Epson SCE8720C Series User manual

MF1286-02
SEIKO EPSON CORPORATION
CARD-PCI/GX
Hardware Manual

NOTICE:
No part of this material may be reproduced or duplicated in any form or by any means
without the written permission of Seiko Epson. Seiko Epson reserves the right to make
changes to this material without notice. Seiko Epson does not assume any liability of any
kind arising out of any inaccuracies contained in this material or due to its application or use
in any product or circuit and, further, there is no representation that this material is
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export license from the Ministry of International Trade and Industry or other approval from
anther government agency.
©SEIKO EPSON CORPORATION 2000 All rights reserved.
CompactFlash is a trademark of Sandisk Corporation in U.S.A. CompactFlash is licensed
to CFA (CompactFlash Association).
Windows and Windows NT are registered trademarks of Microsoft Corporation in U.S.A.
Geode is a trademark of National Semiconductor Corporation in U.S.A.
PC/AT is a registered trademark of International Business Machines in U.S.A.
All other product names mentioned herein are trademarks and/or registered trademarks of
their respective companies.

CARD-PCI/GX Hardware Manual
Rev.A EPSON i
CONTENTS
CONTENTSCONTENTS
CONTENTS
1.
1.1.
1. Overview
OverviewOverview
Overview ................................
................................................................
................................................................
................................................................
................................................................
................................................................
.........................................................
..................................................
.........................1
11
1
1.1 System Overview.............................................................................................................2
1.2 Basic Specification .......................................................................................................... 3
1.3 BIOS ................................................................................................................................5
1.4 Memory map....................................................................................................................6
1.5 I/O map............................................................................................................................7
1.6 DMA controller.............................................................................................................. 13
1.7 System interrupts ......................................................................................................... 14
1.8 Timer counter................................................................................................................ 15
1.9 Real time clock and C-MOS RAM.................................................................................16
2.
2.2.
2. Mechanical specifications
Mechanical specificationsMechanical specifications
Mechanical specifications................................
................................................................
................................................................
................................................................
..............................................................
............................................................
.............................. 17
1717
17
2.1 Dimensions and weight................................................................................................. 17
2.2 Installation method....................................................................................................... 17
3.
3.3.
3. Interface specifications
Interface specificationsInterface specifications
Interface specifications................................
................................................................
................................................................
................................................................
................................................................
................................................................
..................................
....
.. 18
1818
18
3.1 Pin configuration........................................................................................................... 18
3.1.1 280-pin connector pin configuration ...................................................................... 19
3.1.2 20-pin connector pin configuration........................................................................ 19
3.2 Signal characteristics.................................................................................................... 21
3.3 Descriptions on signal functions...................................................................................27
3.3.1 PCI bus...................................................................................................................27
3.3.2 LIMITED ISA bus.................................................................................................. 28
3.3.3 LCD........................................................................................................................30
3.3.4 CRT ........................................................................................................................31
3.3.5 Hard disk (IDE) ..................................................................................................... 31
3.3.6 USB........................................................................................................................31
3.3.7 Serial interfaces..................................................................................................... 32
3.3.8 Parallel interfaces.................................................................................................. 33
3.3.9 Keyboard/mouse .................................................................................................... 35
3.3.10 AC97 interfaces...................................................................................................... 35
3.3.11 Power management............................................................................................... 36
3.3.12 Power supply.......................................................................................................... 37
3.3.13 FDD........................................................................................................................ 37
4.
4.4.
4. Detailed description of interfaces
Detailed description of interfacesDetailed description of interfaces
Detailed description of interfaces................................
................................................................
................................................................
................................................................
..................................................
....................................
.................. 38
3838
38
4.1 CRT, LCD.....................................................................................................................38
4.2 Hard disk ..................................................................................................................... 40

