The information in this publication is subje ct to change without no ti ce.
COMPAQ COMPUTER CORPORATION SHALL NOT BE LIABLE FOR TECHNICAL OR EDITORIAL
ERRORS OR OMISSIONS CONTAINED HEREIN, NOR FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING FROM THE FURNISHING, PERFORMANCE, OR USE OF THIS MATERIAL. THIS
INFORMATION IS PROVIDED "AS IS" AND COMPAQ COMPUTER CORPORATION DISCLAIMS ANY
WARRANTIES, EXPRESS, IMPLIED OR STATUTORY AND EXPRESSLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE, GOOD TITLE AND AGAINST
INFRINGEMENT.
This publication con ta ins information protecte d by copyright. No part of this publ i ca ti on m ay be photocopied or
reproduced in any form wit hout prior written consen t from Compaq Computer Corporation.
This manual describe s t he COMPAQ AlphaPC 264DP, including the mainboard and
the daughtercard, for computing systems based on COMPAQ’s Alpha 21264 microprocessor and the COMPAQ 21272 core logic chipset.
Audience
This manual is intended for system designers and others who use the AlphaPC
264DP to design or evaluate computer systems based on the Alpha 21264 microprocessor and the 21272 core logic chipset.
Scope
This manual describes the features, configuration, functional operation, and interfaces of the AlphaPC 264DP. This manual does not include specific bus specifications (for e xample, PCI or I SA buses). Add itional information is avai lable in the
AlphaPC 264DP schematics, program source files, and the appropriate vendor and
IEEE specifications. See Appendix A for information on how to order related documentation and obtain additional technical support.
Preface
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ix
Page 10
Manual Organization
This manual includes the following chapters, an appendix, and an index.
•Chapter 1, AlphaPC 264DP Introduc tion, is an overvi ew of the Alpha PC 264DP,
including its components, features, and uses.
•Chapter 2, System Configuration and Connectors, describes the user-environ-
ment configuration, boar d connectors and functions, and s witch functions. It also
identifies switch settings and connector locations.
•Chapter 3, Power and Environmental Requirements, describes the AlphaPC
264DP power and environmental requirements and provides board dimensions.
•Chapter 4, Functional Description, provides a functional description of the
AlphaPC 264DP mainboard, including the 21272 core logic chipset, L2 backup
cache (Bcache) and memory subsystems, system interrupts, clock and power
subsystems, and peripher al component interconnect (PCI) and In dustry Sta ndard
Architecture (ISA) devices.
•Chapter 5, System Memory a nd Addre ss Mapp ing, desc ribes how t o upgr ade t he
AlphaPC 264DP mainboard’s SDRAM memory.
•Appendix A, Support, Products, and Documentation, lists sources for compo-
nents and accessories not included with the AlphaPC 264DP, describes how to
obtain COMPAQ informat ion and techn ical support , and how to orde r COMPAQ
products and associated literature.
Conventions
This section defines product-specific terminology, abbreviations, and other conventions used throughout this manual.
Abbreviations
Register Access
•
The following list describes the register bit and field abbreviations:
Bit/Field AbbreviationDescription
RO (read only)Bits and fields specified as RO can be read but not written.
RW (read/write)Bits and fields specified as RW can be read and written.
WO (write only)Bits and fields specified as WO can be written but not read.
x
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Page 11
•Binary Multiples
The abbreviations K, M, and G (kil o, mega, and gi ga) re prese nt bina ry multi ples
and have the following values:
K
M
G
10
=2
20
=2
30
=2
(1024)
(1,048,576)
(1,073,741,824)
For example:
2KB=2 kilobytes
4MB=4 megabytes
8GB=8 gigabytes
Addresses
=2 × 2
=4 × 2
=8 × 2
10
bytes
20
bytes
30
bytes
Unless otherwise noted, all addresses and offsets are hexadecimal.
Bit Notation
Multiple-bit fields can include contiguous and noncontiguous bits contained in
brackets ([]). Multiple contiguous bits are indicated by a pair of numbers separated
by a colon (:). For example, [9:7,5,2:0] specifies bits 9,8,7,5,2,1, and 0. Similarly,
single bits are frequently indicated with brackets. For example, [27] specifies bit 27.
Caution
Cautions indicate potential damage to equipment, software, or data.
Data Field Size
The term INTnn, where nn is one of 2, 4, 8, 16, 32, or 64, refers to a data field of
nn contiguous NATURALLY ALIGNED bytes. For example, INT4 refers to a
NATURALLY ALIGNED longword.
Data Units
The following data-unit terminology is used throughout this manual.
Term WordsBytesBitsOther
Byte½18—
Word1216—
Longword/Dword2432Longword
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xi
Page 12
Term WordsBytesBitsOther
Quadword48642 L ongwords
Octaword8161282 Quadwords
Hexword16322562 Octa words
Note
Notes emphasize particularly important information.
Numbering
All numbers are decimal or hexadecimal unless otherwise indicated. The prefix 0x
indicates a hexadecimal number. For example, 19 is decimal, but 0x19 and 0x19A
are hexadecimal (also see Addresses). Otherwise, the base is indicated by a subscript; for example, 100
Ranges and Extents
is a binary number.
2
Ranges are specified by a pai r of nu mbers separ ated b y two per iods ( ..) and a re inc lusive. For example, a range of integers 0..4 includes the integers 0, 1, 2, 3, and 4.
Extents are specified by a pair of numbers in brackets ([]) separated by a colon (:)
and are inclusive. Bit fields are often specified as extents. For example, bits [7:3]
specifies bits 7, 6, 5, 4, and 3.
Register and Memory Figures
xii
Register figures have bit and field position numbering starting at the right (low
order) and increasing to the left (high order).
Memory figures have addresses starting at the top and increasing toward the bottom.
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Page 13
Signal Names
All signal names are printed in boldface type. Signal names that originate in an
industry-standard specification, such as PCI or IDE, are printed in the case as found
in the specification (usually uppercase). Active-high signals are indicated by the _h
suffix. Active-low signals have the _l suffix, a pound sign “#” appended, or a “not”
overscore bar. Signals with no suffix are consider ed high-asserted signals. Fo r exa m ple, signals data_h[127:0] and cia_int are active-high signals. Signals mem_ack_l, FRAME#, and RESET
UNPREDICTABLE and UNDEFINED
are active-low signals.
Throughout this manual the terms UNPREDICTABLE and UNDEFINED are used.
Their meanings are quite different and must be carefully distinguished.
In particular, only priv il eg e d sof tw are (th a t is , sof tw a re ru nn ing in ke rnel mod e )
can trigger UNDEFINED operations. Unprivileged software cannot trigger
UNDEFINED operations. However, either privileged or unprivi leged softwa re can
trigger UNPREDICTABLE results or occurrences.
