4C24 CPU MANUAL
VERSION 1.5
Copyright 1997 by MESA ELECTRONICS Richmoond, CA. Printed in the United States of
America. All rights reser ved. This document and the data disclosed herein is not to be repr o duced,
used, disclosed in whole or in part to anyone without the written permission of MESA
ELECTRONICS.
Mesa Electronics
4175 Lakesi de Driv e, Suite #100
Rich mond, C A 94806-1950
Tel (510) 223-9272 - Fax (510) 223-9585
E-Mail: tech@mesanet.com - Websi te: www.mes anet.com
4C24 CPU USER'S MA NUA L
TABLE OF CONTENTS
HANDL IN G PR E CAUTIONS
Lithi um cel l 6............................................................................
Static el ectrici ty 6........................................................................
INTRODUCTIO N
General 7................................................................................
CONFIGURATION
General 8................................................................................
Default jumper settings 9................................................................
Watch dog enab le 10.....................................................................
Disk emulator type selection 10..........................................................
Lithium cell enable 10....................................................................
CONNECTORS
Power connector 11......................................................................
Keyboard connector 11..................................................................
Serial port connectors 12.................................................................
Paral lel port conn ector 13................................................................
CPU OPERATION
Power consum ption 15...................................................................
Watch dog tim er 15.......................................................................
Seri al por ts 15............................................................................
Paral lel port 15...........................................................................
Other I /O 15.............................................................................
Setup storage 16.........................................................................
SET4CSIO 16...........................................................................
Seri al f i le d ownlo ad 19...................................................................
Console switching 20....................................................................
Hard drives 21...........................................................................
4C24 CPU USER'S MA NUA L
TABLE OF CONTENTS
DISK EMULATOR OPERATION
General 22...............................................................................
Reliability 22.............................................................................
4C24 Tool C hip 22.......................................................................
Disk emulator initialization 23
INSTALLATIO N
General 24...............................................................................
I/O con nect or orie ntati on 24.............................................................
REFERENCE INFORMATION
Specifications 25.........................................................................
Warranty 26..............................................................................
Schematic di agrams 27...................................................................
...........................................................
4C24 CPU USER'S MA NUA L
4C24 CPU USER'S MA NUA L
HANDLI NG PRECAUTI O NS
LITHIUM CELL
The 4C24 CPU card contains a lithium cell which can create a fire or
explosion hazard if improperly handled.
Do not expose batter y to tem p e r atur e s in exc e ss of 100 degr e e s C e ls ius or
dispose of in fire.
Do not attempt to charge battery or modify battery related circuitry on the
4C24.
Do not shor t circuit battery (take car e not to set the 4 C24 on conduc tive
surface s).
STATIC ELECTRICITY
The CMOS integrated circuits on the 4C24 can be damaged by exposure to electro st at ic
discharges. The following precau tions should be taken when handling t he 4C24 to pr event
possible damage.
A. Leave the 4C24 in i ts antistatic bag until needed.
B. All work should be performed at an antistatic workstation.
C. Ground equipmen t in to which 4C24 wi ll b e in stalled.
D. Ground ha ndli ng personn el wi th conductive bracel et through 1 megohm resistor to
ground.
E. Avoid wearing synthetic fabrics, particularly Nylon.
4C24 CPU USER'S MA NUA L
INTRODUCTION
GENERAL
The 4C24 i s a low power, all CMOS, A T compati b le CPU implemented on the PC/104 bu s. The
4C24 can use vari ous CPU's from 33 MHz 386SX to a 25/50 MHz TI 486SLC2 CPU. A Cy rix 87SLC
math coprocessor is avail able as an option. System memory c an be 1M byte or 4M bytes. A precision
reset circuit, watchdog timer, EEPROM setup stor age, and built in disk emulator make the 4C24
especial ly sui ted to embedded applic ations.
Two dis k emul ator sockets are provided. These sockets can use 5V flash EEPROM or EPROM.
Tot al disk emulator capacity is 1 M byte using flash EE PROM, or 2 M bytes using EPROM. The
emulated drive is bootable and has full compatibility with application and operating system software.
Writi ng to the fl ash di s k i s j ust a standard DOS write, no speci al programs are needed for writi ng or
packing the flash disk. All utilities for using the disk emulator are provided with the 4C24.