CARD-PCI/GX Hardware Manual
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4.3 FDD.............................................................................................................................. 41
4.4 Keyboard/mouse........................................................................................................... 42
4.5 Parallel port................................................................................................................. 43
4.6 Serial port .................................................................................................................... 44
4.7 USB.............................................................................................................................. 44
4.8 Speaker ........................................................................................................................ 45
4.9 PCI ............................................................................................................................... 45
4.10 LIMITED ISA .............................................................................................................. 46
4.11 RTC .............................................................................................................................. 46
5.
5.5.
5. Power management
Power managementPower management
Power management ................................
................................................................
................................................................
................................................................
................................................................
................................................................
.......................................
..............
....... 47
4747
47
5.1 Power ON/OFF............................................................................................................. 47
5.2 Standby mode .............................................................................................................. 47
5.3 Power supply................................................................................................................47
5.4 Power sequence............................................................................................................ 49
5.4.1 Power sequence (for power supply which is turned ON/OFF from the software)........... 49
5.4.2 Power sequence (for power supply which is not turned ON/OFF from the software) ..... 51
6.
6.6.
6. Electrical characteristics
Electrical characteristicsElectrical characteristics
Electrical characteristics................................
................................................................
................................................................
................................................................
...............................................................
..............................................................
............................... 52
5252
52
6.1 Absolute maximum rating........................................................................................... 52
6.2 Recommended operating condition............................................................................. 52
6.3 DC characteristics (under recommended operating condition).................................. 53
6.3.1 PCI bus...................................................................................................................53
6.3.2 LIMITED ISA bus.................................................................................................. 53
6.3.3 LCD........................................................................................................................54
6.3.4 CRT ........................................................................................................................54
6.3.5 FDD........................................................................................................................55
6.3.6 IDE......................................................................................................................... 55
6.3.7 Serial port .............................................................................................................. 56
6.3.8 Parallel port........................................................................................................... 56
6.3.9 Keyboard/mouse .................................................................................................... 57
6.3.10 USB........................................................................................................................ 57
6.3.11 Power management signal .................................................................................... 57
6.3.12 AC97....................................................................................................................... 58
6.3.13 Other signals.......................................................................................................... 59
6.4 Current consumption................................................................................................... 60
6.4.1 Maximum current value........................................................................................ 60
6.4.2 Typical current value 1 ......................................................................................... 60
6.4.3 Typical current value 2 ......................................................................................... 61

CARD-PCI/GX Hardware Manual
Rev.A EPSON iii
6.4.4 Standby current..................................................................................................... 61
7.
7.7.
7. AC characteristics
AC characteristicsAC characteristics
AC characteristics................................
................................................................
................................................................
................................................................
................................................................
................................................................
..........................................
....................
.......... 62
6262
62
7.1 PCI timing.................................................................................................................... 62
7.2 USB timing .................................................................................................................. 62
7.3 LIMITED ISA timing................................................................................................... 62
7.3.1 Memory, I/O read cycle timing.............................................................................. 62
7.3.2 Memory, I/O write cycle timing............................................................................. 64
7.4 AC97 timing.................................................................................................................65
7.5 TFT timing...................................................................................................................65
8.
8.8.
8. Cautions on use
Cautions on useCautions on use
Cautions on use ................................
................................................................
................................................................
................................................................
................................................................
................................................................
.............................................
..........................
............. 66
6666
66
Appendix
AppendixAppendix
Appendix A.
A.A.
A. Peripheral circuit design
Peripheral circuit designPeripheral circuit design
Peripheral circuit design ................................
................................................................
................................................................
................................................................
..............................................
............................
.............. 67
6767
67
A.1 IO extension of PCI bus...............................................................................................67
A.1.1 Number of PCI devices..........................................................................................67
A.1.2 PCI device No. and wiring method for interrupts................................................ 68
A.1.3 Connection of 5V device to PCI bus...................................................................... 69
A.2 IO extension of LIMITED ISA bus.............................................................................. 70
A.2.1 Address decoding................................................................................................... 70
A.2.2 Pull-up of SD/SA[7:0]............................................................................................. 70
A.2.3 SA[15:0] latch ........................................................................................................ 71
A.2.4 Number of ISA slots ..............................................................................................71
A.2.5 Pull-up resistance of IOCHRDY............................................................................ 71
A.2.6 SMEMR# and SMEMW# generation ....................................................................72
A.2.7 MEMCS16# generation ......................................................................................... 72
A.3 Power supply design: Power control circuit................................................................ 73
A.3.1 Power not requiring ON/OFF by software............................................................73
A.3.2 Power requiring ON/OFF by software.................................................................. 74
A.3.3 Cautions on compatibility of CARD-PCI .............................................................. 75
A.3.4 Wake on LAN signal.............................................................................................. 75
A.4 Cautions on artwork design ........................................................................................ 76
A.4.1 Power supply line .................................................................................................. 76
A.4.2 Address bus and data bus .....................................................................................77
A.4.3 PCI signal .............................................................................................................. 77
A.4.4 Clock signal............................................................................................................ 77
A.4.5 CRT RGB signal..................................................................................................... 78
A.4.6 Reset signal............................................................................................................ 78
Appendix
AppendixAppendix
Appendix B.
B.B.
B. Timing examples of power management signals
Timing examples of power management signalsTiming examples of power management signals
Timing examples of power management signals................................
................................................................
..........................................
....................
.......... 79
7979
79