UNPREDICTABLE results or occurrences do not disrupt the basic operation of the
processor. The processor continues to execute instructions in its normal manner. In
contrast, UNDEFINED operations can halt the processor or cause it to lose information.
The terms UNPREDICTABLE and UNDEFINED can be further described as follows:
•UNPREDICTABLE
–Results or occurrences specified as UNPREDICTABLE might vary from
moment to moment, impleme ntation to impleme ntation, and instru ction to
instruction withi n implement ations. Soft ware can never dep end on resul ts
specified as UNPREDICTABLE.
–An UNPREDICTABLE result might acquire an arbitrary value that is
subject to a few constraints. Such a result might be an arbitrary function
of the input operands or of any state information that is accessible to the
process in its current access mode. UNPREDICTABLE results may be
unchanged from their previous values.
Operations that produce UNPREDICTABLE results might also produce
exceptions.
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xiii
Page 14
–An occurrence specified as UNPREDICTABLE may or may not happen
based on an arbitrary choice function. The choice function is subject to
the same constraints as are UNPREDICTABLE results and must not constitute a security hole.
Specifically, UNPREDICTABLE results must not depend upon, or be a
function of, the co ntents of memo ry loca tions or r egist ers t hat ar e inac cessible to the current process in the current access mode.
Also, operations that migh t pr odu ce UNPREDI CTABLE results must not
write or modify the con tents of memor y locations or registers to which the
current process in the current access mode does not have access. They
must also not halt or hang the system or any of its components.
For example, a security hole would exist if some UNPREDICTABLE
result depended on the value of a register in another process, on the contents of processor te mp ora ry r eg is ter s l ef t behi nd by some previously running process, or on a sequence of actions of different processes.
•UNDEFINED
–Operati ons spe cifi ed as UNDEFINED can vary from moment to moment ,
implementation to implementation, and i nstruction to instruction w ithin
implementations. The operation can vary in effect from nothing, to stopping system operation.
xiv
–UNDEFINED operations can halt the processor or cause it to lose infor-
mation. However, UNDEFINED operations must not cause the processor
to hang, that is, reach an unhalted state from which there is no transition
to a normal state in which the machine executes instructions. Only privileged software (that is, software running in kernel mode) can trigger
UNDEFINED operations.
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Page 15
System Components and Features
AlphaPC 264DP Introduction
This chapter prov ides a n overv iew of the Alp haPC 2 64DP syst em, includi ng its c omponents, features, and uses.
The AlphaPC 264DP system consists of an AlphaPC 264DP mainboard (mainboard) and one or two AlphaPC 264DP daughtercards (daughtercards). The daughtercard consists of the 21264 microprocessor, L2 cache, reset field programmable
gate array (reset FPGA), and power converters for 2.2 volts and 1.5 volts.
1.1 System Components and Features
1
The AlphaPC 264DP is implemented in industry-standard parts and uses one or two
21264 CPUs running at 500 MHz. The functional components are shown in
Figure 1–1 and introduced in the following subsections.
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AlphaPC 264DP Introduction1–1
Page 16
System Components and Features
Figure 1–1 AlphaPC 264DP Functional Block Diagram
Daughtercard 1
L2 Cache
2/4MB
21264
CPU
Daughtercard 2
(Optional)
L2 Cache
2/4MB
21264
CPU
Sysdata
bus 0
Cmd/addr
bus 0
Cmd/addr
bus 1
Sysdata
bus 1
1.1.1 Memory Subsystem
The DRAM memory subsystem on the AlphaPC 264DP consists of sixteen 200-pin
buffered DIMM slots, which are organized as four arrays of memory. The 21272
core logic chipset (21272) supports two 256-bit memory buses (288-bit including
ECC) with two arrays on each bus.
Mainboard
memdata1
21272
Dchip
(8)
memdata0
Cchip
Flash
FPGA
ROM
capbus
TIGbus
Config
SDRAM
8 DIMMs
Main Memory
SDRAM
8 DIMMs
Pchip
(2)
IRQ
I
S
A
Southbridge
PCI1
PCI1 Slots (3)
ISA Slot (1)
Combination
Controller
Keyboard
Mouse
IDE
PCI0
COM1
COM2
Parallel Port
Floppy Diskette
Connector
PCI/SCSI
PCI0 Slots (3)
The 72-bit, 100-MHz DIMMs consist of 64 bits of data and 8 bits of ECC, and can
be 32MB, 64MB, 128MB, or 256MB. The minimum conf iguration (one array populated with four 32MB DIMMs) is 128MB. The maximum configuation (four arrays
each populated with four 256MB DIMMs) is 4GB.
The memory cycle time is 83 MHz, identical to the 21272 cycle time.
Note:Although the memory cycle time is 83 MHz, qualified 100-MHz
DIMMs are r equired.
1.1.2 21272 Core Logic Chipset
The 21264 is supported by the 21272, with a 256-bit memory interface. The 21272
consists of the following three chips:
1–2AlphaPC 264DP Introduction
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Page 17
•The Cchip provides the interface from the CPU and main memory, and includes
a general-purpose int erface for the fla sh ROM and interrupts (TI Gbus Interface).
One Cchip is used per system.
•The Dchip provides the data path from the CPU to memory and I/O. Two, four,
or eight Dchips can be used in a system configuration. Eight Dchips provide
two 256-bit memory bus interfaces on the AlphaPC 264DP.
•The Pchip provides a n i nt erf ace to the periphe ra l component interconne ct (PCI).
One or two Pchips can be used in a system configuration. Two Pchips can be
used to provide two independent 64-bit PCI buses. AlphaPC 264DP uses two
Pchips to support two 64-bit PCI buses running at 33 MHz.
The chipset includes the majority of functions required to develop a high-performance PC or workstation, requiring minimum discrete logic on the module. It provides flexible and generic functions to allow its use in a wide range of systems.
1.1.3 CPU Daughtercard
The 21264 microprocessor and level 2 cache reside on a separate daughtercard that
plugs into the mainboard. One or two daughtercards can be used in an AlphaPC
264DP system. The daughtercard is a 10-layer printed-circuit board with dimen-
sions of approximately 14 .99 cm × 30.48 cm (5.905 in × 12.0 in). The daughtercard
consists of the following :
System Components and Features
•21264 CPU
•Synchronous level 2 cache (2MB or 4MB cache, using late-write cache
SSRAMs)
•A linear regulator, providing 3.3 volts to 1.5 volts conversion for SSRAMs
•dc-to-dc converter for 5 volts to 2.2 volts for 21264 core power
•Reset and configuration FPGA
•Presence detect for cache configuration and CPU speed
•512KB flash ROM used as SROM
•SROM test port
•270-pin interface to mainboa rd (system clock forwarding interface and misc el la -
neous signals)
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AlphaPC 264DP Introduction1–3
Page 18
System Components and Features
1.1.3.1 Level 2 Cache Subsystem Overview
The external level 2 (L2) cache subsystem on the daughtercard supports 2MB or
4MB cache sizes using a 128-bit data bus.
