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5-3-5. Random Pair and Group Conference Control
a) Outline
The random pair formation and the group conference formation are established by transferring data from
the GUI (personal computer) to the CPU-240 board, then by transferring data from the CPU-240 board to
the ASW-58 board.
Therefore, they cannot be controlled from the OPU panel.
1) When the CPU-240 board receives the formation data to constitute a random student pair or a confer-
ence group, the CPU-240 board sends the formation data to the ASW-58 board.
Using this data transfer route, any key operations on the OPU or GUI, such as monitoring, model
presentation or intercommunication (intercom) in the random student pair or a conference group
mode, are processed (opening/closing the analog switches on the IF-645A board, transferring the
commands to ER, or turning on/off the LEDs on OPU, etc.).
2) When the ASW-58 board receives the formation data to constitute a random student pair or a confer-
ence group, the ASW-58 board opens and closes the analog switches on the ASW-58 board.
b) SIO communication clock from the CPU-240 board.
Because the SIO communication clock of the ASW-58 board and the SIO transfer clock for communica-
tion with ER, are generated by the same timer generator inside the CPU, the CPU timer oscillates at 153.6
kHz while the SIO communication speed of the ASW-58 board is set to 9600 baud and the SIO communi-
cation speed of ER is set to 2400 baud.
1) ASW-58 board communication specifications
Speed :
9600 baud
Data :
8 bits
Start bit :
1 bit
Stop bit :
1 bit (no parity)
2) ER communication specifications (Same as the conventional LLC-8000 specifications)
Speed :
2400 baud
Data :
7 bits
Start bit :
1 bit
Stop bit :
1 bit (no parity)
C) Controlling data transmission to the ASW-58 board
The port that is assigned for communication with the ASW-58 board, shares the hardware that is designed
for communication with ER. Therefore, the port is controlled by gate T5 in the same manner as the other
transmission ports to ER.
As a result, the communication sequence with ER (this communication is performed all the time) is
temporarily interrupted, and the required data is sent to the ASW-58 board. After sending data to the
ASW-58 board, communication with ER is resumed.
The transmission data is sent to the ASW-58 board byte by byte every 2 ms using a timer interrupt. The
number of bytes of the longest command is 97 bytes, resulting in the maximum interrupt time of 194 ms.
Transmission/reception timing chart
TXB1 to 4
(ER transmission port)
RXB1 to 4
(ER reception port)
T5
(Transmission/reception control)
TXB5
(ASW-58 transmission port)
RXB5
(ASW-58 reception port)
n
If the status is not returned within 0.5 seconds normally after the status request command is issued, a
maximum of 0.5 seconds is the waiting time for reception of the status return. (Retry operation)
When the retry operation is repeated twice but the status is not returned normally, it is judged that the
ASW-58 board is not connected and the necessary processing is performed.
The status request command is transmitted whenever the main power is turned on.
5-10
5-10
Maximum 194 ms (= 97 bytes x 2 ms)
Maximum response-wait time after the status request command is issued (= 0.5 s)
LLC-8000A
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