CARD-PCI/GX Hardware Manual
Rev.A EPSON 1
1.
1.1.
1. Overview
OverviewOverview
Overview
SCE8720Cxx (CARD/PCI/GX) is the first product in SEIKO EPSON’s CARD-PCI series
equipped with the PCI bus. With the PCI bus, ability of enhancement, which enables
various PCI devices to be connected, is realized.
By utilizing the Geode 200 MHz low voltage product, which comprises CPU core, and the
companion chip manufactured by National Semiconductor, low power consumption, low
cost and high quality display (CRT1280 ×1024, 256-color) are all realized. Especially, this
low power consumption capability is one of the most important aspects to realize fan-less,
which is required in applications requiring high liability.
All these capabilities are provided within a compact size of 101.6 ±1.0 ×63.5 ±0.3 ×16.0 ±
1.0 (mm) with 280-pin and 20-pin interface connectors.
Because SCE8720C can easily enable the core capabilities of IBM PC/AT, including BIOS,
users can drastically decrease system development manpower and period.
In addition, future CARD-PCI series will also be able to be used with the same main board
only requiring consideration on the card’s mounting area and power supply.

CARD-PCI/GX Hardware Manual
EPSON Rev.A
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1.1 System Overview
SCE8720Cxx (CARD-PCI/GX) is provided with almost all the functions usually equipped
on a mother board. These functions are accessed via the 280-pin main connector and 20-
pin connector.
As for 280-pin connector, manufacturer’s genuine part is utilized. Functions accessed via
the 280-pin connector are PCI extended bus, CRT or TFT LCD panel display, 2-channel
USB, primary IDE, LIMITED ISA extended bus (*1), keyboard and mouse, 2-channel
serial/parallel port and AC97 interface. FDD and a part of interrupt of ISA are accessed
via the 20-pin connector.
SCE8720Cxx has Geode GX-LV 200MHz (CPU CHIP), Geode CS5530 (Companion chip),
97317 (Super IO) all built-in. As the main memory, SCE8720Cxx has a 32MB or 64MB of
synchronous D-RAM and has utilized the unified memory method, in which a part of the
synchronous D-RAM is used as the display memory. Generally, it is said that the unified
memory method results in low-performance. However, with SCE8720Cxx, high
performance is realized by compressing the data for display refreshing. In addition,
SCE8720Cxx has a built-in CPU core power regulator (VRM) and a built-in CLOCK
generator with built-in PLL. (*1: LIMITED ISA = ISA with limited capability)
Geode GXLV
(CPU&North)
200MHz 2.2V
CS5530
(South&display)
PC97317(Super IO)Flash BIOS
256KB
SDRAM
32/64MB
Main
Memory&
V-RAM
280pin
Connector
20pin
Connector
Clocks VRM
PCI expansion
AC97
CRT
TFT
USB*2CH
IDE
LIMITED ISA expansion
KB/MOUSE
Serial*2CH
Parallel
FDD
Figure1.1 Block diagram of SCE8720Cxx