The 4C24 BIOS EPROM can use fl ash memory to all ow field upgrades without physi cal access to
the 4C24 card. The 4C24 BIOS is normally 64K bytes but can be extended to 128K bytes to
accommodate Datalight ROM DOS or other built in operating systems.
On card 4C24 I/O includes two RS-232 serial ports, a bi-directional parallel port , and an AT
compatibl e keyboard port. The serial interf ace chips used on the 4C24 are compatible wi th 16C550A
UARTs, with 16 character receive an d transmit F IFOs.
All standard AT logic is provided by the 4C24, including 2 interrupt controllers, 2 DMA
controllers, keyb oard controller, and battery backed clock. Configurati on storage is provided by an
EEPROM, which i s much more resistant to inadvertent damage that the CMOS configuration storage
in a standard AT. The BIOS autodetects IDE hard drive parameters and floppy drive types, so that
setup information need not be chan ged when changing dri ves.
4C24 power consumption is 4W maximum with the 486SLC CPU and 3W maximum with the
386SX. CPU clock and numeric coprocesso r clock can be slowed to conser ve power when the full
CPU speed is n ot requi red. The RS-232 i nterface power is gen erated on card, so that only +5V power
is required by the 4C24
Pa g e 7
4C24 CPU USER'S MA NUA L
CONFIGURATION
GENERAL
The 4C24 has three user settable jumpers. One of the jumpers is used to enable or disable the
watchdog, one is used f or setting the dis k emulator chip type, and the third is used for disconnectin g
the li thi um cel l. When the words "up", and "down" are used i t i s assum ed that the 4C24 CPU card is
oriented with i ts bus connectors J1 and J2 at the bottom edge of the card (nearest the person doin g the
configuration).
DEFAULT JUMPER SETTINGS
Factory default 4C24 jum pering i s as f ollows :
FUNCTION JUMPER SETTING
WatchDog enable W1 UP - Watchdog enabled
Disk emulator U14 t ype W2 UP - Flash EEPROM
Lithium c ell co n nect W8 D isa bled
Pa g e 8
4C24 CPU USER'S MA NUA L
CONFIGURATION
DEFAULT JUMP ER SETTINGS
Pa g e 9
4C24 CPU USER'S MA NUA L
CONFIGURATION
WATCHDOG ENABLE
The 4C24 has a hardware watchdog t imer that will reset the CPU unless 'fed' perio dically by
system software. In a DOS environment, the BIOS performs this service when it services the
hardware tic interrupt. When o ther operating systems are used, (Linux,PSOS,QNX etc) it may be
necessary to disable the watchdog. Watchdog enabl e is controll ed b y j umper W1. When W 1 is in the
up position, the watchdog is enabled. When W1 is in the down position, the watchdog is disabled.
DISK EMULATOR TYPE SELECTION
The 4C24 has two 32 pin PLCC sockets available disk emulator use. These sockets are the two
upper sockets on the 4C24 (U11 and U14). The disk emulator can use EPROM or 5V flash
EEPROM. Each socket can be configured independently. This allows the creation of dual drive (C:
and D:) disk emulator systems using different memory technologies. For example. A system could be
configured wi th a 512K EPROM disk for program storage, and a 128K fl ash EEPROM disk for data
collection. I f both so cket s use the same chip type, t hey can be combined into a single, larger d isk
emulator.
The 4C24 disk emulator hardware needs to be configured to match the memory type used. W2
selects the mem ory type for socket U14 (di sk 1). The jumper needs to be set to the up position for fl ash
EEPROM and the down positi on for EPROM > 512K.
For more information on disk emulator usage, see the CPU operation section of the manual.
You must use a PLCC chip extraction tool when removing disk chips from the 4C24.
Improvised tools such as bent paper clips etc. can damage the PLCC socket, the chip and/or the
4C24 circuit card. Such damage will void the 4C24 warranty
.
LITHIUM CELL ENABLE
The 4C24 has Lit hium coin cell that powers the clock/calendar and the CMOS setup stor age
RAM. If jumper W8 is removed or placed on one pin, the Lithium cell will be disconnected. The 4C24
is sh i pped with the cell di sconn ected, so you must i nstal l W8 on both pins in order to use the battery
backed clock/calendar.
The 4C24 BIOS d o es not use the CMOS set up RAM, so it is possible to run the 4C24 with no
Lithium cell if desired.
