Advantech ADAM-4500 User manual

ADAM-4500
PC-based Communication
Controller
User's ManualCopyright
Notice
This document is copyrighted, 1997, by Advantech Co., Ltd. All rights are reserved. Advantech Co., Ltd.
reserves the right to make improvements to the products described in this manual at any time without
notice.
No part of this manual may be reproduced, copied, translated or transmitted in any form or by any means
without the prior written permission of Advantech Co., Ltd. Information provided in this manual is
intended to be accurate and reliable. However, Advantech Co., Ltd. assumes no responsibility for its use,
nor for any infringements upon the rights of third parties which may result from its use.
Acknowledgments
ADAM is a trademark of Advantech Co., Ltd.
IBM and PC are trademarks of International Business Machines Corporation.
Part No. 2050500110 1st Edition
Printed in Taiwan July 1997

Table of Contents
Chapter 1 General Information 1
1.1 Introduction 1
1.2 Features 1
1.3 Specifications 2
1.4 System Diagram 3
Chapter 2 Installation Guidelines 5
2.1 System Requirements to Setup ADAM-4500 5
2.2 Steps to Successfully Setup the System 5
Step 1: Review the requirements 5
Step 2: Wiring the power cables and download cable 5
Step 3: Run utility software in host computer 6
Step 4: Power on ADAM-4500 8
2.3 Jumper Setting 8
COM1 Port Setting 9
Watchdog Timer Setting 9
Reset Function Setting 9
2.4 Communication Wiring 9
RS-232 Connection 9
RS-485 Connection 10
Chapter 3 Programming and Downloading 11
3.1 Programming 11
Mini BIOS functions 11
Converting Program Codes 11
Other limitations 12
Programming the Watchdog timer 12
Interrupt types 13
Memory Mapping 13
3.2 Downloading and transferring 14
Install Utility Software on Host PC 14
Preparing the ALLFILE directory 14
Downloading into flash ROM 14
Transferring files to SRAM 16
3.3 Steps to Building a Successful Application 16
Step 1:Write and simulate control logic on a PC 16
Step 2:Connect the cables 16
Step 3:Convert and download codes to flash ROM 17
Step 4:Power on ADAM-4500 to complete the application 17
Chapter 4 Function Library 18
Appendix A Register Structure 30
Appendix B Safety Instructions 32

Chapter 1 General Information
1.1 Introduction
The ADAM-4500 is a fully functional standalone controller, designed for industrial automation and control,
enclosed in a small package. It provides an ideal means of producing an IBM PC compatible hardware
platform.
Emulating Open PC environments
The module is much like a compact computer, and includes an 80188 CPU, 256 KB Flash ROM, 256 KB
SRAM, COM1, COM2, and a program download port. Its built-in ROM-DOS is an MS-DOS equivalent
operating system, which provides all of the basic functions of MS-DOS except for BIOS. A user can run
standard PC software and application programs, written in high level languages such as C or C++, within
the ROM-DOS environment. Moreover, the module also provides free ROM memory for application
downloading and free RAM memory for application operation.
Built-in RS-232/RS-485 Communication Ports
The ADAM-4500 has two communication ports to let the controller easily communicate with the other
devices in your application. The COM1 port can be configured as an RS-232 or an RS-485
communication interface via the jumper setting. The COM2 port is dedicated as an RS-485 port. This
unique design makes the controller suitable for use in a variety of applications.
Built-in Real-time Clock and Watchdog Timer
The controller also includes a real-time clock and a watchdog timer function. The real-time clock ensures
time recording while events occur. The watchdog timer is designed to automatically reset the
microprocessor when the system fails. This feature greatly reduces the level of maintenance required and
makes the ADAM-4500 ideal for use in applications that require a high level of system stability.
1.2 Features
•Built-in boot ROM-DOS to run PC programs
•Free ROM/RAM memory for user's applications
•2-wire, multi-drop RS-485 networking
•Communication speed up to 115.2 Kbps
•RS-232/RS-485 modes (jumper selectable)
•Automatic data flow control in RS-485 mode
•Built-in real-time clock and watchdog timer
•Easy mounting on a DIN-rail or panel
•Program download cable and utility included
1.3 Specifications
System
•CPU: 80188-40
•Flash ROM: 256 KB (170 KB free memory for users)
•Operating system: Boot ROM-DOS
•SRAM: 256 KB ( 234 KB free memory for users)
•Timer BIOS: Yes
•Real-time clock: Yes
•Watchdog timer: Yes
•COM1: RS-232/RS-485
•COM2: RS-485
•Program download port (RS-232): Tx, Rx, GND

