upd70f3422gj-gae-qs-ax Renesas Electronics Corporation., upd70f3422gj-gae-qs-ax Datasheet - Page 722

• Manufacturer Part Number: upd70f3422gj-gae-qs-ax
• Description: 32-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

Chapter 19
722
Priority
1 (high)
2
3
4
5 (low)
Conditions
Value of first 11 bits of ID
[ID28 to ID18]:
Frame type
ID type
Value of lower 18 bits of ID
[ID17 to ID0]:
Message buffer number
Note
If the automatic block transmission request bit CnGMABT.ABTTRG is set to 1
in the normal operation mode with ABT, the TRQ bit is set to 1 only for one
message buffer in the ABT message buffer group.
If the TRQ bit is set to 1 for this buffer and for the message buffers that do not
belong to the ABT message buffer group, a conflict occurs. When messages
are successively transmitted from the automatic block transmission area
(message buffers 0 to 7), therefore, the priority of the transmission ID is not
searched, and the messages are transmitted sequentially, starting from the
buffer with the lowest number. However, the priority among automatic block
transmission messages and message buffers other than those in the automatic
block transmission area is in compliance with the above rule.
Upon successful transmission of a message frame, the following operations
are performed.
Preliminary User’s Manual U17566EE1V2UM00
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The TRQ flag of the corresponding transmit message buffer is
automatically cleared to 0.
The transmission completion status bit CINTS0 of the CnINTS register
is set to 1 (if the interrupt enable bit (IE) of the corresponding transmit
message buffer is set to 1).
An interrupt request signal INTRRX1 is output (if the CnIE.CIE0 bit is
set to 1 and if the interrupt enable bit (IE) of the corresponding transmit
message buffer is set to 1).
Description
The message frame with the lowest value represented by the first 11
bits of the ID is transmitted first. If the value of an 11-bit standard ID is
equal to or smaller than the first 11 bits of a 29-bit extended ID, the 11-
bit standard ID has a higher priority than a message frame with a 29-bit
extended ID.
A data frame with an 11-bit standard ID (CnMCONFm.RTR bit is
cleared to 0) has a higher priority than a remote frame with a standard
ID and a message frame with an extended ID.
A message frame with a standard ID (CnMIDHm.IDE bit is cleared to 0)
has a higher priority than a message frame with an extended ID.
If one or more transmission-pending extended ID message frame has
equal values in the first 11 bits of the ID and the same frame type (equal
RTR bit values), the message frame with the lowest value in the lower
18 bits of its extended ID is transmitted first.
If two or more message buffers request transmission of message
frames with the same ID, the message from the message buffer with the
lowest message buffer number is transmitted first.
CAN Controller (CAN)