CARD-PCI/GX Hardware Manual
Rev.A EPSON 3
1.2 Basic Specification
Item Specifications
CPU Geode GXLV 200MHz (Manufactured by National
Semiconductor)
(Cache memory 16KB built-in, FPU built-in)
Main memory Synchronous DRAM 32MB/64MB
System ROM 256KB
(System BIOS + VGA BIOS + Power management BIOS)
Companion chip Geode CS5530 (Manufactured by National Semiconductor)
(Graphic control, IDE AC97 etc.)
Graphic function RAM Maximum 4MB (using a part of synchronous DRAM)
CRT 60Hz (Max. XGA: 64K-color or SXGA: 256-color)
TFT 18/12/9-bit TFT panel support (Max. XGA 64K-color)
STN cannot be used.
I/O interface
PCI 3.3V PCI Version 2.1 Compliance (33MHz)
PCI device 3 PCI master 2
LIMITEDISA No DMA or Master function provided. As for AB0-15, multiplex
output to DB.
Some signals have been deleted as well.
Parallel 1-port SPP, ECP, EPP (rev1.9/1.7) supported.
Serial 2-port (16550 compatible) Max.1.5Mbaud
HDD(IDE) 1 device (ANSI ATA_4 Compliant)
FDD 1 device (720/1.44MB 2mode, 3.5”)
Keyboard 1PS/2-compatible
Mouse 1PS/2-compatible
USB 2-port, USB Revision 1.0 compliant
Speaker PC beep
AC97 Version 2.0
Super I/O PC97317 (Manufactured by National Semiconductor)
RTC MC146818A-compatible, built in Super I/O.
Clock buffer MK1491-06 (Manufactured by ICS)
Outside dimensions 101.6±1.0×63.5±0.3×16.0±1.0 (mm)
Weight Approx. 82g

CARD-PCI/GX Hardware Manual
EPSON Rev.A
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Operation environment (temperature ranges)
Maximum temperature [Tc = 75°C right above the heat sink, and Ta = 70°C around the
SDRAM]
Minimum temperature Ta = 0°C
Figure 1.2 Temperature measurement position
Storage environment Temperature -20 to 75°C (no condensation)
Humidity 0to90%(nocondensation)
Current consumption Maximum rating 7.1W
Power supply specifications (the following power supply is required.)
The following operational values are measured when Windows 98 is running and
desktop is displayed.
CPU_VRM power supply (VCCCORE) 5V
Current consumption Typ. 408mA
Standby current Typ. 17.2 mA
System power (VCC3V)3.3V
Current consumption Typ. 620 mA
Standby current Typ. 230 mA
ISA bus power supply (VCC5V)5V
Current consumption Typ. 17.1 mA
Standby current Typ. 11.5 mA
5V standby power (VCCSTB) 5V
(Power of 5V is always supplied regardless of the ON/OFF of the power
supply.)
Current consumption Typ. 0.35 mA
Backup power (VCCBAK) 2.7 to 3.6V (voltage supplied by battery)
Current consumption Typ. 1.2 µA
(WhenholdingtheC-MOSmemorycontentsbythebattery)
1
2
2
1: Heat sink on CPU
2: Ta around DRAM (peripheral temperature)

CARD-PCI/GX Hardware Manual
Rev.A EPSON 5
 Power management
Power ON (PME0#, 1#, power SW)
Power OFF (Soft OFF)
Standby mode
1.3 BIOS
SCE8720C has adopted AWARD BIOS manufactured by Phoenix. It has the power
management and plug-and-play functions. With the BIOS setup menu, many
configuration parameters can be set.
The Video BIOS is also stored in the same ROM.

CARD-PCI/GX Hardware Manual
EPSON Rev.A
6
1.4 Memory map
BIOS
Video Memory
Video BIOS (*2)
00000000
000A0000
000C0000
000C8000
000E0000
000FFFFF
Conventional
Memory
00000000
00100000
FFFC0000
FFFFFFFF
4000000-α
BIOS
ISA
Reserved
Memory
S=DRAM (*1)
(S-DRAM)
2000000-α
*1: Memory size can be 32MB or 64MB, depending on the model.
*2: With some types of Video, C0000h to CBFFFh can be occupied as VIDEO BIOS.
α: Area for the video memory: Max. 4MB
Figure 1.3 Memory map

