doreadme.txt

来自「mc9s12dg128freescale16位单片机can控制程序」· 文本 代码 · 共 27 行

    /* University Board Uses PH1 to enable CAN Transceiver U13 */
    /* U13 is the transceiver for Port 0 */
    /*	CON3 Pinout:
    		CAN1L -> Pin1
    		CAN1H -> Pin2
    		CAN0L -> Pin3
    		CAN0H -> Pin4	*/
   	/* University Board has 8MHz clock source */
   	/* Jumper J8 (BDM +5V) should be connected */
/* CAN Clock Source (External oscillator) = 8Mhz
 * Target BitRate = 125Khz 
 * Total Time Quanta = 16
 * Sincronization Jump Width = 4 Time Quanta
 * 1 sample
 * Sample point at 75% of Bit Timing
 *
 * CAN_BRP = ((CAN Clock Source)/fTq) - 1
 * fTq = (Bit Rate) * (Total Time Quanta)
 * Total Time Quanta = (SYNCH_SEG+(TSEG1+1)+(TSEG2+1))          
 * Total Time Quanta =      1    +    11   +    4     = 16 Time Quanta
 * fTq = 125Khz * 16 Time Quanta = 2Mhz
 * CAN_BRP = (16Mhz/2Mhz) - 1 = 8 - 1 = 7 
 * TSEG1 = 10
 * TSEG2 = 3
 * SJW = (Synchronization Jump Width-1) = 3        
 */