IOtech Digital488, Manual

Page: 28 / 64

Digital488 User’s Manual
7-17-01
Command Descriptions, 3-7
F2 Format - ASCII Binary
In the F2 format, the each data bit is described with an ASCII 0 or 1. Each byte is formatted in two 4-bit
multiples separated by semicolons.
F2 String Decimal Equiv F2 String Decimal Equiv
0000;0000 0 0000;1001 9
0000;0001 1 0000;1010 10
0000;0010 2 0000;1011 11
0000;0011 3 0000;1100 12
0000;0100 4 0000;1101 13
0000;0101 5 0000;1110 14
0000;0110 6 0000;1111 15
0000;0111 7 1000;0001 129
0000;1000 8 1111;1111 255
Data received for output to the digital ports must be contained within a prefix ( D ) and a suffix ( Z ) and each
4-bit quantity must be separated by semicolons. Leading zeros are not required. If the amount of data sent
is less than the number of bits programmed as outputs, the least-significant bits will contain the data sent
and the most-significant bits will be cleared to logic zero. If the data sent is greater than the number of bits
programmed for output or selected by the
Pn command, the Digital488 will generate a conflict error and
ignore the entire command string. The Data Strobe output is pulse for approximately 50 microseconds
after new data is output on the selected port(s).
When the Digital488 is addressed to talk ( R0 ) it asserts Inhibit , reads the data from all ports, unasserts
Inhibit and outputs the number of characters determined by the Gn and Pn commands. Leading zeros are
not suppressed and the bus terminators are appended to the output. After output the Digital488 must be re-
addressed to talk to perform subsequent reads. EDR ( R1 ) may also be used to capture data in this format.
Example:
OUTPUT 718;"F2X" select ASCII/binary mode
ENTER 718;A$ read data from the Digital488
DISP A$
display shows
0001;1111;1111;0001
OUTPUT 718;"D1111;0;1010;0101ZX"
ENTER 718; A$ read data from the Digital488
DISP A$
display shows 1111;0000;1010;0101
F3 Format - ASCII Decimal
In the F3 format, the data is described in decimal 8 bit multiples and transmitted in ASCII. Each decimal
number (0 to 255) to be output must be separated by semicolons.
F3 Number Decimal Equiv F3 Number Decimal Equiv
000 0 008 8
001 1 009 9
002 2 010 10
003 3 020 20
004 4 100 100
005 5 200 200
006 6 210 210
007 7 255 255