Measurement Computing Digital488 User Manual
Page 42
Section 3 Command Descriptions
3.12
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:
DIM A$[50]
dimension the length of A$
CLEAR 718
reset the Digital488
OUTPUT 718;"C2G2X"
configure ports 1 & 2 as output
OUTPUT 718;"D4E6BZX"
output hexadecimal 4E6B to ports 1 & 2
ENTER 718; A$
read data from the Digital488
DISP A$
display shows 4E6B
F1 Format - ASCII Character
In the F1 format, the data is coded and transmitted in ASCII Characters with the
four least significant bits of each ASCII character representing four bits of data.
F1 Character Decimal Equiv F1 Character Decimal Equiv
0
0
8
8
1
1
9
9
2
2
:
10
3
3
;
11
4
4
<
12
5
5
=
13
6
6
>
14
7
7
?
15
Data received for output to the digital ports must be contained within a prefix (D)
and a suffix (Z). 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.