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4C24 CPU USER'S MA NUA L
CONNECTORS
POWER CONNECTOR
The 4C24 power connector (P2) is a 4 pin, single row, .1" header. The suggested mating
connector is an AMP MTA type connector 641190-4 (non-feedthrough) or 641198-4 (feedthrough).
These are both gold plated type connectors. Power pin arrangement i s +5V, gnd, gnd, +5V. Thi s pinout is compatible with newer (+5V only ) 3.5 inch fl oppy drives.
Since the power connector on the 4C24 may power the whole PC104 stack, it is suggested that
only gol d plated connectors be used. Tin pl ated connectors have a pronounced tendency to fai l over
time vi a i ncreased contact resistance when operated at anywhere ne ar thei r rated current.
Power connector pinout is as f ollows :
PIN SIGNAL CURRENT RATING
1 +5V 1A
2 GND 1A
3 GND 1A
4 +5V 1A
The current ratings above m ean that the total +5V current needs to be l imi ted to 2A.
KEYBOARD CONNECTOR
P4 is the AT keyb oard, reset-in and speaker connector. P4 is a 10 pi n dual row 2mm h eader. The
suggested mating conn ector is Suyi n20043-10G2 or 3M 152210-100-GG. Thi s is an IDC (fl at cabl e)
type connector. A keyboard adapter cabl e is av ailab le f rom MESA (The 4C24KBADPT).
An external reset switch i nput and speaker output are also availabl e on P4. The reset circuit works
by grounding the /RESIN signal .
The speaker output is intended to drive hi gh i mpedance speakers (40 ohms or more) . Eight Ohm
speaker s will be to o q uiet for mo st ap plica tio ns . T he speaker common is +5V. An exter nal PNP
transistor can b e used to driv e an eight Ohm speaker to obnoxious volume level s i f requi red.
Page 11
KEYBOARD CONNECTOR
Keyboard connector pin-out is as follows:
PIN SIGNAL FUNCTION
1 SPKOUT Speaker out
2 SPKVCC Speaker common (+5V)
3 /RESIN Reset in
4 /RESINGND Reset common
5 MSCLK Mouse cl ock (unsupported)
6 KBCLK Keyboard clock
4C24 CPU USER'S MA NUA L
CONNECTORS
7 KBDAT Keyboard data
8 MSDAT Mouse data (unsupported)
9 KBGND Keyboar d g r ound
10 KBVCC Keyboard +5V
If a keyboard is not used, i t is possible to speed up 4C24 boot-up by grounding KBCLK. T his
informs the BIOS that no keyboard is present. This avoids the 2-3 second wait for keyboard response
to the reset command.
SERIAL PORT CONNECTOR
P2 and P3 are the serial port connectors. P2 and P3 are 10 pin, dual row .1" headers. The
suggested mating connector is AMP PN 499934-1. This i s an IDC (flat cable ) type connector.
When t he flat cable from P2 or P3 is terminated with a male 9 pin D type connector (suggested
connector AMP 747306-4), the 9 pin conn ector wil l have a si m i l ar pi n-out to the AT type 9 pin serial
port. The pin 10 wire must be stripped from the cable before installing the D connector. A one foot
long serial port adapter cable is available from MESA .
The default BIOS port mapping selects P2 as COM1 and P3 as COM2.
