Glossary
162
stack pointer
A microprocessor index register used for assembly language programming.
start address
The starting address of a block of data. This term is used as a parameter in
many of the assembly language monitor mode commands.
start mode
Indicates how the ASCII Unit starts up when power is first applied or the Unit
is reset. The two choices are manual mode and automatic mode. The mode
can be selected by setting pins one and two of the left-side DIP switch.
START/STOP switch
A toggle switch on the front panel of the ASCII Unit used for starting and
stopping execution of the ASCII Unit program.
upload/download
Upload usually refers to the transfer of a program or information from a re-
mote device to a computer or other controlling device. Download usually re-
fers to data transfer from a computer or other controlling device to a remote
device. From the users point of view, if data is being sent to another device, it
is being downloaded. If data is being received from another device, it is being
uploaded.
valid signal line
A parameter of the OPEN command which specifies which communication
signals (CTS, DSR, RTS) are to be used for handshaking.
watchdog timer
A clock on the PC that measures the time it takes the PC program to com-
plete one scan. If the scan time is longer than 100 ms, a warning is issued. If
the scan time is longer than 130 ms, the PC will suspend operation. The
watchdog timer is reset at the beginning of each scan.
word
A word is made up of two bytes or 16 bits. The term “word” is used inter-
changeably with the term “data word” to indicate a single unit of data. Blocks
of data are transferred in “word” units. For data transfer, the address of a
data block’s first “word” and the number of “words” to be transferred must be
specified.
Write Flag
A PC hardware flag that indicates when data can be written to the PC. When
this flag is set, data can be written to the PC.
XON/XOFF
OPEN statement parameters that control the rate at which the port buffers
receive and transmit data. If the XON command is specified to be ON by the
OPEN statement, then when the port buffer becomes 3/4 full, the ASCII Unit
will suspend data transfer until the port buffer is less than 1/4 full. In a case
where a transmitting device is sending data at a faster baud rate than the
ASCII Unit is set for, the XON command will keep the transmitted data from
being written over.
Summary of Contents for SYSMAC C200H-ASC02
Page 1: ...Cat No W165 E1 04 ASCII Unit SYSMAC C200H ASC02 ...
Page 2: ...C200H ASC02 ASCII Unit Operation Manual Revised September 2002 ...
Page 3: ...iv ...
Page 5: ...vi ...
Page 7: ...TABLE OF CONTENTS viii Glossary 159 Index 163 Revision History 165 ...
Page 122: ...Appendix B Specifications 115 130 35 100 5 ...
Page 168: ...Cat No W165 E1 04 C200H ASC02 ASCII Unit OPERATION MANUAL ...