The AlphaPC 264DP supports L2 cache using the synchronous SRAM (SSRAM)
sizes shown in Table 1–1. Nine SSRAMs are required per daught ercard f or 4MB L2
cache and five SSRAMs are re quired per daughtercard f or 2MB L2 c ache. In a dualprocessor system, cache sizes must be the same across the two daughtercards. The
first implementation of the daughtercard uses late-write SSRAMs.
Table 1–1 L2 Cache Size
L2 Cache SizeSRAM Type
2MBFour 128KB × 36 data SSRAMs and one 128KB × 36 tag SSRAM
4MBEight 256KB × 18 data SSRAMs and one 128KB × 36 tag SSRAM
1.1.3.2 21264 DC-to-DC Converter
The dc-to-dc converter is a 3.0 × 2.2 × 1.4-inch module that is mounted on the
daughtercard. It delivers 2.2 volts to the 21264. The features include:
•Programmable voltage between 1.5 volts and 2.5 volts
•Remote sense
•Overvoltage protection
•Current limit and short circuit protection
•Thermal shutdown
1.1.4 Clock Subsystem
The clock subsystem provides c locks t o the CPU, 2127 2, SDRAM DIMMs, and PCI
devices. A PC clock generator provides clocks for the SCSI, ISA, and combination
chip functions.
1–4AlphaPC 264DP Introduction
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Page 19
1.1.5 PCI Interface
The PCI interface provides a PCI speed of 33 MHz. The Cypress CY82C693UB
(southbridge) provides the following:
•PCI-to-ISA b ridge
•PCI to IDE in terface
•Real-time clock support
•Mouse and keyboard controller
The PCI to SCSI interface is derived from the Adaptec AIC7895 controller
(AIC7895). The AIC7895 supports two separated ultrawide SCSI ports.
The PCI has five dedicated 64-bit slots and one shared 64-bit slot. The one shared
slot also provides a 16-bit ISA expansion slot. Six expansion slots in total are sup-
ported—six PCI, or five PCI and one ISA.
The two PCI buses are configured as follows:
•PCI bus 0: contains Pchip0, southbridge, Adaptec SCSI, and three 64-bit expan-
sion slots
System Components and Features
•PCI bus 1: contains Pchip1 and three 64-bit expansion slots
1.1.6 ISA Interface
The ISA bus provides an expansion bus and the following system support functions:
•The ISA bus has one shared expansion slot with the PCI.
•An SMC FDC37C669 super I/O controller chip is used as the combination con-
troller chip that provides a diskette controller, two universal, asynchronous
receiver/transmitters (UARTs) for com ports, and a parallel port.
1.1.7 IDE Interface
The integrated drive electronics (IDE) provides an additional expansion bus, with
one connector on the mainboard.
Note:Only CD-ROMs with an IDE cable length of 12 inches or less are sup-
ported.
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AlphaPC 264DP Introduction1–5
Page 20
Page 21
System Configuration and Connectors
2.1 Board Layouts and Components
The AlphaPC 264DP uses switches to implement variations in clock frequency
(21272 and 21264) and L2 ca che configur ation. Note that the swi tches for the 21264
speed and L2 cache configuration are on the daughtercard. The switches for the
21272 speed are on the ma inboar d. These switch es must b e confi gured f or the user’s
environment. Onboard connectors are provided for the I/O, memory DIMMs, serial
and parallel peripherals, and IDE devices.
After the board is configured, you can apply power and start up the firmware that is
loaded in the flash ROM.
Figure 2–1 shows the AlphaPC 264DP mainboard and its components.
The Fail-Safe Booter (FSB) utility provides an emergency recovery mechanism
when the primary firmware image contained in flash memory has been corrupted.
When flash memory has been c orrupt ed, and no image can be loade d safel y from t he
flash ROM, you can run the FSB and boot another image from a diskette that is
capable of reprogramming the flash ROM.
2.2.2 Memory Timing
The memory bus timing is controlled by switches 2 and 3 of SW2 on the mainboard
(see Figure 2–3). Both switches are off by default, and they must be kept off.
2.2.3 Mini-Debugger
The Alpha SROM Mini-Debugger is stored in the flash ROM and is enabled/
disabled by switch 4 of SW2 on th e mainboar d (see Fi gure 2–3). The def ault posit ion
for this switch is of f. When this switch is on, it causes the SROM init ializatio n to trap
to the Mini-Debugger after all initialization is complete, but before starting the
execution of the system flash ROM code.
AlphaPC 264DP Mainboard Configuration Switches
2.2.4 Password Bypass
AlphaBIOS provides password protection. However, if the use of passwords has
been enabled and you have forgotten the current password, password bypass is provided through the use of switch 8 (pby) of SW2 on the mainboard.
Normal operation, with switch 8 in the off position (see Figure 2–3), requires a
password. The password bypass function is enabled by setting the switch to the on
position. This disables t he Alph aBIOS pas swor d ver if ic ati on and enables the user to
set up or start up their system without the AlphaBIOS password. Password bypass
also clears the password.
After this function has been enabled, to disable it and require a password, set switch
8 to the off position.
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System Configuration and Connectors2–7
Page 28
AlphaPC 264DP Daughtercard Configuration Switches
2.2.5 Flash Write Protection
The AlphaPC 264DP provides write protection for the firmware flash ROM. By
default, writing to the flash ROM is allowed, that is, switch 8 (flash_wr) of SW3 on
the mainboard is off (see Figure 2–4).
Note:The AlphaPC 264DP will not function if switch 8 is in the on position.
2.2.6 21272 Speed
The speed of the 21272 core logic chipset is determined by switches 5–7 of SW2.
The default positi ons are 5 and 6 on , 7 of f. These s witches mus t be kept in the de fault
position.
The AlphaPC 264DP daughtercard has one switchpack, located at SW2, as shown
previously in Fig ure 2–2. These switches set the hardware configurati on. Fi gur e 2 –5
shows these switch configurations.
Note:There is no switchpack SW1 on production daughtercards. Onboard
resistors set the configuration (cache size, CPU speed, and flash ROM
use) to the default state.
Figure 2–5 Daughtercard Configuration Switches
SW2
OffOn
vout_set0
vout_set1
vout_set2
vout_set3
flash_sel2
flash_sel1
flash_sel0
flash_sel_
2–8System Configuration and Connectors
bypass
1
2
3
4
5
6
7
8
Note: Switch defaults are in bold.
Set Output Voltage:
V dc3210
2.214 On Off On On
Flash ROM Select:
OffOff Of fOn
vout_set
x
flash_selxflash_sel_
210bypass
12 February 1999 – Subject To Change
Note:
All othe r comb inat ions are r eser ved.
