SAM4E-EK开发板代码解读04——CAN

Mcuzone_TKN

关键词：Microchip Atmel  SAM4E SAM4E-EK  SAM4E16E 芯片CAN 控制器局域网络

概述：实现板载两路之间的收发

开发板有两路CAN，每个CAN有8个信箱。CAN总线上的逻辑数值是用显性电平和隐性电平表示，显性是指在同时传输显性电平和隐性电平时，总线上呈现的是显性电平。显性电平表示逻辑0，隐性电平表示逻辑1。

打开产品光盘SAM4E16E-EK/SAM4E16E-EK中文资料/softpack软件包/Atmel Studio 7,打开03_CAN_EXAMPLE例子。

int main(void)
{
uint32_t ul_sysclk;
uint8_t uc_char;

sysclk_init();
board_init();

configure_console();
//输出示例信息
puts(STRING_HEADER);
//初始化CAN0收发信机
sn65hvd234_set_rs(&can0_transceiver, PIN_CAN0_TR_RS_IDX);
sn65hvd234_set_en(&can0_transceiver, PIN_CAN0_TR_EN_IDX);
//启用CAN0收发信机
sn65hvd234_disable_low_power(&can0_transceiver);
sn65hvd234_enable(&can0_transceiver);
/初始化CAN1收发信机/
sn65hvd234_set_rs(&can1_transceiver, PIN_CAN1_TR_RS_IDX);
sn65hvd234_set_en(&can1_transceiver, PIN_CAN1_TR_EN_IDX);
//使能CAN1收发信机
sn65hvd234_disable_low_power(&can1_transceiver);
sn65hvd234_enable(&can1_transceiver);
//使能CAN0和CAN1时钟
pmc_enable_periph_clk(ID_CAN0);
pmc_enable_periph_clk(ID_CAN1);
ul_sysclk = sysclk_get_cpu_hz();
if (can_init(CAN0, ul_sysclk, CAN_BPS_1000K) &&
  can_init(CAN1, ul_sysclk, CAN_BPS_1000K)) {
  puts("CAN initialization is completed." STRING_EOL);
  //关闭CAN0和CAN1的中断
  can_disable_interrupt(CAN0, CAN_DISABLE_ALL_INTERRUPT_MASK);
  can_disable_interrupt(CAN1, CAN_DISABLE_ALL_INTERRUPT_MASK);
  //配置并启用CAN1的中断
NVIC_EnableIRQ(CAN1_IRQn);
  //运行测试
  puts("Press any key to start test" STRING_EOL);
  while (uart_read(CONSOLE_UART, &uc_char)) {
  }
  test_1();
  g_ul_recv_status = 0;
  puts("Press any key to continue..." STRING_EOL);
  while (uart_read(CONSOLE_UART, &uc_char)) {
  }
  test_2();
  g_ul_recv_status = 0;
  puts("Press any key to continue..." STRING_EOL);
  while (uart_read(CONSOLE_UART, &uc_char)) {
  }
  test_3();
  g_ul_recv_status = 0;
  puts("Press any key to continue..." STRING_EOL);
  while (uart_read(CONSOLE_UART, &uc_char)) {
  }
  test_4();
  g_ul_recv_status = 0;
  //关闭CAN0
can_disable(CAN0);
  //关闭CAN0收发信机
  sn65hvd234_enable_low_power(&can0_transceiver);
  sn65hvd234_disable(&can0_transceiver);
  //关闭CAN1
  can_disable(CAN1);
  //关闭CAN1收发器
  sn65hvd234_enable_low_power(&can1_transceiver);
  sn65hvd234_disable(&can1_transceiver);
  puts("End of all tests" STRING_EOL);
} else {
  puts("CAN initialization (sync) ERROR" STRING_EOL);
}
while (1) {
}
}

Mcuzone_TKN

1. static void test_1(void)
   
2. {
   
3.         can_reset_all_mailbox(CAN0);
   
4.         can_reset_all_mailbox(CAN1);
   
5. 
   
6.         puts("\n\rTest1: CAN0 Mailbox 0 transmitting to CAN1 Mailbox 0" STRING_EOL);
   
7. 
   
8.          //初始化CAN1邮箱0到接收邮箱
   
9.         reset_mailbox_conf(&can1_mailbox);
   
10.         can1_mailbox.ul_mb_idx = TEST1_CAN_COMM_MB_IDX;
    
11.         can1_mailbox.uc_obj_type = CAN_MB_RX_MODE;
    
12.         can1_mailbox.ul_id_msk = CAN_MAM_MIDvA_Msk | CAN_MAM_MIDvB_Msk;
    
13.         can1_mailbox.ul_id = CAN_MID_MIDvA(TEST1_CAN_TRANSFER_ID);
    
14.         can_mailbox_init(CAN1, &can1_mailbox);
    
15. 
    
16.        
    
17.         //初始化CAN0邮箱0来传输邮箱
    
18.         reset_mailbox_conf(&can0_mailbox);
    
19.         can0_mailbox.ul_mb_idx = TEST1_CAN_COMM_MB_IDX;
    
20.         can0_mailbox.uc_obj_type = CAN_MB_TX_MODE;
    
21.         can0_mailbox.uc_tx_prio = TEST1_CAN0_TX_PRIO;
    
22.         can0_mailbox.uc_id_ver = 0;
    
23.         can0_mailbox.ul_id_msk = 0;
    
24.         can_mailbox_init(CAN0, &can0_mailbox);
    
25. 
    
26.        
    
27.         //写发送信息到邮箱
    
28.         can0_mailbox.ul_id = CAN_MID_MIDvA(TEST1_CAN_TRANSFER_ID);
    
29.         can0_mailbox.ul_datal = CAN_MSG_TOGGLE_LED_0;
    
30.         can0_mailbox.ul_datah = CAN_MSG_DUMMY_DATA;
    
31.         can0_mailbox.uc_length = MAX_CAN_FRAME_DATA_LEN;
    
32.         can_mailbox_write(CAN0, &can0_mailbox);
    
33. 
    
34.        
    
35.         //使能CAN1邮箱0中断
    
36.         can_enable_interrupt(CAN1, CAN_IER_MB0);
    
37. 
    
38.        
    
39.         //把邮箱里的信息发出去
    
40.         can_global_send_transfer_cmd(CAN0, CAN_TCR_MB0);
    
41. 
    
42.         while (!g_ul_recv_status) {
    
43.         }
    
44. 
    
45.         if ((can1_mailbox.ul_datal == CAN_MSG_TOGGLE_LED_0) &&
    
46.                 (can1_mailbox.uc_length == MAX_CAN_FRAME_DATA_LEN)) {
    
47.                 puts("Test1 passed" STRING_EOL);
    
48.                 decode_can_msg(&can1_mailbox);
    
49.         } else {
    
50.                 puts("Test1 ERROR" STRING_EOL);
    
51.         }
    
52. }

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