CARD-PCI/GX Hardware Manual
Rev.A EPSON 7
1.5 I/O map
The I/O addresses 000h to 0FFh are assigned to the basic I/O. Although the addresses
from 100h to 3FFh are for the ISA bus, SCE8720C has pre-built-in I/O.
These I/O addresses cannot be used when additionally setting I/O. I/O map is as follows:
Table 1.1 I/O map
I/O Address Register Function
000h-01Fh 00h RW DMA Channel 0 Base and Current
Address
01h RW DMA Channel 0 Base and Current Word DMA Controller 1
02h RW DMA Channel 1 Base and Current
Address (82C37A equivalent)
03h RW DMA Channel 1 Base and Current Word
04h RW DMA Channel 2 Base and Current
Address
05h RW DMA Channel 2 Base and Current Word
06h RW DMA Channel 3 Base and Current
Address
07h RW DMA Channel 3 Base and Current Word
08h WO Command Resister
08h RO Status Register
09h WO Request Register
0Ah WO Single-Mask Register
0Bh WO Mode Register
0Ch WO Clear Byte Pointer
0Dh RO Master Clear
0Dh WO Temporary Register
0Eh WO Clear Mask Register
0Fh WO Write all Mask Register
020h-021h 20h WO Initialization Control Word ICW1
20h WO Operation Control Word OCW2
20h WO Operation Control Word OCW3
20h RO Interrupt Service Resister
Interrupt
Controller 1
(82C59A
equivalent)
20h RO Interrupt Request Resister
21h WO Initialization Control Word ICW2
21h WO Initialization Control Word ICW3
21h WO Initialization Control Word ICW4
21h RW Operation Control Word OCW1
21h RW Interrupt Mask Resister

CARD-PCI/GX Hardware Manual
EPSON Rev.A
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I/O Address Register Function
22h WO Configuration Index Register022h-2Dh 23h RW Configuration Data Register Geode GX-LV
2Eh RW Plug＆Play Index Register O2Eh-03Fh 2Fh RW Plug＆Play Data Register Plug＆Play
040h-04Fh 40h RW Channel 0 Count
41h RW Channel 1 Count Timer Counter 1
42h RW Channel 2 Count (8254 equivalent)
43h RW Command Register
60h R Keyboard controller Data Input Buffer
60h W Keyboard controller Data Output Buffer Keyboard
Controller
61h RW Port B
62h RW Keyboard controller mailbox Register
64h WO Keyboard controller Command Register
060h-06Fh
64h RO Keyboard Controller Status Register
Keyboard
Controller
070h-07Fh 70h WO RTC/CMOS RAM Address Port and NMI
Mask
71h RW RTC/CMOS RAM Data port
RTC/CMOS RAM
080h-09Fh 80h RW Reserved
81h RW Channel 2
82h RW Channel 3
83h RW Channel 1
84h RW Reserved
DMA Memory
Address
Mapper Page
Register
85h RW Reserved
86h RW Reserved
87h RW Channel 0
88h RW Reserved
89h RW Channel 6
8Ah RW Channel 7
8Bh RW Channel 5
8Ch RW Reserved
8Dh RW Reserved
8Eh RW Reserved
8Fh RW Refresh
92h RW Port 92

CARD-PCI/GX Hardware Manual
Rev.A EPSON 9
I/O Address Register Function
A0h WO Initialization Control Word ICW10A0h-BFh A0h WO Operation Control Word OCW2 Interrupt
Controller 2
A0h WO Operation Control Word OCW3 (82C59Aequivalent)
A0h RO Interrupt Service Resister Interrupt
A0h RO Interrupt Request Resister Controller 2
0A0h-BFh A1h WO Initialization Control Word ICW2 (82C59A
equivalent)
A1h WO Initialization Control Word ICW3
A1h WO Initialization Control Word ICW4
A1h RW Operation Control Word OCW1
A1h RW Interrupt Mask Resister
C0h RW DMA Channel 4 Base and Current
Address
C2h RW DMA Channel 4 Base and Current Word
0C0h-0DFh
C4h RW DMA Channel 5 Base and Current
Address
C6h RW DMA Channel 5 Base and Current Word
C8h RW DMA Channel 6 Base and Current
Address
CAh RW DMA Channel 6 Base and Current Word
CCh RW DMA Channel 7 Base and Current
Address
CEh RW DMA Channel 7 Base and Current Word
D0h W0 Command Register
D0h RO Status Register
D2h WO Request Register
D4h WO Mask Register
D6h WO Mode Register
D8h WO Clear Byte Pointer
DMA
Controller 2
(82C37A
equivalent)
DAh RO Master Clear
DAh WO Temporary Register
DCh WO Clear Mask Register
DEh WO Write all Mask Register
0F0h-0FFh F0h,F1h
WO Mathematical Co-processor Resister
100h-1EFh --- --- Usable with ISA
bus