Note:
All other combinations are reserved.
Page 29
AlphaPC 264DP Mainboard Connector Pinouts
2.4 AlphaPC 264DP Mainboard Connector Pinouts
This section lists the pinouts of the mainboard connectors (see Table 2–3 through
Ta ble 2–21). See Figure 2–1 for connector locations.
2.4.1 Daughtercard Connector Pinouts
Table 2–3 shows the daughtercard connector pinouts.
2.5.4 AlphaPC 264DP Daughtercard Input Power Connector Pinouts
Ta ble 2–25 shows the input power connector pinouts.
Table 2–25 Input Power Connector Pinouts (J4)
Pin VoltagePin VoltagePin VoltagePin Voltage
1+5 V dc2Gnd3+5 V dc4Gnd
5+5 V dc6Gnd7+5 V dc8Gnd
9+5 V dc10Gnd11+5 V dc12Gnd
13+5 V dc14Gnd15+5 V dc16Gnd
17+5 V dc18Gnd
2–24 System Configuration and Connectors
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Page 45
Power Requirements
Power and Environmental Requirements
This chapter describes the AlphaPC 264DP power and environmental requirements
and physical board parameters, for both the mainboard and the daughtercard.
3.1 Power Requirements
The mainboard has a maximum t otal power diss ipation of 215 W, excluding any disk
drives. Each daughtercard has a maximum total power dissipation of 129 W.
Table 3–1 lists the current requirement for each dc supply voltage.
Table 3–1 Power Supply DC Current Requirements
3
Voltage/ToleranceCurrent
Mainboard
+3.3 V dc, ±5%30.0 A
+5 V dc,
5 VSB dc,
+12 V dc,
–12 V dc,
Daughtercard
+3.3 V dc, ±5%5.0 A
+5 V dc,
+12 V dc,
–12 V dc,
12 February 1999 – Subject To Change
±5%20.0 A
±5%1.0 A
±5%0.8 A
±5%0.1 A
±5%22.0 A
±5%0.1 A
±5%0.05 A
Power and Environmental Requirements3–1
Page 46
Environmental Requirements
Caution:Fan sensor required. The 2126 4 microprocessor coolin g f an must have
a built-in sensor t hat will dr ive a sig nal if t he airflow st ops. The se nsor is
connected to power con nector J1. When the signal is generated, it resets
the system.
3.2 Environmental Requirements
The 21264 microprocessor is cooled by a small fan blowing directly into the chip’s
heat sink. The daughtercard is designed to run efficiently by using only this fan.
Additional fans may be nec essar y dependi ng upon c abinet ry and t he req uirement s of
plug-in cards.
The AlphaPC 264DP mainboard and daughtercard are specified to run within the
environment listed in Table 3–2.
Operating temperature10°C to 40°C (50°F to 104°F)
Storage temperature–55°C to 125°C (–67°F to 257°F)
Relative humidity10% to 90% with maximum wet bulb temperature
Rate of (dry bulb) temperature change 11°C/hour
3.3 Physical Parameters
The mainboard is a printed-wiring board (PWB) with the following dimensions:
•Length: 42.11 cm (16.58 in ±0.0005 in)
•Width: 33.02 cm (13.0 in ±0.0005 in)
•Height: 3.81 cm (1.5 in)
The daughtercard is a PWB with the following dimensions:
•Length: 30.48 cm (12.0 in ±0.0005 in)
•Width: 14.99 cm (5.905 in ±0.0005 in)
•Height: 6.40 cm (2.52 in ±0.0005 in)
3–2Power and Environmental Requirements
28°C (82°F) and minimum dew point 2°C (36°F)
±2°C/hour (20°F/hour ±4°F/hour)
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Page 47
AlphaPC 264DP Hole and Connector Specifications
3.4 AlphaPC 264DP Hole and Connector Specifications
Figure 3–1 shows the AlphaPC 264DP mainboard’s hole specifications.
Figure 3–4 shows the hole specifications for the daughtercard.
Figure 3–4 AlphaPC 264DP Daughtercard Hole Specification—Component Side
304.80 mm
(12.000 in.)
5.08 mm
(.2 in.)
2× 5.08 mm
(.2 in.)
149.99 mm
135.5 mm
(5.335 in.)
3× φ 3.99 mm
(.157 in.)
(5.905 in.)
5.08 mm
(.2 in.)
2× 5.08 mm
(.2 in.)
223.93 mm
(8.816 in.)
3–6Power and Environmental Requirements
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Page 51
21272 Core Logic Chipset Introduction
4
Functional Description
This chapter describes the fu nction al opera tion of the AlphaPC 264DP. It introdu ces
the 21272 core logic chipset (21272) and describes its implementation with the
21264 microprocessors and their supporting memory and I/O devices.
Information, such as bus timing and protocol, found in other specifications, data
sheets, and reference documentation is not duplicated here.
Note :For detailed descriptions of chipset logic, operations, and transactions,
refer to the 21272 chips’ specification. For details of the PCI interface,
refer to the PCI System Design Guide and the PCI Local Bus Specifica-tion.
4.1 21272 Core Logic Chipset Introduction
The 21272 provides a solution for designers developing uniprocessor or dual-processor systems using the 21264 microprocessor. The chipset provides a 256-bit
memory interface and includes the following three gate arrays:
•Cchip: Address and commands, 432-pin ESBGA
•Dchip: Data path, 304-pin ESBGA
•Pchip: PCI interface, 304-pin ESBGA
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Functional Description4–1
Page 52
Cchip Functional Overview
4.2 Cchip Functional Overview
The Cchip provides the control interface between the 21264 and 21272 chipset. In
addition, it provides control for the Dchips and Pchips. It also controls the memory
subsystem and TIGbus. The Cchip performs the following functions:
•Maintains queues to store addresses and commands
•Controls and moves data to and from arrays of main memory
•Responds to commands from the CPU
•Supports interrupts and flash ROM via the TIGbus
On the AlphaPC 264DP, the Cchip controls four arrays of SDRAM DIMMs. The
DIMMs can range in size from 32MB to 256MB. Note that there are two separate
256-bit paths and four arrays (two on each bus) on the AlphaPC 264DP.
The components of th e memory subsy stem are dist ributed between th e Cchip and the
Dchips. Together, the chips serve as an interface between the CPU and memory
subsystem (see Figure 4–1).
The following list summarizes the major features of the Cchip:
•Accepts requests from the Pchip and CPU
•Orders the arriving requests
•Selects the request and issues controls to the DRAMs
•Issues probes to the CPU for the selected requests
•Translates CPU PIO address to PCI and CSR addresses
•Issues commands to the Pchip for the selected request
•Issues responses to the Dchip for the DRAM accesses, the probe, and Pchip
responses
•Controls the TIGbus to manage interrupts and maintains CSRs, including those
that represent interrupt status
4.2.1 CPU Interface
The CPU and Cchip communicate wi th each other through the system port. The system port is made up of unidirec tional address and command buses. The Cchip sys tem
interface logic decodes the sysPort address for both CPU and DMA requests to
determine the action to take. It supports cacheable memory accesses, programmed
I/O, interrupts, Tig addresses, as well as accesses to 21272 CSR space.
