AcroPack Series AP560
CAN Bus Interface Module
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b) The message is not successful due to lost arbitration or message error.
i.
Lost Arbitration:
If arbitration is lost, the current
message stays in the Transmit Buffer for re-
transmission.
ii.
Message error:
Flag BUSERR is set in the Interrupt
Flag Register. An error frame is sent and an optional
hardware interrupt may also be generated at the INT
pin if enabled in the Interrupt Enable Register (bit
BUSERRIE = 1). If there is an error, the current message
stays in the Transmit Buffer for automatic re-
transmission in accordance with the CAN protocol.
NOTE: If OSM is set, re-transmission will NOT be
attempted upon loss of arbitration or message error.
The existing message will remain in the FIFO. If the
user requires a new message on the next transmission
cycle, the FIFO must be cleared using command 0x54
and re-loaded with the new message.
LOADING THE TRANSMIT FIFO
The transmit FIFO in the HI-3111 holds up to eight messages (see Table 29).
The host simply needs to first write the data bytes to the Channel X output
message registers for the selected channel. Next the host must write
command code 0x12 to the Channel X command register. For standard
frames, the data field has the format shown in Table 30. For extended frames,
the data field has the format shown in Table 31. The HI-3111 will
automatically interpret Standard or Extended frames by decoding the IDE bit.
The HI-3111 also decodes the data length code (DLC) and ignores data bytes
greater than the DLC value (
Note:
a DLC of greater than eight is automatically
assumed to be equal to eight). The user has the option of assigning a unique
message tag to each message which can be used later to identify successfully
transmitted messages from the transmit history FIFO. One frame at a time can
be loaded to the transmit FIFO using command 0x12.
Transmit History FIFO
The Transmit History FIFO can optionally be used by the host to keep a record
of up to eight successfully transmitted messages. A user-assigned message tag
and a time tag are stored for each message. The data format is shown in Table
32. The time tag is assigned from the value of the free running counter upon
receipt of an ACK bit. The transmit history FIFO is cleared when read by
command 0xEE (see Table 29).
Содержание AcroPack AP560
Страница 28: ...AcroPack Series AP560 CAN Bus Interface Module 28 Figure 2 Standard Data Frame...
Страница 30: ...AcroPack Series AP560 CAN Bus Interface Module 30 Figure 3 Extended Data Frame...
Страница 32: ...AcroPack Series AP560 CAN Bus Interface Module 32 Figure 4 Remote Frame...
Страница 34: ...AcroPack Series AP560 CAN Bus Interface Module 34 Figure 5 Error Frame...
