Direct Writing To The Hp-Ib Lines - HP 8340A Operating Manual

Model 8340A
Here is a BASIC example of reading the status registers:
100 FOR N = 0 TO 6
110 STATUS 7,N; S
120 PRINT "STATUS REGISTER"; N
130 PRINT
140
FOR J = 0 TO 7
PRINT "BIT'';J;" = "; BIT( S, J )
150
160 NEXT J
170 PRINT
180 NEXT N

Direct Writing to the HP-IB lines

The final programming technique covered in this manual involves direct writing to the HP­
IB data, handshake, and control lines. This is very advanced programming, and should be
attempted only by experienced programmers who are thoroughly familiar with the HP
8340A and HP-IB protocols.
Bus malfunctions or damage can result from errant applications of
direct writing to HP-IB lines.
Direct writing to the HP-IB lines is accomplished by the CONTROL statement, which has
this syntax:
HP 85A:
HP 9826/9836:
READIO
WRITEIO
The CONTROL statement ( ASSERT, READIO/WRITEIO are related statements used by
some computers ) is used to send information to the computer's control registers, which have
bit patterns that correspond to the HP-IB lines. The bit pattern of the control registers is
computer specific; Figure 3-28 shows representative control registers from the HP 9826 and
HP-85A computers.
interface
select code
interface
select code
interface register
select code number
Scans by HB9HCA and HB9FSX
register control
number byte
register
number
register
data
Operating Information
3-91