4–2Functional Description
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Page 53
4.2.2 Memory Controller
This section summarizes memory organization and memory controller features.
4.2.2.1 Memory Organization
The Cchip supports up to four a rr ays of SDRAM ( Arra y 0–3 ), wher e ea ch array consists of four DIMMs. The AlphaPC 264DP has four 256-bit arrays.
Memory is accessed at 256 bits; however, because the AlphaPC 264DP must use
ECC, 288 bits are required. The maximum memory that is supported on the
AlphaPC 264DP is 4GB using 256MB DIMMs (16 total).
Figure 4–1 Memory Datapath
Cchip Functional Overview
21264
sysdata
Bcache
cmd/addr
4.2.2.2 Programmable Memory Timing
The memory control state machine performs its sequence of steps through all memory transactions. On memory read and write transactions, it communicates with the
Dchips so that data may be latched from the memdata bus or driven onto the
memdata bus respectively.
4.2.2.3 General-Purpose Logic
The Cchip provides an interface to logic such as presence detection, flash ROM,
interrupts, and configuration through the TIGbus. The addresses of these devices
and the data are transferred over the TigData lines. The TIGbus interface is implemented using a Quicklogic 2005-1PF FPGA.
21272
Dchips
padbus
Pchips
capbus
Cchip
memdata1
memdata0
Array 3Array 1Array 2Array 0
SDRAM addr/ctl
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Functional Description4–3
Page 54
Dchip Functional Overview
4.3 Dchip Functional Overview
This section provides a functional overview of the Dchips and describes the following data bus configurations:
•sysdata bus, between the Dchips and the CPUs
•memdata bus, between the Dchips and the memory arrays
•padbus, between the Dchips and the Pchips
The Dchips provide the data path from the 21264 to main memory. Although a minimum of two chips are required f or the memo ry interf ace using the 21272, eigh t chips
are used for the interface on the AlphaPC 264DP.
The chips contain the CPU, Pchip, and memory interface data paths, which includes
DMA and PIO queues.
The Dchips interface to the CPU using the sysdata bus. It interfaces with each Pchip
through the 32-bit padbus (communications path between the Pchip and Dchips,
padbus0 to Pchip0 and padbus1 to Pchip1). The Dchips function as the data path for
the CPU, memory, and I/O subsystem, and contain the fol lowing data path functi ons :
•DMA write data/PIO read data queue
•DMA read data/PIO write data queue
•Queues to allow full bandwidth transfers from memory to the CPU
•Queue to hold old memory data to be merged with the Pchip data for DMA
writes
4.3.1 Sysdata Bus
The sysdata bus, between the Dchips and each CPU, passes 128 bits of data (64 bits
[8 bytes] from each CPU). It is connected as follows:
•Dchip 0 connects to each of the two byte 0s.
•Dchip 1 connects to each of the two byte 1s.
•Dchip 7 connects to each of the two byte 7s.
Note:The bytes correspond to the bytes from CPU0 and CPU1.
4–4Functional Description
12 February 1999 – Subject To Change
Page 55
4.3.2 Memdata Bus
There are two memdata buses, each of which is a 256-bit, bidirectional bus between
the Dchips and the memory arr ays. Memda ta0 con nects t o arra ys 0 and 2; memdata1
connects to arrays 1 and 3 (see Figure 4–1).
Each Dchip sends/receives four bytes of data that it has accumulated to/from the
memory arrays. The connections are as follows:
•Dchip0 connects to bytes 0,8,16,24
•Dchip1 connects to bytes 1,9,17,25
•Dchip2 connects to bytes 2,10,18,26
•Dchip3 connects to bytes 3,11,19,27
•Dchip4 connects to bytes 4,12,20,28
•Dchip5 connects to bytes 5,13,21,29
•Dchip6 connects to bytes 6,14,22,30
•Dchip7 connects to bytes 7,15,23,31
Dchip Functional Overview
4.3.3 Padbus
The padbus is a 32-bit data bus that allows a Pchip and the Dchips to pass data back
and forth. If there are two Pchips, then padbus0 (32 bits) connects to Pchip0 and
padbus1 (32 bits) connects to Pchip1. The chips are connected in the following manner:
•Dchip0 connects to nibble 0, padbus0 and nibble 0, padbus1.
•Dchip1 connects to nibble 2, padbus0 and nibble 2, padbus1.
•Dchip2 connects to nibble 4, padbus0 and nibble 4, padbus1.
•Dchip3 connects to nibble 6, padbus0 and nibble 6, padbus1.
•Dchip4 connects to nibble 1, padbus0 and nibble 1, padbus1.
•Dchip5 connects to nibble 3, padbus0 and nibble 3, padbus1.
•Dchip6 connects to nibble 5, padbus0 and nibble 5, padbus1.
•Dchip7 connects to nibble 7, padbus0 and nibble 7, padbus1.
12 February 1999 – Subject To Change
Functional Description4–5
Page 56
Pchip Functional Overview
4.4 Pchip Functional Overview
The Pchip is the bridge between th e PCI and the CPU and its cac he and memory, and
the chip interface protocol is compliant w ith the PCI Local Bus Specification, Revi-
sion 2.1. The Pchip contains all control functions of the bridge and some data path
functions. Other data path functions reside in the Dchip.
Two Pchips are used on the AlphaPC 264DP to provide two separate 64-bit PCI
buses.
The Pchip provides all controls and interfaces to the PCI and contains the following
components and functions:
•Downsteam and upstream queues for address and data
4.4.1 PCI Interface
The PCI interface of the Pchip is a fully compliant PCI h ost bridge. It ac ts as a master on the PCI on CPU-initiated transactions and is a target on memory space transactions initiated by PCI mast ers.
The Pchip is not a PCI peripheral; it is a bridge between the PCI peripherals and
memory. The chip implements functions of a host bridge that are not sufficient to
interface the chip as a PCI peripheral component.
4–6Functional Description
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Page 57
4.5 Clock Subsystem
The system clocks can be divided into five areas:
•Input clocks required by the CPU/system
•Clock forwarding to/from the system logic
•Memory system
•PCI system
•Miscellaneous oscillators and clocks required for the peripheral interfaces and
functions
4.5.1 CPU and System Clock Generation
There is a crystal for 32.768 KHz, and ot her cloc ks ar e provided through a PC clock
generator chip. A 14.1818-KHz crystal is used as the input clock for the PC clock
generator.