RS-232 Interface
•Signals: TxD, RxD, RTS, CTS, DTR, DSR, DCD, RI, GND
•Mode: Asynchronous full duplex, point to point
•Connector: DB-9 pin
•Transmission speed: up to 115.2 Kbps
•Max transmission distance: 50 feet (15.2 m)
RS-485 Interface
•Signals: DATA+, DATA-
•Mode: Half-duplex, multi-drop
•Connector: Plug-in terminal block
•Transmission speed: up to 115.2 Kbps
•Max transmission distance: 1220 m (4000 feet)
Power
•Unregulated +10 to +30 VDC
•Protected against power reversal
•Power consumption: 2.0 W
Mechanical
•Case: ABS with captive mounting hardware
•Plug-in screw terminal block:
Accepts 0.5 mm2to 2.5 mm2, 1 - #12 or 2 - #14 to #22 AWG
Environment
•Operating temperature: -10 to 70°C (14 to 158°F)
•Storage temperature: -25 to 70°C (-13 to 158°F)
•Humidity: 5 to 95 %, non-condensing

1.4 System Diagram
ADAM-4500
Figure 1-1: ADAM-4500 Diagram

Function Block Diagram
SRAM
FLASH ROM
RTC
WDT&Reset
16 Bit
up
Power
Converter
COM#1
UART
COM#2
UART
RS-485
Tranceiver
RS232/485
Tranceiver
Programming
Port
Tranceiver
GND
+5V
+5V
GND
+10V to 30Vdc
Figure 1-2: ADAM-4500 Function Block Diagram
Chapter 2 Installation Guidelines
This chapter provides guidelines to set up and install the ADAM-4500 communication controller. A
simplified hookup scheme is provided that lets you configure a successful system off-line before
implementing it in your application.
2.1 System Requirements to Setup ADAM-4500
The following list gives an overview of what is needed to setup, install and configure an ADAM-4500
system.
•ADAM-4500 module
•An IBM PC/AT compatible computer that can download programs with an RS-232 port.
•Power supply for the ADAM-4500 (+10 to + 30 VDC)
•ADAM-4500 download utility software
•Download cable (RS-232 interface)
Host computer
Any computer that is IBM PC/AT compatible which can run and write programs in an MS-DOS
environment, and provides an RS-232 communication port to allow users to download programs into the
ADAM-4500, can function as the host computer.

Power supply
For ease of use in industrial environments, the ADAM-4500 will accept industry standard +24 VDC
unregulated power. The ADAM-4500 was designed to operate using any power supply voltage between
+10 and +30 VDC. Power ripples must be limited to 5 V peak to peak while the voltage in all cases must
be maintained between +10 and +30 VDC.
Utility software
A disk containing menu-driven utility software is provided with ADAM-4500 to help users to download
programs to the ADAM-4500. The ADAM-4500 utility software is executed in an MS-DOS or compatible
environment.
Download cable
A customized download cable is included. A user can connect it between the COM port of a host
computer and the download port of the ADAM-4500 for downloading programs.
2.2 Steps to Successfully Setup the System
Step 1: Review the requirements
Before you power on the ADAM-4500, make sure you have a host computer, a power supply, and the
utility software and download cable.
Step 2: Wiring the power cables and download cable
Connect the power cable between the power supply and the ADAM-4500. Make sure the power source is
between +10 and +30 VDC.
Figure 2-1: Power Supply Connections
We advise use of the following standard colors (as indicated on the ADAM-4500) for the power cables:
+Vs (R) Red
GND (B) Black
Connect the download cable between the host computer and the ADAM-4500. A customized download
cable is provided with the ADAM-4500, which includes a DB-9 pin connector for the connection to the
host computer, and three color-coded wires for connection to the ADAM-4500 terminal block. The
following figure shows how to connect the ADAM-4500 to the host computer.
RS-232
Red
White
Black
Female
DB-9
Host PC
(RS-232 PC)
RS-232
Male DB-9
HOST PC DOWNLOAD CABLE and ADAM-4500
Figure 2-2: Download Cable Connections