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4C24 CPU USER'S MA NUA L
SERIAL PORT CONNECTOR
Serial port connector pin -out is as fol lows:
HEADER PIN DSUB PIN SIGNAL FUNCTION
1 1 DCD Handshake i n
2 6 DSR Handshake i n
32 RXD Data in
4 7 RTS Handshake out
53 TXD Data out
CONNECTORS
6 8 CTS Handshake i n
7 4 DTR Handshake out
8 9 RI Handshake i n
9 5 GND Signal ground
10 NC +5V +5V user po w er or key
PARALLEL PORT CONNECTOR
The 4C24 has a parall el printer port. The connector for the parall el port uses a 26 pin, 2mm header
to save space. An adapter widget is avai l ab l e f rom MESA that converts between the 1mm cabl e and
standard .050 flat cable. The 26 pin connector arrangement is such that when terminated with a
stan dard D B 25 con nect or, the p aral lel port pi nout m atch es the IBM sta ndard pin out
Page 13
4C24 CPU USER'S MA NUA L
PARALLEL PORT
Parallel port connector pin-out is as follows:
HEADER PIN DSUB PIN SIGNAL FUNCTION
1 1 /PSTB Strobe (out)
2 14 /PAFD Auto LF ( out )
3 2 /PD0 Data 0
4 15 /PERROR Printer err or (in)
53 PD1 Data 1
6 16 /PINIT Reset pri nter (out)
CONNECTORS
74 PD2 Data 2
8 17 /PSLIN Select printer (out)
95 PD3 Data 3
10 18 GND Ground
11 6 PD4 Data 4
12 19 GND Ground
13 7 PD5 Data 5
14 20 GND Ground
15 8 PD6 Data 6
16 21 GND Ground
17 9 PD7 Data 7
18 22 GND Ground
19 10 /PACK Pri nter Ack (in)
20 23 GND Ground
21 11 PBUSY D ata in (in)
22 24 GND Ground
23 12 PPE Paper out (in)
24 25 GND Ground
25 13 PSLCT Pri nter selected (in)
26 NC +5V Key
Page 14
4C24 CPU USER'S MA NUA L
CPU OPERATION
POWER CONSUMPTION
The 4C24 is an all CMOS CPU, so overall power consumpti on is typi cally l ess than 3 watts (about
400 mA). If the lo west po wer consumption is necessary, t he CPU c lock ca n be slowed when not
active. This can reduce the CPU power to less than 150 mA. It is the responsibility of the application
program to execute the slow CPU instructions when idl e.
4C24's with Cyrix or TI 486SLC 's can be put into a low power mode by sim ply haltin g the CPU.
The B IOS keyboard i nput (Int 16 fu ncti on 0) routine does this automatic all y, so a ppli cation program s
that cal l thi s fun ction when wai ting f or i nput will use minim um power.
If the absolute lowest power consumption i s required, Mesa can supply a ve rsion of the 4C24 that
uses a lower power PAL. Please contact MESA for m ore informati on on this l ow power CPU versi on.
WATCHDOG TIMER
The 4C24 is intended mainly for embedded system applications where there is no one to hit the
reset switch should something go awry. To prevent a crashed or otherwise hung system from
remai nin g so indefi ni tely , the 4C24 is provi ded with a bui lt i n watchdog tim er that will reset the 4C24
if not 'fed' regularly. The time-out period of this counter is 1.6 seconds. The default INT 1C (user tic
clock ) t ask 'feeds' the wat c hdo g.
than these time periods or the watchdog may bite!
User sof tware must be c ar ef u l not to disabl e interrupts f or more
SERIAL PORTS
The serial ports on the 4C24 are compatibl e with 16C550A type UARTS . These UARTS have 16
byte receive and transmit FIFO's. The serial ports can be setup by the BIOS to be COM1 and COM2
or COM3 andCOM4 (vide in fra). Defaul t setup is COM1 and COM2 (0x3F8 and 0x2F8).
PARALLEL PORT
The 4C24 parallel port is capable of bidirectional operation. The parallel port I/O address can be
set to be at the LPT1, LPT2, or LPT3 locati ons. Defaul t port locati on is 0x278.
OTHER I/O
The 4C24 uses the game port chip select in the 82C7XX multi-I/O chip for accessing on card I/O
ports. These ports control the setup EE PR OM and t he disk emul ator hardware. The I /O por ts are
located at 200H and 201H.
You must make sure that no external I/O cards overlap this area
.
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4C24 CPU USER'S MA NUA L
CPU OPERATION
SETUP STORAGE
Many 4C24 options can be saved i n the serial EEPROM on the 4C24 card. These options i nclude:
ini tial baud rate, COM port locations, parall el port location, etc. These parameters can be set with the
provided utility SET4C24.EXE
SET4C24 reads a text fil e of setup options, and programs these i nto the 4C24's EEPROM. These
setup files have a default extension of .CF. SET4C24 and a numb er of configuration f iles are l ocated in
the UTILS directory of the 4C24 di stribution f l oppy. SET4C24 is invoked wi th the conf i guration fi l e
name as a parameter:
SET4C24 4C24.CF
Would conf igure the 4C24 wi th the EEPROM settings in the 4C24.CF confi guration fi le.
SET4C24 has three command l i ne swi tches : /D, /N and /Q. These comm and l i ne s witches f ol l ow
the fil e n ame. The /D option causes the 4C24 EEPROM to be initi al i zed to it's default configuration.