CARD-PCI/GX Hardware Manual
EPSON Rev.A
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I/O Address Register Function
170h-177h 170h RW Data Register
171h RO Error Register
172h RW Sector Count Hard Disk
Controller
173h RW Sector Number
174h RW Cylinder HIGH
175h RW Cylinder LOW
176h RW SDH Register
177h RO Status Register
177h WO Command Register
1F0h-1F7h 1F0h RW Data Register
1F1h RO Error Register
1F2h RW Sector Count
1F3h RW Sector Number
Hard Disk
Controller
1F4h RW Cylinder HIGH
1F5h RW Cylinder LOW
1F6h RW SDH Register
1F7h RO Status Register
1F7h WO Command Register
1F8h-277h --- --- UsablewithISAbus
278h-27Fh 278h RW LPT2 Data Port
279h RO LPT2 Status Port Parallel Port 2
27Ah RW LPT2 Control
27Bh RW Automatic Address Strobe Register
27Ch RW Automatic Data Strobe Register
27Dh RW Automatic Data Strobe Register
27Eh RW Automatic Data Strobe Register
27Fh RW Automatic Data Strobe Register
280h-2F7h --- --- UsablewithISAbus
2F8h-2FFh 2F8h RO Receiver Buffer
2F8h WO Transmit Holding Buffer Serial Port 2
2F8h RW Divider Latch Least Significant Byte
2F9h RW Divider Latch Most Significant Byte
2F9h RW Interrupt Enable Register
2FAh RO Interrupt Register
2FBh RW Line Controller Register
2FCh RW MODEM Control Register
2FDh RO Status Register
2FEh RO MODEM Status Register
2FFh RW Scratch Register

CARD-PCI/GX Hardware Manual
Rev.A EPSON 11
I/O Address Register Function
300h-377h --- --- UsablewithISAbus
378h-37Fh 378h RW LPT1 Data Port
379h RO LPT1 Status Port Parallel Port 1
37Ah RW LPT1 Control
37Bh RW Automatic Address Strobe Register
37Ch RW Automatic Data Strobe Register
37Dh RW Automatic Data Strobe Register
37Eh RW Automatic Data Strobe Register
37Fh RW Automatic Data Strobe Register
380h-3B3h --- --- UsablewithISAbus
3B4h-3BAh 3B4h RW CRT Controller Index
3B5h RW CRT Controller Data VGA Controller
3BAh W Feature Control (monochrome)
3BAh R Input Status Register
3BBh-3BFh --- --- UsablewithISAbus
3C0h-3CFh 3C0h W Attribute Controller Index/Data
3C1h R Attribute Controller Index/Data VGA Controller
3C2h W Miscellaneous Output
3C2h R Input Status Register
3C3h RW VGA Enable
3C4h RW Sequencer Index
3C5h RW Sequencer Data
3C6h RW Video DAC Pixel Mask,Hidden DAC
Register
3C0h-3CFh 3C7h W Pixel Address Read Mode
3C7h R DAC Status VGA Controller
3C8h RW Pixel Mask Write Mode
3C9h RW Pixel Data
3CAh R Future Control Readback
3CCh R Miscellaneous Output Readback
3CEh RW Graphics Controller Index
3CFh RW Graphics Controller Data
3D0h-3DFh 3D4h RW CRT Controller Index
3D5h RW CRT Controller Data VGA Controller
3DAh W Feature Control (color)
3DAh R Input Status Register
3E0h-3EFh --- --- UsablewithISAbus

CARD-PCI/GX Hardware Manual
EPSON Rev.A
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I/O Address Register Function
3F0h RW Status Register A
3F1h RW Status Register B
3F2h WO Digital Output Register
3F3h RW Tape Drive Register
3F4h RW Main Status Register
3F5h RW Data Register
FDD Controller
3F6h RW Alternate Status, Device Control IDE
3F0h-3F7h
3F7h RO Digital Input Resister
(Shared with Hard Disk Controller) IDE 1 section FDD
3F7h WO Diskette Control Register FDD Controller3F8h-3FFh 3F8h RO Receiver Buffer
3F8h WO Transmit holding Buffer Serial Port 1
3F8h RW Divider Latch Least Significant Byte
3F9h RW Divider Latch Most Significant Byte
3F9h RW Interrupt Enable Register
3FAh RO Interrupt ID Register
3FBh RW Line Control Register
3FCh RW MODEM Control Register
3FDh RO Status Register
3FEh RO MODEM Status Register
3FFh RW Scratch Register