Step 3: Run utility software in host computer
Together with the ADAM-4500 you will find a utility disk containing an ADAM4500.EXE file. This file is a
menu-driven software utility provided for downloading user's programs. It uses a screen simulating
operation of the ADAM-4500 communication controller. When the file is executed, the main screen
appears, as shown in figure 2.3.
Figure 2-3: Main Screen
Setup COM port
First, highlight the "COMport" option on the top bar and press <enter>. The status field (shown below)
will appear. Second, highlight the COM port you used to connect the ADAM-4500 to the PC, then press
<enter>. The Baudrate is set to a default value of 57600 bps and cannot be changed. The screen is as
shown in figure 2.4.

Figure 2-4: Select Communication Port
Step 4: Power on ADAM-4500
Highlight the "Terminal" option, then press <enter>. Power on the ADAM-4500. After 5 seconds, the
screen shown in figure 2.5 will appear. The ADAM-4500 system is successfully started up.
Figure 2-5: Emulating Screen of ADAM-4500
2.3 Jumper Setting
We designed the ADAM-4500 with ease-of-use in mind. It has three jumper settings. The following
sections explain how to configure the module. You may want to refer to the figure below for help in
identifying card components.

The following diagram shows the locations of the jumpers:
Figure 2-6:Jumper Layout
COM1 Port Setting (JP1)
Jumper JP1 lets you configure the COM1(3F8) port as an RS-232 or as an RS-485 interface for different
applications. Jumper settings are shown below:
Watchdog Timer Setting (JP2)
Jumper JP2 lets you configure the watchdog timer in disable mode, reset mode or NMI (Non-maskable
interrupt) mode.
NMI RESET
JP2
JP2
Reset Mode Non-maskable
Interrupt (NMI)
NMI RESET
JP2
Disable Watchdog Timer
NMI RESET
(Default)
Reset Function Setting (JP3)
Jumper JP3 enables or disables the function of the reset pin, as shown below:
2.4 Communication Wiring
The ADAM-4500 offers two serial ports: COM1(3F8) in RS-232 or RS-485, and COM2 (2F8) in RS-485.
COM1 can be configured as an RS-232 or as an RS-485 interface via the jumper setting. This provides
flexibility for communications between the controller and other devices in your application.
RS-232 Connection
The ADAM-4500 has a DB-9 pin connector as its RS-232 port connector. Since the connection for an RS-
232 interface is not standardized, different devices implement the RS-232 connection in different ways. If
you are having problems with a serial device, be sure to check the pin assignments for the connector.
The following table shows the pin assignments for the ADAM-4500's RS-232 port.
Pin No. Description
1 DCD
2 RxD
3 TxD
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9 RI
Table 2-1: Pin Assignments of RS-232 Port