When the /D option is used, no file name is needed. The /N option causes the configuration file t o
modify the defa u lt c onfig ur at ion, and st o r e t he r esult into the EEPROM. I f /N is not specified, all
options not specifi call y changed in the confi guration fi le wil l remain at their previous settings.
As l ong as the /N or /D switches are not used, configuration fi les loaded wi th SET4C24 only affect
the options specif ied in the file. Thi s m akes it possible to separate the confi guration fi les in to pieces
that only affect a ce rtain aspect o f 4C24 operat ion. Note t hat E E PROM sett ings do not t ake effect
until the 4C24 is reset.
For more information on setup options you should list the 4C24.CF fil e i n the UT ILS directory of
the distribution disk. This file has all of the available setup op tions specified. Normal usage of the
4C24.CF fil e is to leave al l of the opti ons in the file, but comm en t out the undesired options. options
can be comm ented out by precedi ng the li ne wi th a semicol on.
SET4CSIO
The serial and paral lel port settings c an also be ch anged dyn amical ly with the i ncluded setup utility
SET4CSI O.EX E. These sett ing are volatile, and will rever t t o t he defau lt sett ings at p ower up or
hardware reset. The setup utility can be run as part of your AUTOEXEC.BAT file.
SET4CSIO is invoked wi th one comm and li ne param eter, a configuration file nam e:
SET4CSIO COM3COM4.CFG
T he c o m ma n d lin e p a r a m e t e r is th e name o f th e c onf ig u r a t ion file . T h e c o n fig u r a tion file is a n
ASCII file containing the config urat ion parameters. T he UTILS director y of the 4C24 distribution
disk has two example configuration files, COM3COM4. CFG and STAN DARD.CFG . Yo u s hould
use these fi les as a starting point to creating your own confi guration fi les.
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4C24 CPU USER'S MA NUA L
CPU OPERATION
SET4CSIO
The format of the configuration fi le i s very simple : each line of the configuration fil e consists of a
parameter name followed by a parameter value. If a parameter name is not specified in the
configuration file, that parameter will be set to the default value shown in the f ollowing table.
The parameter names, parameter values, and default parameter values are as follows:
PARAMETER PARAMETER VALUES DEFAULT
PP-ADDRESS OFF 278
278
378
3BC
The PP-ADDRESS parameter selects the location of the parallel port. The parallel port can be
dis abled i f desired by setting the parameter to 'OF F'
PP-MODE UNI-DIRECT UNI-DIRECT
BI-DIRECT
The PP-MODE parameter sets the operational mode of the parallel port. The default unidirectional mode is the standard printer port mode. When set to the bi- directional mode, bit 5 of the
printer contro l port determines the sig nal direction on the printer dat a lines. A low on bit 5 sets the
l in es to the outp ut dir ecti on, a h igh on bi t 5 sets th e data l in es to th e in put di recti on.
COM3&4-ADDRESS 338-238 338-238
3E8-2E8
2E8-2E0
220-228
The COM3&4-ADDRESS parameter all ows selection of the l ocations of serial ports COM3 and
COM4. These port addresses will not be used unless the primary or secondary serial port has COM3
or COM4 selected as an address.
Note that 3E8 and 2E8 are the most commonly used l ocations f or COM3 and COM4
Page 17
4C24 CPU USER'S MA NUA L
CPU OPERATION
SET4CSIO
PARAMETER PARAMETER VALUES DEFAULT
PRIMSER-ADDRESS 3F8 3F8
2F8
COM3
COM4
Sets the address of the pri mary serial port (The port connected to P2). If set to COM3 or COM4,
the address is determined by the COM3&4-ADDRESS parameter.
SECSER-ADDRESS 2F8 2F8
3F8
COM3
COM4
Sets the address of the secondary serial port (T he port connected to P3). If set to COM3 or
COM4, the address i s determi ned by the COM3&4-ADDRESS parameter.
PRIMSER-ENABLE YES YES
NO
This parameter enables or disables the primary serial port.
SECSER-ENABLE YES YES
NO
This p arameter enables or dis ables the secondary serial port.
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4C24 CPU USER'S MA NUA L
CPU OPERATION
SERIAL FILE DOWNLOAD
To allow transferring of application programs to the 4C24, which may not have a floppy driv e or
other means of transferring programs, a set of utility programs are provided. They are cal led SEND
and RECV.
