are provided through a 14-bit interface for SDRAM and 13-bit interface for DRAM.
ROM/Flash systems are supported by up to 21 address bits, 2 bank selects, 1 write enable
and 1 output enable. Figure 6-1 is a block diagram of the memory interface.
Summary of Contents for MPC8240
Page 1: ...MPC8240UM D Rev 1 1 2001 MPC8240 Integrated Processor User s Manual ...
Page 38: ...xviii MPC8240 Integrated Processor User s Manual TABLES Table Number Title Page Number ...
Page 48: ...xlviii MPC8240 Integrated Processor User s Manual Acronyms and Abbreviations ...
Page 312: ...6 94 MPC8240 Integrated Processor User s Manual ROM Flash Interface Operation ...
Page 348: ...7 36 MPC8240 Integrated Processor User s Manual PCI Host and Agent Modes ...
Page 372: ...8 24 MPC8240 Integrated Processor User s Manual DMA Register Descriptions ...
Page 394: ...9 22 MPC8240 Integrated Processor User s Manual I2O Interface ...
Page 412: ...10 18 MPC8240 Integrated Processor User s Manual Programming Guidelines ...
Page 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Page 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Page 516: ...16 14 Watchpoint Trigger Applications ...
Page 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
Page 546: ...C 8 MPC8240 Integrated Processor User s Manual ...
Page 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...