RS-485 Connection
The RS-485 standard supports half-duplex communication. This means that just two wires are needed to
both transmit and receive data. Handshaking signals (such as RTS, Request To Send) are normally used
to control the direction of the data flow. A special I/O circuit in the ADAM-4500 automatically senses the
direction of the data flow and switches the transmission direction. No handshaking signals are necessary.
This RS-485 control is completely transparent to the user.
We recommend that shielded twisted-pair cables complying with the EIA RS-485 standard be used in the
network to reduce interference. Only one set of twisted-pair cables is required to transmit both Data and
RTS signals. We advise use of the following standard colors for the communication cables.
DATA + Yellow
DATA - Green
Chapter 3 Programming and Downloading
This chapter explains how to program applications and download programs into the ADAM-4500
controller. Additionally, it points out limitations and concerns of which you should be aware.
3.1 Programming
The operating system of ADAM-4500 is ROM-DOS, an MS-DOS equivalent system. It allows users to run
application programs written in assembly language as well as high level languages such as C or C++.
However, there are limitations when running application programs in the ADAM-4500. In order to build
successful applications, you should keep the following limitations and concerns in mind.
Mini BIOS Functions
The ADAM-4500 provides only two serial communication ports for connecting peripherals, so the mini
BIOS of ADAM-4500 only provides 10 function calls. Since the user's program can not use other BIOS
function calls, the ADAM-4500 may not work as intended. Additionally, certain language compilers such
as QBASIC directly call BIOS functions that are not executable in ADAM-4500. The ADAM-4500 mini
BIOS function calls are listed in the following table.
Function Subfunction Task
07h 186 or greater co-processor esc instruct
10h 0eh TTY Clear output
11h Get equipment
12h Get memory size
15h 87h Extended memory read
88h Extended memory size
c0h PS/2 or AT style A20 Gate table
16h 0 Read TTY char
1 Get TTY status
2 Get TTY flags
18h Print "Failed to BOOT ROM-DOS" message
19h Reboot system
1ah 0 Get tick count
1 Set tick count
2 Get real time clock
3 Set real time clock
4 Get date
5 Set date
1ch Timertick

Converting Program Codes
The ADAM-4500 has an 80188 CPU. Therefore, programs downloaded into its flash ROM must first be
converted into 80186 or 80188 compatible code, and the floating point operation must be set to emulation
mode. For example, if you were to develop your application program in Borland C, you would compile the
program as indicated in the screen below.
Figure 3-1: Converting Program Codes
Other Limitations
1. The ADAM-4500 does not support the standard PC function "8253". Therefore, the C language
function call "delay ( )" cannot be used in ADAM-4500 applications.
2. Certain critical files are always kept in flash ROM, such as the operating system files, BIOS, and
monitoring files. Aside from the storage space needed for these critical files, the ADAM-4500 has an
additional 170 KB of free ROM space for downloading user applications. An additional free 234 KB of
SRAM is provided for operation of applications.
Programming the Watchdog Timer
The ADAM-4500 is equipped with a watchdog timer function that resets the CPU or generates an
interrupt if processing comes to a standstill for any reason. This feature increases system reliability in
industrial standalone and unmanned environments.
If you decide to use the watchdog timer, you must write a function call to enable it. When the watchdog
timer is enabled, it must be cleared by the application program at intervals of less than 1.6 seconds. If it
is not cleared at the required time intervals, it will activate and reset the CPU, or generate an NMI (Non-
maskable interrupt). You can use a function call in your application program to clear the watchdog timer.
At the end of your program, you need an additional function call to disable the watchdog timer.
The following program shows how you might program the watchdog timer in C programs:

Example:
main ()
{
wdt_enable(); /* enable ADAM-4500 WDT function */
{ /* user's function block */
.
.
wdt_clear(); /* clear WDT timer */
.
.
}
wdt_disable(); /* disable ADAM-4500 WDT function */
}
Interrupt Types
Three types of interrupts may occur in the ADAM-4500. The following table shows the types of interrupts.
Interrupt Name Interrupt Type
Non-Maskable Interrupt (NMI) 02h
COM1 Interrupt 0Ch
COM2 Interrupt 0Eh
Memory Mapping
The following table shows the memory mapping of the ADAM-4500 controller.
0xF8000 -- 0xFFFFF Monitor program
0xF6C00 -- 0xF7FFF Mini BIOS
0xCC000 Start of Application ROM Disk (about 171 K)
0xC0000 Start of ROM-DOS (about 48 K)
0x40000 -- 0xBFFFF No Use
0x00400 -- 0x3FFFF SRAM area
0x00000 -- 0x003FF System area
0x003F8 -- 0x003FF COM1
0x002F8 -- 0x002FF COM2
0x00070 -- 0x00071 Real time clock
3.2 Downloading and Transferring
This section explains how to download application programs from a PC into the ADAM-4500 flash ROM
and how to transfer files from a PC into ADAM-4500's SRAM.
Install Utility Software on Host PC
A utility disk containing the following files and directories is included with each ADAM-4500.
. ALLFILE <DIR>
. LIBRARY <DIR>
. EXAMPLE <DIR>
. ADAMMINI.HEX
. ADAM_DEM.HEX
. ROM-DOS.HEX
. DEMO-DIS.HEX
. ADAMMINI.BAT
. ADAM4500.EXE
. HEXCAT.EXE
. ROMDISK.EXE
Copy all the files and directories on the utility disk to the host computer hard drive.

Preparing the ALLFILE directory
Applications programs are downloaded from a host-PC to the flash ROM of the ADAM-4500 using the
ADAM-4500 utility software. The ADAM-4500 utility software is first installed on a host-PC. The directory
ALLFILE will be included among the contents copied from the utility software disk to the host-PC hard
drive. The user must then load into ALLFILE the following required files: The application program
intended for installation in ADAM-4500; COMMAND.COM; AUTOEXEC.BAT; and CONFIG.SYS. The
user should make certain that AUTOEXEC.BAT contains the name of the user's application program so
that the application will automatically begin executing whenever the ADAM-4500 is powered on. When
downloading to the ADAM-4500's flash ROM, the utility software first clears all non-permanent files from
the flash ROM, then installs all the files contained in directory ALLFILE into the flash ROM. It is therefore
critical that all the required files be available in directory ALLFILE when the utility software tries to install
ALLFILE's contents on the ADAM-4500's flash ROM.
Downloading into flash ROM (ADAM-4500's C-drive)
With the ADAM-4500 utility software and the directory ALLFILE, loaded with its proper contents, installed
on the host-PC, you can execute the utility software. After the utility software has begun executing, select
the COMport of the host PC that has been connected to ADAM-4500. Then select "Program" from the
bar menu and press <enter> to begin downloading. The screen shown in figure 3-2 will appear.
Figure 3-2: Program downloading
Follow the instructions shown on the screen. Power off the ADAM-4500 and then re-power on. Then
press any key within 7 seconds to burn the files contained in ALLFILE into the ADAM-4500's flash ROM.
After the files are successfully burned into the flash ROM, the screen in Figure 3-3 will appear. Power off
and power on the ADAM-4500 once again. The ADAM-4500 controller will automatically execute the
application program.

Figure 3-3: Download Complete
Transferring files to SRAM (ADAM-4500's D-drive)
The ADAM-4500 provides 234 KB of free SRAM for use in program operation, and as working memory
space in the event you want to test your system control logic or simulate system performance before
downloading the execution code to the flash ROM. You can transfer files from a host-PC to the ADAM-
4500's SRAM (D drive). Execute the utility software, select terminal mode, and press Alt-T. File transfer
will begin and the screen shown in figure 3-4 will appear.
Figure 3-4: File Transferring
Key in the specific directory and file names you want to transfer. Press <enter> to complete the file
transfer. You can check the files in D drive.
We recommend that users test new applications on their host PC before installing them in the ADAM-
4500. However, the performance of the host PC may differ greatly from that of the ADAM-4500.
Therefore, users may find it desirable to install an application that has been tested on the host PC into

ADAM-4500's D drive for testing prior to burning it into the flash ROM. It takes less time to alter and
reinstall a program into the SRAM than into the flash ROM, so using the SRAM during debugging on the
ADAM-4500 may be more efficient.
3.3 Steps to Building a Successful Application
Step 1: Write and simulate control logic on a PC
Connect a host-PC to the I/O device network you want to control. Write the control logic for your
application on the host-PC and execute the application on the PC to verify that it works properly.
Step 2: Connect the cables
Replace the host-PC in the control network with the ADAM-4500 and reconnect the proper power and
communications cable in the network to the ADAM-4500. Connect the download cable between the host-
PC and the ADAM-4500.
Step 3: Convert and download codes to flash ROM
Within the host computer, convert the application program into 80186 or 80188 compatible code. Create
an AUTOEXEC.BAT file for the application program and write the application program's name in the
AUTOEXEC.BAT file. Also create COMMAND.COM and CONFIG.SYS files for the application program.
Load the ADAM-4500 utility software into the host-PC. Load the converted application program and the
files AUTOEXEC.BAT, COMMAND.COM, and CONFIG.SYS into directory ALLFILE. Execute the utility
software to download the contents of ALLFILE into the ADAM-4500 flash ROM.
Step 4: Power on ADAM-4500 to complete the application
After all the files in directory ALLFILE have been completely transferred to the flash ROM, re-power on
the ADAM-4500.
Chapter 4 Function Library
The ADAM-4500 is packaged with a utility disk that contains a directory called LIBRARY. This directory
contains a number of function calls that enable a user to efficiently write applications for ADAM-4500. The
library supports both Turbo C 2.0 and Microsoft C 6.0 version programming languages.
The "LIBRARY" directory contains the following two sub-directories:
. TC20 Library for Turbo C 2.0 version
. MSC60 Library for Microsoft C 6.0 version
Function Library for Turbo C
The TC20 directory contains the following files:
ADAM4500.H Declaration file
4500L.LIB Library file for compiling large mode
4500S.LIB Library file for compiling small mode
Function Library for Microsoft C
The MSC60 directory contains the following files:
ADAM4500.H Declaration file
4500L.LIB Library file for compiler large mode
4500C.LIB Library file for compiler compact mode
4500M.LIB Library file for compiler medium mode
4500S.LIB Library file for compiler small mode

The function calls included in the directory LIBRARY are described in the following pages.
comm_init
Syntax:
int comm_init(int buf_size)
Function description:
Initializes the communication port and interrupt routine before other function calls use the communication
port.
Parameter Description
int buf_size Sets the buffer size of every communication port for storage of received
data. The unit of size is bytes.
Return:
Returns a 1 if command succeeds. Returns a 0 if it fails.
comm_exit
Syntax:
int comm_exit()
Function Description:
If a user calls the comm_init function, the user must call this function to release the communication port
before the user's program terminates.
Return:
Returns a 1 if command succeeds. Return a 0 if it fails.
comm_open
Syntax:
int comm_open(unsigned char port, unsigned long baud, int parity, int data, int stop, int cmd_type)
Function Description:
To open a communication port for user to send and receive data.
Parameter Description
unsigned char port Specifies communication port.
1:COM1port
2: COM2 port
unsigned long baud Baud rate setting. The eight allowable baud rates are: 1200, 2400, 4800,
9600, 19200, 38400, 57600, and 115200. Sized in bps (bits per second).
int parity Parity setting.
0: no parity, 1: odd, 2: even
int data Data bits setting. There are four allowable data lengths: 8, 7, 6, and 5.
Sized in bit units.

int stop Stop bits setting
1,2
(stop bit = 1 is for data bits = 5,6,7, or 8)
(stop bit = 2 is for data bits = 6,7, or 8)
For details, refer to RS-232 chip set data book
int cmd_type Received data format setting.
0: single byte mode. The data format is a single byte character.
User can use comm_get_rec_datas to receive single byte data.
1: command mode. The data format is a string. User can use
comm_get_rec_str to receive string data.
Return:
Returns a 1 if command succeeds. Returns a 0 if it fails.
comm_send
Syntax:
int comm_send(unsigned char c, unsigned char port)
Function Description:
To send a character to a specified communication port.
Parameter Description
unsigned char c Represents character to be sent.
unsigned char port Specifies communication port to which character is sent (COM1 or
COM2)
1: COM1 port
2:COM2port
Return:
Returns a 1 if command succeeds. Returns a 0 if it fails.
comm_get_rec_datas
Syntax:
int comm_get_rec_datas(unsigned *length, unsigned char **data, unsigned char port)
Function Description :
The function is called to receive a single byte of data. The function call returns a success flag if the
communication port receives any data. The function call returns a failed flag if the buffer of the
communication port is empty. The length of the data packet received (in bytes) is stored in parameter
"length". The contents of the data packet received are stored in parameter "data".
Parameter Description
unsigned *length Returns the length of the received data
unsigned char **data Returns the received data contents. User must first allocate a
data buffer ( Use comm_int function call ). Before exiting program, user
must free this buffer ( Use comm_exit function call ).
unsigned char port Specifies communication port (COM1 or COM2)
1:COM1port
2:COM2port

Return:
Returns a 1 if command succeeds. Returns a 0 if it fails.
comm_get_rec_str
Syntax:
int comm_get_rec_str(unsigned char **data, unsigned char port)
Function Description:
This function call is employed to received string data. The function call returns a success flag if the
communication port receives string data ( terminal character is 0x0d) . The function call returns a fail flag
if the buffer of the communication port is empty.
Parameter Description
unsigned char **data Returns the received string contents. User must first allocate a
data buffer (Use comm_int function call). Before exiting program, user
must free this buffer (Use comm_exit function call).
unsigned char port Specifies communication port (COM1 or COM2)
1:COM1port
2:COM2port
Return:
Returns a 1 if command succeeds. Returns a 0 if it fails.
led_init
Syntax:
void led_init()
Function Description:
This function must be called to initialize the ADAM-4500's LED before a user's program can control the
LED.
led
Syntax:
void led(int type)
Function Description:
LED ON/OFF control
Parameter Description
int type 0: LED OFF
1:LEDON
wdt_enable
Syntax:
wdt_enable()

Function Description:
This function enables the watchdog timer function. After a user calls this function, the user must call the
wdt_clear() function to refresh the watchdog timer; otherwise the CPU resets, or a non-maskable interrupt
is generated.
wdt_clear
Syntax:
wdt_clear()
Function Description:
This function refreshes the watchdog timer, thereby avoiding the resetting of the CPU or the generation of
a non-maskable interrupt.
wdt_disable
Syntax:
wdt_disable()
Function Description:
This function disables the watchdog timer function.
Appendix A Register Structure
This appendix gives a short description of each of the ADAM-4500's registers. For more information
please refer to the data book for the STARTECH 16C550 UART chip.
All registers are one byte in length. Bit 0 is the least significant bit, and bit 7 is the most significant bit. The
address of each register is specified as an offset from the port base address (BASE), COM1 is 3F8h and
COM2 is 2F8h.
DLAB is the "Divisor Latch Access Bit", bit 7 of BASE+3.
BASE+0 Receiver buffer register when DLAB=0 and the operation is a read.
BASE+0 Transmitter holding register when DLAB=0 and the operation is a write.
BASE+0 Divisor latch bits 0 - 7 when DLAB=1
BASE+1 Divisor latch bits 8-15 when DLAB=1.
The two bytes BASE+0 and BASE+1 together form a 16-bit number, the divisor, which determines the
baud rate. Set the divisor as follows:
Baud rate Divisor Baud rate Divisor
50 2304 2400 48
75 1536 3600 32
110 1047 4800 24
133.5 857 7200 16
150 768 9600 12
300 384 19200 6
600 192 38400 3
1200 96 56000 2
1800 64 115200 1
2000 58