A 32.768-KHz crystal provides input to the TOY function of the southbridge.
A 14.3-MHz oscillator (69.9-ns period) output is buffered from the PC clock genera-
tor to the ho st PCI-to-IS A bridge and the three ISA slots. This i s the standard
14.31818-MHz ISA clock.
Clock Subsystem
Figure 4–2 shows the clock distribution.
12 February 1999 – Subject To Change
Functional Description4–7
Page 58
PCI Devices
Figure 4–2 Clock Distribution
L2 Cache
Differential
+
-
PECL
Outputs
166 MHz
MC12439
167-MHz
PLL
X10
16.66-MHz
xtal
4.6 PCI Devices
The AlphaPC 264DP uses the PCI bus as the mai n I/O bus f or the majority of periph eral functions. The board implements the ISA bus as an expansion bus for system
support functions and peripheral devices.
Divide
by 1
Divide
by 2
Differential
PECL
fwdclk
166 MHz
sysclk
83 MHz
osc
frame
Control
(2V OD)
fwdclk
sysclk
fwdclk
sysclk
fwdclk
sysclk
21264
Cchip
Dchips (8)
Pchips (2)
PLL
Cache Address,
Control and Clocking
Forwarded
Forwarded
Clocks
3.3-V Data3.3-V Control
pciclk
83 MHz
Clocks
pclk[7:0]
CPU to Cchip and
Dchip interfaces are
clock forwarded.
166-MHz clock is
used to clock data
on both edges.
3.3-V Rail-to-Rail
CMOS Interface
Main Memory
SDRAM DIMMs
Ta ble 4–1 shows the IDSEL assignment for all the PCI devices.
The PCI0 supports the southbridge chip, three PCI slots, and the SCSI chip.
4.6.1.1 Southbridge Chip
The southbridge provides the bridge between the PCI bus and the Industry Standard
Architectu re (ISA) bus. The southb ridge incorporates the logic for the following:
•A PCI interface (master and slave)
•An ISA interface (master and slave) (see Section 4.8)
•Enhanced 7-channel DMA controller that supports DMA transfers and scatter-
gather, and data buffers to isolate the PCI bus from the ISA bus
PCI Devices
•An IDE interface, with a maximum cable length of 12 inch es
•A 14-level interrupt controller
•A 16-bit BIOS timer
•Three programmable timer counters
•Non-maskab le interrupt (NMI) control logic
•Decoding and control for utility bus peripheral devices
•Speaker driver
•PCI arbitration control (disabled on AlphaPC 264DP). Refer to the Cypress
hyperCache chipset databook for additional information.
4.6.1.2 PCI0 Expansion Slots
Three PCI bus expansion slot s are available on PCI0, with support for 64- bit devices.
Note that 3.3 V and +5 V are provided to the appropriate PCI connector pins.
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Functional Description4–9
Page 60
PCI Devices
4.6.1.3 PCI SCSI Interface
The Adaptec AIC7895 is used as a bridge from PCI to SCSI. The AIC7895 has two
ultra SCSI ports and is packaged in a 208-pin plastic quad flat pack (PQFP). Both
ports support ultrawide SCSI devices. Note that parity must be disabled for the
SRAM that attaches to the AIC7895.
4.6.2 PCI1
Three PCI bus expansio n slots are available on P CI1, with one slot shared with the
ISA. All three sl ots suppo rt 64-bi t devic es. Note that 3.3 V and +5 V are pr ovided to
the appropriate PCI connector pins.
4.6.3 PCI Arbitration
Arbitration logic is implemented in the Pchips, and the scheme is flexible and software programmable. Note, however , that Pchip1 handl es the arbitrat ion for PCI1, but
the TIGbus FPGA is the arbiter for PCI0. The arbitratio n logic in the sout hbridge and
in Pchip0 is disabled.
PCI0 Arbitration Scheme
The arbitration is controlled by the TIGbus FPGA, using a dual round-robin priority
scheme. There are two rings, A and B, wit h the scheme shown i n Figure 4–3. Ring A
has a round-robin priority between Pchip0, SCSI controller, slot 0, and the designated device from ring B. Ring B has a round-robin priority between slot 2, slot 1,
the southbridge bridge request, and the southbridge USB request.
Figure 4–3 PCI0 Arbitration Scheme
Controller
Pchip0
Slot 1
Southbridge
4–10 Functional Description
SCSI
Ring A
Arbiter
Slot 2
Ring B
Arbiter
USB
Slot 0
Southbridge
Bridge
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Page 61
PCI1 Arbitration Scheme
The arbitration for PCI1 is handled by Pchip1. It is a simple round-robin scheme
between slots 0, 1, and 2.
4.7 PCI and System Interrupts
Interrupt logic is implemented in the Cchip and the FPGA. The interrupt lines from
the PCI slots, southbridge chip, and SCSI chip are connected directly to the IRQ
buffers that reside on the TigData bus. They are driven onto the TigData bus by the
encoded TIGADR signals. The AlphaPC 264DP has 34 interr upt s tha t ar e shown in
Figure 4–4.
All PCI interrupts are combined in the Cchip and driven out onto the TIGbus. There
is also a Cchi p error interrupt and an I/O c ontroller error interrupt within the Cchip.
The CPU interrupt assignment, during normal operation, is listed in Table 4–2.
The Cchip Tig controller polls interrupts continuously except when any other TIG-
bus access is requested. The 48 interrupt inputs (34 enabled, 14 reserved) implemented on the AlphaPC 264DP are polled eight at a time by selecting a byte using
tigadr[2:0] and asserting TigIntOE to allow the selected byte to be driven on the
TIGbus. Once all the interrupts are polled, the Cchip drives the irq[3:0] data to the
two CPUs on to tigdata[7:0] and asserts TigIS to strobe it to the flip flop th at drives
it into the CPU.
cpu_irq0PchipsError interrupts
cpu_irq1PCI/ISA devicesPCI and ISA interrupts
cpu_irq2rtc_irqReal-time clock interrupt
cpu_irq3c_chip_csrInterprocessor
cpu_irq4Halt jumper or softwareHalt for each processor
cpu_irq5Reserved—
The ISA bus interrupts (IRQ0 through IRQ8 and IRQ12 through IRQ14) are all
nested through the southbridge (on INT output) to the Cchip (via the TIGbus) and
then into the CPU. The interrupt assignment is configurable but is normally used as
shown in Table 4–3.
4–12 Functional Description
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Page 63
Table 4–3 ISA Interrupts
ISA Devices
Interrupt
LevelInterrupt Source
IRQ0Interval timerIRQ8Reserved
IRQ1KeyboardIRQ916-bit ISA
IRQ2Chains interrupt from slave peripheral
interrupt controller
IRQ38-bit ISA (COM2)IRQ1116-bit ISA
IRQ48-bit ISA (COM1)IRQ12Mouse
IRQ58-bit ISA (parallel port)IRQ1316-bit ISA
IRQ68-bit ISA (floppy disk)IRQ1416-bit ISA
IRQ78-bit ISA (parallel port)IRQ15IDE
The AlphaPC 264DP timer inter rup t is generated by the real- t ime c loc k by mea ns of
the square-wave output of the southbr idge ch ip, which route s the inter rupt direc tly to
the Cchip.
