原创 PIC18Fxx8之CAN发送优先级

1_002： 发送优先级

发送优先级是对PIC18Fxx8器件内的可发送信息进行优先级排序。它区别于建立在CAN协议中固有信息仲裁方案的优先级。在发送SOF之前，对所有用于发送的缓冲区优先级进行比较。具有最高优先级的发送缓冲器将先发送。如果两个缓冲区拥有同样的地优先级，则缓冲区序号高的那个缓冲区先发送。总共有4级发送优先级， 11=3级优先级（最高），10=2级优先级，01=1级优先级，00=0级优先级（最低）。

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TRANSMIT PRIORITY
Transmit priority is a prioritization within the PIC18FXX8 of the pending transmittable messages. This is independent from, and not related to, any prioritization implicit in the message arbitration scheme built into the CAN protocol. Prior to sending the SOF, the priority
of all buffers that are queued for transmission is compared. The transmit buffer with the highest priority will be sent first. If two buffers have the same priority setting, the buffer with the highest buffer number will be sent first. There are four levels of transmit priority. If TXP bits for a particular message buffer are set to ‘11’, that buffer has the highest possible priority. If TXP bits for a particular message buffer are ‘00’, that buffer has the lowest possible priority.