CARD-PCI/GX Hardware Manual
Rev.A EPSON 13
1.6 DMA controller
SCE8720C is provided with 2 DMA controllers (82C37A equivalent) used as follows. With
SCE8720C, DMA is not available from users, as the ISA bus only has limited functions.
Table 1.2 DME controller 1
Channel No. Device
CH0 Not available (cannot be used by user)
CH1 Not available (cannot be used by user)
CH2 Floppy disk
CH3 Not available (cannot be used by user)
Table 1.3 DME controller 2
Channel No. Device
CH4 Cascade connection of controller 1.
CH5 Not available (cannot be used by user)
CH6 Not available (cannot be used by user)
CH7 Not available (cannot be used by user)
Controller 1, including CH0 to CH3, is used for 8-bit data transfer. Up to 64KB block
transfer is possible between 8-bit I/O and 8-bit memory or 16-bit memory.
Controller 2, including CH4 to CH7, is mainly used for 16-bit data transfer, and among
them CH4 is used for cascade connection of controller 1. CH5 to CH7 are not used.
Controller 2, including CH4 to CH7, is mainly used for 16-bit data transfer, and among
them CH4 is used for cascade connection of controller 1. CH5 to CH7 are not used.
Table 1.4 DMA page register
Page register I/O address
DMA channel 0 0087h
DMA channel 1 0083h
DMA channel 2 0081h
DMA channel 3 0082h
DMA channel 5 008Bh
DMA channel 6 0089h
DMA channel 7 008Ah
REFRESH 008Fh

CARD-PCI/GX Hardware Manual
EPSON Rev.A
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1.7 System interrupts
The causes of interrupts on SCE8720C are shown below:
Table 1.5 Causes of interrupts
Level Functions
SMI External system management interrupt
Power management VSA
IRQ Interrupts by interrupt controller
IRQ interrupts are triggered by the 2 interrupt controllers (82C59 equivalent). The causes
of interrupts by interrupt controllers are shown below:
Table 1.6 Levels of interrupts by interrupt controller
Controller 1 Controller 2 Device
IRQ0 Timer out 0
IRQ1 Keyboard
IRQ2 Cascade connection from controller 2
IRQ8 Real time clock
IRQ9 Usable with ISA bus
IRQ10 Serial port (*)
IRQ11 Serial port (*)
IRQ12 Mouse
IRQ13 Co-Processor
IRQ14 HDD
IRQ15 Usable with ISA bus
IRQ3 Serial port 2 (*)
IRQ4 Serial port 1 (*)
IRQ5 Parallel port 2 (*)
IRQ6 FDD
IRQ7 Parallel port 1 (*)
*: SCE8720C has 2 serial ports and 1 parallel port built-in. Serial port interrupts are
selected from IRQ3, 4, 10 or 11, and parallel port interrupts are selected from IRQ5 or 7.
Interrupts not used by the built-in serial or parallel port can then be used with ISA
bus.
Also, when not using HDD, IRQ14 can be used with ISA bus.

CARD-PCI/GX Hardware Manual
Rev.A EPSON 15
1.8 Timer counter
SCE8720C has a 8254-equivalent timer counter and 3 independent timers. Their usage
and inputs are shown below:
Table 1.7 Timer 1 settings
Channel 0 GATE 0 Fixed to ON
System timer CLK IN 0 1.19MHz
CLK OUT 0 Connected to IRQ0 of interrupt controller 1.
Channel 1 GATE 1 Fixed to ON
Refresh request CLK IN 1 1.19MHz
CLK OUT 1 Refresh request
Channel 2 GATE 2 Controlled by I/O port 61h.
Speaker interface CLK IN 2 1.19MHz
CLK OUT 2 Used to drive the speaker interface.