4.8 ISA Devices
The following section describes the AlphaPC 264DP ISA bus implementation with
peripheral devices and connectors.
Interrupt
LevelInterrupt Source
IRQ1016-bit ISA
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Functional Description 4–13
Page 64
DC Power Distribution
4.8.1 Super I/O Controller
The AlphaPC 264DP uses the SMC FDC37C669 as the combination controller chip
(see Table 2–1 and Figure 2–1). It is packaged i n a 100-p in PQFP config urati on. The
chip provides the following ISA peripheral functions:
•Diskette controller – Software compatible with the Intel PC8477 (contains a
superset of the Intel DP8473 and NEC PD765 and the Intel N82077 FDC functions). The onchip analog data separator requires no external filter components
and supports the 4Mb drive format and 5.25-inch and 3.5-inch diskette drives.
FDC data and control lines are brought out to a standard 34-pin connector. A
ribbon cable interfaces the connector to one or two diskette drives.
•Serial ports – Two UARTs with modem control, compatible with NS16450 or
PC16550, are brought out to separate onboard, 10-pin connectors. The lines can
be brought out thr ough 9-pin female D-sub co nnec tors on the bulkhead of a st andard PC enclosure.
•Parallel port – The bi direc tiona l p arall el po rt is br ought out to an onboard 25-pi n
connector. It can be brought out through a 25-pin female D-sub connect or on the
bulkhead of a standard PC enclosure.
Refer to the SMC FDC37C669 specification for further information (including timing, electrical characteristics, and mechanical data).
4.8.2 ISA Expansion Slot
One ISA expansion slot is provided for plug-in ISA peripherals. This slot is shared
with the PCI and can be used for a PCI or ISA device.
4.9 DC Power Distribution
The AlphaPC 264DP derives its system power from a user-supplied power supply.
The power supply must provide +1 2 V dc, −12 V dc, −5 V dc, +5 V dc, 5VSB dc and
3.3 V dc. The dc power is supplied through two power connectors on the mainboard
(J3 and J33) and one on the daughter card (J4). Power is distribu ted to the board log ic
through dedicated power planes within the 12-layer board structure. Power is distributed to the daughtercard through the connector and dedicated 18-pin power connector from the power supply.
4–14 Functional Description
12 February 1999 – Subject To Change
Page 65
DC Power Distribution
Figure 4–5 shows that t he +12 V dc , −12 V dc, + 5 V dc, and −5 V dc are sup pli ed to
ISA connector J47. The +12 V dc and −12 V dc are supplied to the PCI connectors
J35, J40–42, J44, and J46, and to the two daughtercard connectors J18 and J23. The
+12 V dc is also supplied to the fan box connectors J2, J15, J22, and J24.
In addition to the ISA connector, +5.0 V dc is supplied to the PCI connectors and to
most of the board’s integrated circuits.
The +3.3 V dc is provided to the PCI slots, the 21272 core lo gic chipse t, the DIMMs,
the daughtercard connectors, and the linear regulator that provides the 2.0-V termination voltage to the mainboard and the daughtercard connectors.
The power supply also provides 5 VSB to the comm port (J19) and soft power.
Figure 4–5 also shows that the daught ercard re ceives +5 V dc from the power sup ply
and distributes it to the dc-to-dc converter and miscellaneous logic on the card. The
daughtercard edge connector (J3) provides the following voltages from the mainboard:
•+3.3 V for the SSRAMs, miscellaneous logic on the card, and for the linear reg-
ulator for conversion to 1.5 V for SSRAM I/O
•+12 V for fan power and RS-232 logic
•–12 V for RS-232 logic
•+2.0 V for termination logic
12 February 1999 – Subject To Change
Functional Description 4–15
Page 66
Reset and Initialization
Figure 4–5 AlphaPC 264DP Power Distribution
J33
15
−12 V
1, 3, 5, 7,
10, 12, 14
16
J3
12
1, 3, 5, 7,
9, 11, 14,
16, 18, 20
24
J4
1, 3, 5, 7,
9, 11, 13,
15, 17
+5 V
−5 V
+12 V
+3.3 V
+5VSB
+5 V
dc-to-dc
Converter
ISA Conn.
Comm.
Port
MISC
+2.2 V
PCI32
Conn.
21272
MISC
21264
Spkr
Conn.
DIMMs
SSRAMs
Integrated
Circuits/Clocks
Linear
Regulator
Mainboard
Daughtercard
Linear
Regulator
+1.5 V
SSRAM
I/O
Termination
Fans
Comm.
Port
+2.0 V
Termination
RS-232
MISC
Fans
+3.3 V
+2.0 V
+12 V
−12 V
Daughter-
card
Conn.
J3
1-8, 91-98
87-90,
177-180
176
86
4.10 Reset and Initialization
This logic is contained on the daughtercard in a Quicklogic QL12X16BL FPGA.
This controls reset, power OK, SROM test port, and interrupts to the CPU.
The TIGbus FPGA will implement system irq, general configuration registers, and
Motorola synthesizer setup based on CPU speed and 21272 speed. It will also provide the interface to the flash ROM.
4–16 Functional Description
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Page 67
4.11 System Software
The AlphaPC 264DP software is divided into the following categories:
•Serial ROM code
•Flash ROM code
•Operating systems
4.11.1 Serial ROM Code
The serial ROM code i s c ont ai ned in a 512KB flash ROM. The serial ROM code initializes the system, which includes loading Debug M onitor or other code from the
flash ROM. The serial ROM code then transfers control to the code loaded from the
flash ROM.
The Mini-Debugger is also resident in the SROM. Switch 4 can be set on SW2 (see
Section 2.2) for CPU0 and CPU1 to trap to the Mini-Debugger. Connector J2 on the
daughtercard provides a terminal port for the Mini-Debugger.
4.11.2 Flash ROM Code
System Software
The AlphaPC 264DP includes an industry-standard, 2MB flash ROM – AMD
AM29F016.
4.11.3 Operating Systems
The AlphaPC 264DP is designed to run Windows NT and Tru64 UNIX.
12 February 1999 – Subject To Change
Functional Description 4–17
Page 68
Page 69
System Memory and Address Mapping
5.1 Memory Subsystem
The DRAM memory subsystem on the AlphaPC 264DP consists of sixteen 200-pin
buffered DIMM slots, which are organized as four arrays of memory. The 21272
chipset supports t wo 256-bit me mory buses (288-b it i ncludi ng ECC) with t wo arr ays
on each bus (see Figure 5–1).
