HP 7470A Interfacing And Programming Manual page 25

E-Mask Error
Bit Value Bit Number Meaning
1 O 1 Instruction not recognized
2 1 2 Wrong number of parameters
4 2 3 Bad parameter
8 3 4 Not used
16 4 5 Unknown character set
32 5 6 Position overflow
64 6 7 Not used ,
128 7 8 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—maskin 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 Status Bit
Bit Value Number Meaning
1 0 Pen down
2 1 P1 or P2 changed
4 2 Digitized point available
8 3 lnitialized
16 4 Ready for data; pinch wheels down
32 5 Error
64 6 Not used
128 7 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.
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