Measurement-computing Personal488 rev.3.0 For DOS & Windows 3.Xi Manual de usuario descargar pdf (Pagina 124)

II. SOFTWARE GUIDES - 8. Driver488/DRV 8M. Data Transfers

Personal488 User’s Manual, Rev. 3.0 II-109

•

IEEEIO.BAS

: Communications routines for Driver488/DRV.

•

IEEEIO.ASM

: Assembly language file for direct DOS access without Turbo Basic interference.

•

IEEEIO.COM

: Executable version of

IEEEIO.ASM

•

KYBDCTRL.BAS

: Turbo Basic version of the Keyboard Controller Program.

The actual demonstration program is contained in

195DEMO.BAS

. These examples also require the file

REGNAMES.INC

which is included with Turbo Basic.

Terminators

Every transfer of data, between a program and Driver488/DRV, or between Driver488/DRV and a bus

device, must have a definite end. This is a common requirement in most systems. For example, most

printers do not print a line until they receive the carriage return that ends that line. Similarly, a BASIC

INPUT

statement waits for the

<Enter>

key to be pressed before returning the entered data to the

program. The only time that some terminator is not required is when the number of characters that

compose the data is known in advance or is transferred along with the data. This is the case, for

example, when fixed-length records are read from a random access disk file.

Driver488/DRV actually uses four terminators:

•

The end-of-line (

EOL

) terminator for output from the program to Driver488/DRV.

•

The end-of-line (

EOL

) terminator for input to the program from Driver488/DRV.

•

The data terminator (

TERM

) for output to bus devices from Driver488/DRV.

•

The data terminator (

TERM

) to input from bus device into Driver488/DRV.

End-Of-Line (EOL) Terminators

The

EOL

terminators mark the end of character strings transferred between the user’s program and

Driver488/DRV. The

EOL

output terminator marks the end of strings transferred from the user’s

program to Driver488/DRV, and the

EOL

input terminator marks the end of strings transferred into the

user’s program from Driver488/DRV.

The

EOL

terminators normally consist of one or two ASCII characters. The characters do not need to

be printable. In fact they are usually special characters such as carriage return and line feed. Also,

input and output terminators need not be the same.

It is possible to specify that no characters are to be used as

EOL

terminators. If the

EOL

output

terminator is set to

NONE

, then Driver488/DRV assumes that it receives an entire command in each

8M. Data Transfers

Topics

•

Terminators................................................................................... II-108

End-Of-Line (EOL) Terminators................................................................II-108

TERM Terminators......................................................................................II-112

•

Direct I/O & Buffered I/O............................................................ II-113

Direct Bus OUTPUT.....................................................................................II-113

Direct Bus ENTER .......................................................................................II-113

Buffered I/O...................................................................................................II-114

•

Asynchronous Transfers............................................................. II-115

1 2 ... 119 120 121 122 123 124 125 126 127 128 129 ... 399 400

Comentarios a estos manuales

Sin comentarios

Measurement-computing Personal488 rev.3.0 For DOS & Windows 3.Xi Manual de usuario Pagina 124

Comentarios a estos manuales

Relacionado con productos y manuales para Hardware Measurement-computing Personal488 rev.3.0 For DOS & Windows 3.Xi