The 72-bit, 100-MHz DIMMs consist of 64 bits of data and 8 bits of ECC, and can
be 32MB, 64MB, 128MB, or 256MB. The minimum conf iguration (one array populated with four 32MB DIMMs) is 128MB. The maximum configuation (four arrays
each populated with four 256MB DIMMs) is 4GB.
Memory Subsystem
5
The memory cycle time is 83 MHz, identical to the 21272 chipset cycle time.
Note:Although the memory cycle time is 83 MHz, qualified 100-MHz
DIMMs are r equired.
Figure 5–1 AlphaPC 264DP Memory Subsystem
21264
12 February 1999 – Subject To Change
21272
Dchips
Pchips
Cchip
Data Bus 1
Data Bus 0
Address/Control
Array 3Array 1Array 2Array 0
System Memory and Address Mapping5–1
Page 70
Configuring SDRAM Memory
5.2 Configuring SDRAM Memory
For the memory system in the AlphaPC 264DP, one to four arrays may be used, following the configuration rules.
Configuration Rules
•Each array must be fully populated with DIMMs of the same size and type.
•Array 0 must be populated.
•Additional arrays can be populated in any order.
For a memory subsystem with two arrays, placing the second array on bus 1
(array 1 or array 3) is recommended.
Arrays
The arrays are made up of the following connectors:
•Array 0: J11, J14, J26, J28
•Array 1: J1, J6, J30, J32
•Array 2: J13, J16, J25, J27
•Array 3: J5, J9, J29, J31
Figure 5–2 shows the relationship of the connectors/arrays. Refer to Figure 1–1 for
DIMM connector locations on the mainboard.
Figure 5–2 AlphaPC 264DP DIMM Connectors
(array 1)
J1
(array 3)
J5
J6
(array 1)
(array 3)
(array 0)
(array 2)
(array 0)
(array 2)
Bus 0Bus 1
(array 2)
(array 0)
(array 2)
(array 0)
5–2System Memory and Address Mapp ing
J9
J11
J13
J14
J16
Cchip
J25
J26
J27
J28
J29
J30
J31
J32
(array 3)
(array 1)
(array 3)
(array 1)
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Page 71
Configuring SDRAM Memory
Possible Configurations
Memory sizes from 128MB to 4GB are supported.
Although not an exhaustive list, Table 5–1 lists some of the SDRAM memory configurations ava ilabl e. Any co mbina tions of DI MMs th at meet th e confi gurat ion ru le s
are supported by the 21272 chipset.
For a list of vendors who supply components and accessories for the
AlphaPC 264DP, see Appendix A.
This section describes the mapping of the processor physical address space into
memory and I/O space addresses. It also includes the translations of the processorinitiated address into a PCI address, and PCI-initiated addresses into physical memory addresses.
5.3.1 CPU Address Mapping to PCI Space
The physical sysbus address space is composed of the following:
•Memory address space
•Local I/O space, for registers residing on the sysbus (that is, registers in the
Cchip, Dchips, and Pchips)
•PCI space
The PCI defines four physical address spaces, as follows:
•PCI memory space (for memory residing on the PCI)
•PCI I/O space
•PCI configuration space
•PCI interrupt acknowledge cycles /PCI special cycles
Refer to the 21272 functional specification for details in this area.
111801 38xx x000 ROGpen_6 CPU1_config[7:0] CPU1 configuration register. See
Figure 5–5.
801 38xx x040 RAZReserved—
801 38xx x080 WOPCI_0_ok[0]PCI0 self-test register.
801 38xx x0C0 WOPCI_1_ok[0]PCI1 self-test register.
801 38xx x100 RWSoft_reset[0] To set a hardware reset for a short
801 38xx x140 ROTig_PAL_rev[7:0]Bits [7:5] specify the major revision
801 38xx x180 ROArbiter_rev[7:0]Bits [7:5] specify the major revision,
801 38xx x1C0 RWFeature_mask[7:0] See Figure 5–6.
1
These are two separate halt registers.
12 February 1999 – Subject To Change
period of time, first write a 0, then
write a 1 to this location.
(corresponding to the board revi-
sion), [4:0] specify the minor revi-
sion.
[4:0] specify the minor revision.
System Memory and Address Mapping5–5
Page 74
System Address Mapping
The Gpen4 register, shown in Figure 5–3, reflects the settings of the mainboard’s
switchpack 2 (see Figure 2–3).
The Gpen5 register, shown in Figure 5–4, shows the CPU speed and Bcache configuration (set by onboard resistors) on the daughtercard containing CPU0.
Figure 5–4 Gpen5 Register
76543210
cpu0_speed[2:0]
bc0_config[3:0]
cpu0_present_l
The Gpen6 register, shown in Figure 5–5, shows the CPU speed and Bcache configuration (set by onboard resistors) on the daughtercard containing CPU1.
Figure 5–5 Gpen6 Register
76543210
cpu1_speed[2:0]
bc1_config[3:0]
cpu1_present_l
The feature mask regist er, shown in Figure 5–6, allows you to set the Cypress chip’s
arbiter activity.
Figure 5–6 Feature Mask Register
7 6543210
5–6System Memory and Address Mapp ing
RAZ
Arbiter select.
0Selects the arbiter that deasserts the Cypress chip’s grant
1Selects the arbiter that holds the assertion of the Cypress
after it claims the transaction.
chip’s grant until it has deasserted its request.
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Page 75
Support, Products, and Documentation
A.1 Customer Support
Alpha OEM provides the following web page resources for customer support.
URLDescription
http://www.d igital.com/alphaoem
Contains the following links:
•Developers’ Area: Development tools, code examples,
driver developers’ information, and technical white
papers
•Motherboard Products: Motherboard details and
performance information
•Microprocessor Products: Microp rocesso r det ai ls and
performance information
•News: Press releases
•Technical Information: Motherboard firmware and
drivers, hardware compatibility lists, and product
documentation library
A
•Customer Support: Feedback form
12 February 1999 – Subject to Change
Support, Products, and DocumentationA–1
Page 76
Supporting Products
A.2 Supporting Products
This section lists sources for components and accessories that are not included with
the AlphaPC 264DP.
A.2.1 Memory
Dual inline memory modules (DIM Ms) are availabl e from a variety of vend ors. For a
list of the qualified vendors, visit the Alpha OEM World Wide Web Internet site at
URL:
http://www.digital.com/alphaoem
Click on Technical Information.
Then click on
A.2.2 Power Supply
A power supply, suitable for use with the AlphaPC 264DP (+3.3 V, +5 V, –5 V,
+12 V, –12 V), is available from:
The following table li st s s ome of the available Alpha document ati on. You can download Alpha documentation from the Alpha OEM World Wide Web Internet site: