4
4-2
SCPI commands and IEEE-488.2 commands are parsed and used to set control
parameters, perform an operation or query a parameter. Responses are placed
in the output buffer so they can be returned to the client when the unit is next
addressed to talk. The other VXI-11.3 commands like Device Clear clears the
serial buffers. Device Trigger has no affect on the 8099. The ReadSTB com-
mand causes the 8099 to respond as a GPIB device would to a Serial Poll.
4.3
BLOCK DIAGRAM DESCRIPTION
Figure 4-2 shows a block diagram of the 8099’s internal logic. The 8099 is a
microprocessor based device that accepts commands from the TCP/IP network
to control its digital outputs and to read digital inputs. The 8099 is made up of
eight major elements, most of which are interconnected to the microprocessor
by a common data, address and control signal bus.
Incoming network messages are received by the LAN Interface chip. The LAN
Interface chip transfers the message to the TCP Stack which then notifies the
microprocessor when it has a message. The command characters are parsed
and used to change the 8099’s operational settings or invoke some action or a
Figure 4-2 8099 Block Diagram
5 VDC
Input
+5V
3.3V
Reg
+3.3V
ARM7 Processor
Reset Button
RAM
+5
+5
Latch
Diagnostic LEDs
Address
DCDR
µP BUS
FLASH
LAN
INTFC
Fltr
TCP/IP
LAN
RS-422/RS-485
RS-232
Serial Interfaces
Содержание 8099
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