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CHAPTER 22 CAN CONTROLLER
immediately after setting TXRQST = "1", but after any of the following events:
1. there is activity ongoing on the CANbus
2. a transmission request is issued on another message object
3. the CANbus is initialized by the INIT bit
In general, there is no need to cancel an ongoing transmission by setting TXRQST = 0. If the content of a
message object needs to be changed while TXRQST = 1, it is sufficient to update the message object via
the CPU interface registers (Identifier, DLC, Data, with TXRQST and NEWDAT, optionally TXIE). The
updated content will be transmitted at the next opportunity.
If more than 32 message buffers are implemented, the following table gives an overview about the additional
flags:
Table 22.8-1 Additional flags when more than 32 message buffers exist
TREQR 4 & 3
TXRQST 64-33 (address 0x84)
TREQR 6 & 5
TXRQST 96-65 (address 0x88)
TREQR 8 & 7
TXRQST 128-97 (address 0x8C)
614
addr+0
addr+1
TXRQST64-57
TXRQST56-49
TXRQST96-89
TXRQST88-81
TXRQST128-121
TXRQST120-113
MB96300 Super Series Hardware Manual
addr+2
addr+3
TXRQST48-41
TXRQST40-33
TXRQST80-73
TXRQST72-65
TXRQST112-105
TXRQST104-97
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