MOTOROLA
Chapter 16. Memory Controller
16-59
Part IV. Hardware Interface
in these examples apply to any UPM. UPMA is used in the page mode example and UPMB
is used in the extended data out example.
16.9.1 Page-Mode DRAM Interface Example
Figure 16-53 shows conÞguration for a 1-Mbyte, 32-bit wide memory system using four
256 Kbyte x 8-bit DRAMs. Also shown is the physical connection between UPMA and the
page mode DRAM. CS1 is connected to all RAS and is controlled by the base register.
BS_A[0Ð3] are mapped one-to-one to each of the four DRAMs and are controlled by the
UPM RAM word. The refresh rate is calculated based on a 25-MHz baud rate generator
clock and the DRAM that requires a 512-cycle refresh every 8 ms.
Figure 16-53. Page-Mode DRAM Interface Connection
Follow these steps to conÞgure a system for page mode DRAM:
1. Determine the system architecture, which includes the MPC860 and the memory
system as shown in the example in Figure 16-53.
2. Use the blank work sheet in Figure 16-70 to draw the timing diagrams for all the
memory cycles. The timing diagrams in Figure 16-54 through Figure 16-62 can be
used as a reference. Alternately, use the UPM860 or MCU unit applications for this.
These applications are available at http:/www.mot.com/netcomm/
3. Translate the timing diagrams into RAM words for each type of memory access. The
bottom half of the Þgures represent the RAM array contents that handle each of the
possible cycles and each column represents a different word in the RAM array. A
blank cell in the Þgures indicates a donÕt care bit, which is typically programmed to
logic 1 to conserve power.
RAS
CAS
W
A[0Ð8]
MCM84256
256K x 8
D[0Ð31]
A[21Ð29]
R/W
CS1
BS_A[0Ð3]
RAS
CAS
W
A[0Ð8]
MCM84256
256K x 8
BS_A2
RAS
CAS
W
A[0Ð8]
MCM84256
256K x 8
RAS
CAS
W
A[0Ð8]
MCM84256
256K x 8
BS_A0
BS_A1
BS_A3
D[0Ð7]
D[0Ð7]
D[0Ð7]
D[0Ð7]
8-Bit
8-Bit
8-Bit
8-Bit
D[16Ð23]
D[24Ð31]
D[0Ð7]
D[8Ð15]
MPC860
Summary of Contents for MPC860 PowerQUICC
Page 3: ...MPC860UM AD 07 98 REV 1 MPC860 PowerQUICC ª UserÕs Manual ...
Page 36: ...xxxvi MPC860 PowerQUICC UserÕs Manual MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Page 78: ...I iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 88: ...1 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 114: ...3 16 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 226: ...8 32 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Page 262: ...9 36 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Page 274: ...III iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Page 320: ...12 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Page 325: ...MOTOROLA Part IV Hardware Interface IV v Part IV Hardware Interface ...
Page 326: ...IV vi MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
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Page 632: ...21 44 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 660: ...22 28 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
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Page 998: ...37 48 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part VI Debug and Test ...
Page 1016: ...A 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1024: ...B 8 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1030: ...C 6 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
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