Panasonic FP2 ET-LAN Technical Manual page 131

Procedure when receiving data
When the size of the data received is less than or equal to the reception request data size, the following
procedure is used to carry out communication processing.
When data is received from the communication circuit, the receive notified signal goes on.
The size of the data to be read is written to the reception request data size parameter in the
connection information setting area.
The receive request signal is turned on.
The received data is sent to the receive buffer in the shared memory.
The receive complete signal goes on.
The received data is read from the receive buffer in the shared memory.
The receive request signal goes off.
When the receive request signal has been turned off, the receive complete signal goes off.
If the reception processing is not successfully completed for some reason, the receive error signal
goes on.
If a reception error occurs, the receive request signal goes off.
When the receive request signal goes off, the receive error signal goes off. Always make sure this
has been done before carrying out the reception processing again.
When the size of the data received is greater than the receive request data size, the following procedure
is used to carry out communication processing.
Even if the receive request signal goes off, the receive notified signal remains on, so repeat the
procedure from step
Operation when an error occurs is the same as that which occurs when the size of the data received is
less than or equal to the receive request data size.
Key Point:
The size of the transparent reception data remaining in the ET-LAN unit is stored in the receive
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unnotified data size area of the shared memory.
If the receive unnotified data size matches the receive unnotifed data size copy, the size of the
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remaining data is entered. After the two have been matched, a request for reception of the remaining
data should be issued based on this value.
, when the receive request signal goes on, to receive the remaining data.
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