Chapter 6. MPC8240 Memory Interface
6-47
FPM or EDO DRAM Interface Operation
Some address and control signals may or may not require buffering, depending upon the
system design. Analysis of the MPC8240 AC specifications, desired memory operating
frequency, capacitive loads, and board routing loads assist the system designer in deciding
whether any signals require buffering. See the
MPC8240 Hardware Specifications
for more
information.
Figure 6-30. Example 16-Mbyte DRAM System with Parity—64-Bit Mode
CAS0
CAS1
CAS2
CAS3
RAS
WE
A[0:9]
DQ[0:35]
SIMM
RAS[2:7]
RAS[1]
RAS[0]
CAS[4]
WE
MPC8240
Buffers
4Mx36
SDMA[12:0]
PAR[0:7]
MDH[0:31]
Data path from
Address path to
Data[0:31]
Data[32:63]
Data[32:63]
Data[0:31]
MDL[0:31]
CAS[5]
CAS[6]
CAS[7]
NC
Parity[0:3]
Parity[4:7]
PAR[0:3]
PAR[4:7]
CAS[0]
CAS[1]
CAS[2]
CAS[3]
CAS0
CAS1
CAS2
CAS3
RAS
WE
A[0:9]
DQ[0:35]
SIMM
4Mx36
CAS0
CAS1
CAS2
CAS3
RAS
WE
A[0:9]
DQ[0:35]
SIMM
4Mx36
CAS0
CAS1
CAS2
CAS3
RAS
WE
A[0:9]
DQ[0:35]
SIMM
4Mx36
CAS[4:7]
CAS[0:3]
boot memory
boot memory
RAS[0]
RAS[1]
SDBA[1:0]
Buffers
Address
Signals
(Outputs)
SDMA
9
8
7
6
5
4
3
2
1
0
Logical Names
msb
MA
lsb
9
8
7
6
5
4
3
2
1
0
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 ...