Jetter JC-120MC, User Manual

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540 Jetter AG
10 Programming
Internal processes of the CAN-Prim interface
The CAN-Prim interface processes the following tasks independently:
 Sending of CAN messages
 Reception of CAN messages

Filtering of CAN messages on reception
The CAN-Prim interface receives new CAN messages in the following way:
Step Description
1
The CAN bus receives a valid CAN message.
2 The CAN-ID matches the receiving mask.
3
The CAN-ID matches the CAN-ID of a message box which has been
configured as inbox.
4 If in R 200 message box
number *20 of the message box
...
... then ...
... bit 1 NEW-DAT = 0, ... bit 1 NEW-DAT becomes = 1;
proceed with step 5
... bit 1 NEW-DAT = 1, ... bit 2 OVERRUN becomes = 1;
CAN message data are discarded.
5 R 200010503 FIFO filling level is incremented.
This register shows whether new CAN messages have been received, as
well as the number of messages.
6 The message box number is entered into R 200010504 FIFO data .
This register shows which of the messages boxes has received a new
CAN message.
7 In R 200010500 CAN-Prim Status , bit 1 NEW DAT = 1.
Introduction
Internal reception of
CAN messages