SEND and RECV co mprise a very simple file download ut ility set. When the 4C24 is supplied
with ROM-DOS, RECV is normal ly suppli ed buil t into the BIOS ROM as part of the ROM drive (C:).
The fi rst requi rement f or SEND and RECV to work is the proper cab le. This c able has onl y three
wires, and is a 'data only null modem' cable. Assuming that your host machines serial port is a 9 pin
male (AT pinout) type, and that the 4C24 has it's seri al port adaptor cable, the c able would h ave 9 pin
female connectors at both ends and the following connections:
9 pin 9 pin
5 -------- 5 ( ground )
2 -------- 3 ( data <- )
3 -------- 2 ( data -> )
If your host machi n e has a 25 pin serial connector, the cable needs a female 25 pin connector on
the host end and a female 9 pin connector on the client end. This cable must have the following
conne ctions:
25 pin 9 pin
7 -------- 5 ( ground )
2 -------- 2 ( data -> )
3 -------- 3 ( data <- )
If you do not wish to make a cable, a down load adaptor cable is avail able from MESA. The part
name i s DW LDADPT. This i s a five foot cable with a 10 pi n h eader on one end (the 4C24 end) and a
female 9 pin D connector at the other end. The 9 pin D connector connects to the host system's serial
port.
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4C24 CPU USER'S MA NUA L
CPU OPERATION
SERIAL FILE DOWNLOAD
SEND runs on a host machi n e. This h ost machi n e must be a PC wi th a standard COMX RS-232
serial port available.
SEND is invoked this way:
SEND PPP [BR]
PPP is the hexadecimal port address of the serial port on the host machine (3F8 = COM1, 2F8 =
COM2, 3E8 = COM3, and 2E8 = COM4). BR is an optional baud rate parameter . If BR is not
supplied, se nd uses 9600 baud. For example SEND 2F8 38400 would send files through COM2 at
38400 baud.
Once SEND is running on the host machine, RECV is run on the client CPU card to download
files.
RECV is invoked this way:
RECV RFN LFN [BR] [Q]
RFN is the remote file name (the source file) which is relative to the path where send was
launched. LFN is the local file name (the target file). The Q par amet er causes SE N D t o be aborted
when the file transfer is complete. BR is an optional baud rate parameter. If BR is not suppl ied, RECV
uses 9600 baud. For example RECV FOO GOO 38400 Q woul d get the re mote fil e F OO, write it to
the local fil e GOO, and abort SEND when done. All data transf ers would be done at 38400 baud.
The remote file name can include a drive and path, allowing access to different directo ries,
network drives etc.
If y ou set the baud rates on the command l ine, the SEND baud rate must match the RECV baud
rate. Maximum practical baud rate is 115200 baud. You may not be able to use the maximum baud
rate, depending on your host CPU speed, serial port characteristics, interconnect cable etc. (Your
mi le age may vary ).
CONSOLE SWITCHING
To simplfy system initiali zation, the 4C24 will use the COM1 serial port as the console if no vi deo
adap tor is fou nd at system startup. T he default baud r a te is 9600. This console re-direction can be
dis abled i n the EEPROM setup if desi red.
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4C24 CPU USER'S MA NUA L
CPU OPERATION
HARD DRIVES
The 4C24 BIOS supports IDE type hard drives. You need to supply an external IDE controller
card (our 4I26 for exampl e) to use the 4C24 with an IDE drive. The 4C24 BIOS reads the hard drive
parameters directly from the IDE drive. This means that no drive parameter information is stored on
the 4C24 card. This makes i t much easier to install and change hard drives. It is especi all y convenien t
when using ATA (PCMCIA format) removeable drives.
Hard drives are added to the 4C24 drive l i st after local f lash drives. For example if you have a two
drive flash disk system, the flash drives would be assigned letters C: and D: and the hard drive would
become E:
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4C24 CPU USER'S MA NUA L
DISK EMULATOR OPERATION
GENERAL
The 4C24 has a bui lt in n onvolatile di sk emul ator with a capaci ty of up to 2M bytes usin g EPROM
or 1 M byte using flash EEPROM.
