The Input Mask Instruction, Im - HP 7470A Interfacing And Programming Manual

)
>. I^HUMi'MIHli'l NO parameters are used; a numeric parameter will K.-—«-3
J cause error 2 and the instruction will not execute. I
) An IN command is the equivalent of switching the plotter off and then
"\ on again (except that conditions set by escape code sequences are not
changed in an RS-232-C environment). The initialize command sets the
) plotter to the same conditions as the default command and sets these
additional conditions.
v • The pen is raised. 1ft! ™^3
• The scaling points P i and P2 are set to the points PI = 250,279 and ^ ~ " ^
) P2 = 10 250,7479.
) • All HP-GL errors are cleared. Bit position 3 of the output status byte ifW' J| j
-v is set to true(l) indicating the plotter has been initialized. (This bit is 1
) cleared by OS.) '
) • The setting of the US/A4 switch (for paper size) is read, t h u s
\ establishing the limits within which the pen can move (mechanical
hard clip limits).
T
E l SJ
The Input Mask Instruction, IM
J HlwHHIillFlltl The input mask instruction, IM, controls the conditions
~ N under which HP-GL error status is reported, the conditions that can
' cause an HP-IB service request message, and the conditions that can
cause a positive response to an HP-IB parallel poll.
UWM With all three interface configurations (HP-IB, HP-IL, and RS- —*
3
232-C), this instruction can be used to change the conditions under fT^~^~3
which HP-GL error status is reported. In an HP-IB system only, the
instruction is used to enable the plotter to send a service request « ! r-—.
message when specified bits of the status byte are set, and/or enable a i ^ ' J_3
- - " " " " \
positive response to a parallel poll under the conditions specified.
"\ BJiJIiftl IM E-mask value (,S-mask value (,P-mask value))
(terminator)
or
IM (terminator)
■9<JI:Ui1llllfl
I n b o t h
the RS-232-C and HP-IL configurations, the S-
and P-masks are of no use and are ignored if present. The E-mask is H J , _
used by all three configurations. J 5 « ^ J j
The E-mask value specified is the sum of any combination.of the bit
values shown in the following table. When an HP-GL error occurs, the
bit in the E-mask corresponding to the error number as shown below is
tested to determine if the error bit (bit 5) of the status byte is to be set
and the front panel ERROR LED is to be turned on. If a bit is not set,
there is no way to ever determine if that error occurred.
12 GETTING STARTED
EH3
E-Mask
Bit Value
1
2
4
8
16
32
64
128
Bit
0
1
2
3
4
5
6
7
E r r o r
N u m b e r
1
2
3
4
5
6
7
8
M e a n i n g
Instruction not recognized
Wrong number of parameters
Bad parameter
Not used
Unknown character set
Position overflow
Not used
Vector or PD received with pinch
wheels up
The default E-mask value of 223 (128 + 64 + 16 + 8 + 4 + 2 + 1) will
specify that all errors except error 6 will set the error bit in the status
byte and turn on the ERROR LED whenever they occur. Error 6 will not
set the error bit or turn on the ERROR LED if it occurs, since it is not
included in the E-mask value. Errors 4 and 7 never occur so setting the
E-mask to 151 will set the same conditions as the default value 223.
The S-mask value specified is the sum of any of the bit values shown
below. It determines when a service request message will be sent. When
a bit of the status byte changes value, the status byte is ANDed with
the S-mask in a bit-by-bit fashion to determine if bit 6 of the status byte
is to be set and the service request message sent. The status of bit 6
changes as plotter conditions change, and is cleared or set as required.
S-Mask
Bit Value
1
2
4
8
16
32
64
128
S t a t u s Bit
N u m b e r
0
1
2
3
4
5
6
7
M e a n i n g
Pen down
PI or P2 changed
Digitized point available
Initialized
Ready for data; pinch wheels down
Error
Not used
Not used
For example, an S-mask value of 4 specifies that when a digitized point
is available, setting bit 2, the service request message will be sent.
Setting other bits will not send the service request message.
GETTING STARTED 1-13