Two 32 pin sockets on the 4C24 can be used for di sk emulator memory ch ips. These two chi ps can
be used together as a sin gle drive, or each chi p can be confi gured as an i n dependent drive. W hen two
drives are configured, the chips can be of different types. For example, a configuration with EPROM
for program storage and fl ash EEPROM for data loggi ng is a popular arrangement.
When us ing t he bu ilt in disk e mulat o r, t he d isk t ype c o nfigur at io n jumper s mus t be first set t o
match the type of disk emulator chip(s) used. (See the HARDWARE CONFIGURATION section of
thi s m an ual .)
The 4C24 disk emulator is viewed as a hard disk by system s oftware. This means that the first
emulated drive will be drive C: , and the next emulated drive will be drive D:.
RELIABILITY
In an em bedded system environment where a system that won't boot is basicall y a f ailed system, it
is import ant to unde rst and so me charac ter istics of the DOS o pera ting syste m that applies to disk
access. When DOS writes a file, it writes t o the FAT and directory areas of the drive (emulated or
real).
If there is any chance that a system can be reset or power can fail when writing to this disk, all
information on the disk could become inaccessible,
The reason is that when DOS writes to a directory or FAT area it alw ay s wri tes a ful l sector, not
just the directory or FAT entry required. If the sector write is not completed, the sector with the
directory or FAT entry that was being written will have an invalid CRC. This can affect any fi le on the
drive!
In appl ic ations th at do frequent di sk wri tes, there are two possib l e soluti ons to this probl em. The
first solution is to disable emulated disk CRC checking. This will mak e a par tia lly r e w rit te n sect or
readable by the operating system. This will only impr ov e th e odds of surviving a power off or reset
during a file wr it e, not to tally eliminate the problem. Turning off CRC's will also mask po ssible
hardware pro blems, so is not genera lly sug gested. The second solution is to configure a two drive
system, with a drive (usuall y C :) used as the software driv e, and the other drive (usually D:) used as
the data drive. Any files writes during normal operation would be done to the D: drive. If any problem
occurs on the D: drive, software on the C: drive can attempt to recover the data, and then re-ini tiali ze
the D: drive.
not
just the file that was being written.
4C24 TOOL CHIP
An EPROM disk chip preloaded with a set of basic 4C24 utilities is available fr om MESA at a
nomi nal charge. If y ou do not have a PC-104 floppy controller, it is suggested that you purchase this
chi p to si mpli fy fi rst time 4C24 setup and disk i niti ali zation.
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4C24 CPU USER'S MA NUA L
DISK EMULATOR OPERATION
DISK EMULATOR INITIALIZATION
Before using the disk emulator, it needs to be initialized so that the 4C24 BIOS knows the size,
chip type, and organization of the disk emulator.
This initialization is done with INITRAMD.EXE. INITRAMD.EXE is supplied in the DISK
subdirecto r y of the 4C24 distribution disk. If INITRAMD is run with a /L parameter, it will list the
types o f disk e mulato r ch ips supporte d by the 4C24 BIOS. Each type of disk emulat or chip has a
corresponding Devi cetype number.
To initialize a disk emulator, you invoke INITRAMD as follows:
INITRAMD /CStartChip /NNumberOfChips /DDeviceType [/F[O | D]]
Where Start Chip is 0 or 1, NumberOfChips is 1 or 2 and DeviceType is a number listed by the
INITRAMD /L com mand.
The /F p arameter in vokes a bui lt-i n FDISK and F ORMAT option. The /F option can opti onall y be
foll owed by D or O. This option selects standard DOS format (D) or a speciall y optimi sed form at for
use with Datali ght ROM-DOS (O). The ROM-DOS format uses 512 by te al location units and saves
space in small drives.
behavior will result!
On the 4C24, there are 2 avail ab le sockets, the upper socket (U11) and the lower socket (U14).
INITRAMD numbers these sockets such that the upper socket is socket 0 and the lower socket is
socket 1.
If you wanted to ini tialize a 2 socket disk em ulator using device ty pe 1, the INITRAMD comm and
would b e:
Do not use the O option with stan dard DOS or unpredictable file system
INITRAMD /C0 /N2 /D1 /FD
( Initiali ze disk starting at socket 0, using 2 sockets and device type 1 - DOS format)
It is a ls o p os s ible to initia lize tw o in d ep e nde nt d is k e m u la t or s b y in v o k in g I N IT RAM D tw ic e ,
once per socket:
INITRAMD /C0 /N1 /D3 /FO
( Initiali ze disk starting at socket 0, using 1 sockets and device type 3 - ROM-DOS format)
INITRAMD /C1 /N1 /D5 /FO
( Initiali ze disk starting at socket 1, using 1 sockets and device type 5 - ROM-DOS format)
Once the disk em ulator has been i niti ali zed, the 4C24 needs to be reset before the new disk will be
recognized by the operating system.
You should not normal ly need to run FDISK or FORMAT as long as y ou specify the /F parameter
when initializing a drive.
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4C24 CPU USER'S MA NUA L
INSTALLATION
GENERAL
When the 4C24 h as been properly conf igured for its appl ication, it can be inse rted in to a PC/104
st ack . Th e st and offs shou ld t hen be tigh te ned t o secure the 4C24 in its place. When the 4C24 is
secured in the stack the I/O connectors headers can be plugged in from the si des.
I/O CONNECTOR ORIENTATION
The serial port connectors on the 4C24 are 10 pi n, right angle .1" headers. Pin 10 of the serial port
connector can be cut, and a keying plug installed in the cable mount header if desired to prevent
reverse installation of the serial cabl es. If more positive polarization is desi red on the 10 pin headers,
center polari zed IDC header connectors should be used. These connectors wi ll n ot ful ly mate with the
pins on the 4C24 i f i n stall ed backwards. A suggested center polarized 10 pi n IDC header is AMP PN
499934-1.
All connectors on the 4C24 have their pin one ends marked with a white square on the circuit card.
This corresponds with the red stripe on typi cal f lat cable assem blies.
Page 24
SPECIFICA TIONS
POWER S U PPLY
Voltage 4.5 5.5 V
Supply cur rent (full speed 386SX) --- 500 mA
Supply cur rent (sleep mode386SX) --- 150 mA
Supply cur rent (full speed 486SLC) --- 750 mA
Supply cur rent (sleep mode 486SLC) --- 150 mA
BUS LO AD ING A ND DR IVE:
4C24 CPU USER'S MA NUA L
REFERENCE INFORMATION
MIN MAX UNIT
Input capaci tance --- 20 pF
Input leakage current --- 5 uA
Output drive capabilit y --- 150 pF
Output sink current 6 --- mA
ENVIRONMENTAL:
Operating temperat ur e range
o
-I versi on -40 +85
-C version 0 +70
C
o
C
Relative humidity 0 90 Percent
Non-condensing
Page 25
4C24 CPU USER'S MA NUA L
REFERENCE INFORMATION
WARRANTY
Mesa Electronics warrants the products it manufactures to be free effects in material and
workmanship under normal use and service for the period of 2 years from date o f purchase. This
warranty shall not apply to products which have been subject to misuse, neglect, accident, or
abnormal conditions of operation.
In the event of fa ilure of a product covered by this warranty, Mesa Ele ctr onics, will re p a ir an y
product returned to Mesa Electr o nics within 2 years of original purchase, provided the warranto r 's
examination discloses t o its satisfaction that the pro duct was defective. The warrantor may at its
option, repl ace the product in l ieu of repai r.
Wi th regard to any product returned with in 2 ye ars of purchase , sai d repairs or repla cement will be
made without charge. If the failure has been caused by misuse, neglect, accident, or abnormal
conditions of operation, repairs will be billed at a nominal cost.
THE FOREGOING WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES,
EXPRESS OR IMPLIED. INCLUDING BUT NOT LIMITED TO ANY IMPLIED
WARRANTY OF MERCHANTABILITY, FITNESS, OR ADEQUACY FOR ANY
PARTICULAR PURPOSE OR USE. MESA ELECTRONICS SHALL NOT BE LIABLE FOR
ANY SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER IN
CONTRACT, TORT, OR OTHERWISE.
If any failure occurs, the following steps should be taken:
1. No tify Mesa Electro nics, giving full details of the difficulty. On receipt of this information,
service data, or shipping instructions will be forwarded to you.
2. On receipt of the shipping instructions, forward the product, in its original protective
packaging, transportation prepaid to Mesa Electronics. Repairs will be made at Mesa Electronics and
the product returned transportation prepai d.
Page 26
4C24 CPU USER'S MA NUA L
REFERENCE INFORMATION
SCHEMATIC DIAGRAMS
Page 27
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