把CAN通信线拔掉，MPU的CAN口一直有波形输出

everkimage · 发表于 2018-9-10 09:20:45

本帖最后由 everkimage 于 2018-9-10 09:26 编辑

芯片是KEA128，程序里CAN发送放在中断里，在程序某个地方关闭中断，然后跑入一段死循环，拔掉CAN通信线，CAN口一直会有波形输出，但不是每次都这样。
尝试过将MSCAN.CANCTL.CANE置零，将MSCAN.CANCTL.LOOPB置一，CAN口依然有波形输出。
这是硬件BUG还是CAN通信协议本身的功能所致，比如等待回复或发送回复？如何关闭这种输出？

我知道答案目前已有6人回答

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小恩GG · 发表于 2018-9-10 11:50:49

你用的是什么代码？是官方代码吗？
还有，在什么情况触发了上述的现象呢？

everkimage · 发表于 2018-9-10 13:37:08

初始化调用的库函数，不过是否官方可能与这个现象没关系。
因为板子有CAN信号唤醒，所以如果在关机的时候有CAN信号，则立刻会被唤醒。出现这种现象大概流程是这样的：
1.按键关机；
2.发现系统复位，拔掉CAN通信线，再按键关机；
3.偶尔会再复位；
于是把关机函数写成这样：
1.关闭中断（CAN数据在时钟中断里发出）；
2.清除CANE位；
3.关闭电源；
4.死循环；
结果偶尔还是出现关不了机（电源灯亮），因为是死循环，所以就去量了CAN_RX,CAN_TX引脚，TX有波形。这个时候软件在死循环，中断关闭了，所以CAN信号不可能是软件发出的。

everkimage · 发表于 2018-9-10 13:38:01

初始化调用的库函数，不过是否官方可能与这个现象没关系。
因为板子有CAN信号唤醒，所以如果在关机的时候有CAN信号，则立刻会被唤醒。出现这种现象大概流程是这样的：
1.按键关机；
2.发现系统复位，拔掉CAN通信线，再按键关机；
3.偶尔会再复位；
于是把关机函数写成这样：
1.关闭中断（CAN数据在时钟中断里发出）；
2.清除CANE位；
3.关闭电源；
4.死循环；
结果偶尔还是出现关不了机（电源灯亮），因为是死循环，所以就去量了CAN_RX,CAN_TX引脚，TX有波形。这个时候软件在死循环，中断关闭了，所以CAN信号不可能是软件发出的。

everkimage · 发表于 2018-9-10 13:38:32

小恩GG 发表于 2018-9-10 11:50
你用的是什么代码？是官方代码吗？
还有，在什么情况触发了上述的现象呢？ ...

初始化调用的库函数，不过是否官方可能与这个现象没关系。
因为板子有CAN信号唤醒，所以如果在关机的时候有CAN信号，则立刻会被唤醒。出现这种现象大概流程是这样的：
1.按键关机；
2.发现系统复位，拔掉CAN通信线，再按键关机；
3.偶尔会再复位；
于是把关机函数写成这样：
1.关闭中断（CAN数据在时钟中断里发出）；
2.清除CANE位；
3.关闭电源；
4.死循环；
结果偶尔还是出现关不了机（电源灯亮），因为是死循环，所以就去量了CAN_RX,CAN_TX引脚，TX有波形。这个时候软件在死循环，中断关闭了，所以CAN信号不可能是软件发出的。

小恩GG · 发表于 2018-9-11 09:50:24

everkimage 发表于 2018-9-10 13:38
初始化调用的库函数，不过是否官方可能与这个现象没关系。
因为板子有CAN信号唤醒，所以如果在关机的时候 ...

你能分享一个简单的可还原问题的代码吗，最好基于官方例程的

everkimage · 发表于 2018-9-11 10:27:33

初始化：

MSCAN_ParametersConfig CAN_Module_Config;
MSCAN_FilterConfigure CAN_Filter_Config;
CAN_Module_Config.baudrate = MSCAN_Baudrate_250K; /* Baud rate 250Kbps */
CAN_Module_Config.MSCAN_SignalPinsRemap = 0; /* MSCAN signal pins remap on PTC7(TX) and PTC6(RX) */
CAN_Module_Config.MSCAN_StopInWaitMode = 1; /* MSCAN module is normal in wait mode */
CAN_Module_Config.MSCAN_TimeStampEnable = 0; /* Disable internal MSCAN timer stamp */
CAN_Module_Config.MSCAN_WakeUpEnable = 0; /* Wake-up disabled */
CAN_Module_Config.MSCAN_LoopbackMode = 0; /* Loop back self test disabled */
CAN_Module_Config.MSCAN_ListenOnlyMode = 0; /* Normal operation */
CAN_Module_Config.MSCAN_BusoffRecoveryMode = 0; /* Automatic bus-off recovery */
CAN_Module_Config.MSCAN_WakeUpMode = 0; /* Wakes up on any dominant level on CAN bus */
CAN_Module_Config.MSCAN_WakeUpINTEnable = 0; /* Wake-up interrupt disable */
CAN_Module_Config.MSCAN_OverrunINTEnable = 0; /* Overrun interrupt disable */
CAN_Module_Config.MSCAN_ReceiveFullINTEnable = 1; /* Receive full interrupt enable */
CAN_Module_Config.MSCAN_TransEmptyINTEnable = 0; /* Transmitter empty interrupt disable */
CAN_Filter_Config.Filter_Enable = 1; /* Enable CAN module filters. If this value is cleared,the following parameters does not work */
CAN_Filter_Config.Filter_Channel = 0; /* Select CAN module filter channel 0 */
CAN_Filter_Config.frame_type = OnlyAcceptDataFrame; /* Enable CAN filter just receive data frame */
CAN_Filter_Config.id_format = OnlyAcceptExtendedID; /* Enable CAN filter just receive extended ID */
CAN_Filter_Config.id_mask = 0xFFFFFFFFu; /* When this value is set to 0xFFFFFFFFu,the id_accept value does not work */
CAN_Filter_Config.id_accept = 0x18901212u; /* Because the id_mask value has been set to 0xFFFFFFFFu,id_accept does not work and can be set to any value */
(void)MSCAN_Init(&CAN_Module_Config, &CAN_Filter_Config); /* Call MSCAN_Init function to initialize MSCAN module by specified properties */
Set_Vector_Handler(MSCAN_RX_VECTORn, MSCAN_RX_Handler); /* Specify MSCAN receive data irq handler function name */
NVIC_EnableIRQ(MSCAN_RX_IRQn); /* Enable MSCAN receive data NVIC interrupt */
NVIC_SetPriority(MSCAN_RX_IRQn, 0); /* Set MSCAN_RX interrupt priority to 0(The highest). */

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发送：

uint8_t reg_val, i;
uint8_t temp1, temp2, temp3;
if (W_Framebuff != NULL)
{
/* Ensure the length of the data not to be greater than 8 bytes. */
if (W_Framebuff->data_length > 8)
{
return -1;
}
/* Ensure there is at least one Empty Transmission Buffer. */
if ((reg_val = (MSCAN->CANTFLG & MSCAN_CANTFLG_TXE_MASK)) == 0)
{
return -1;
}
/*
* According to the KEAZ128RM, select the Empty Transmission Buffer
* by passing the value of CANx->CANTFLG to CANx->CANTBSEL. NOTICE,
* after doing this, the value of CANx->CANTBSEL will be the index
* of the Empty Transmission Buffer been selected.
*/
MSCAN->CANTBSEL = reg_val;
if ((W_Framebuff->frame_type == RemoteFrameWithStandardId)
|| (W_Framebuff->frame_type == DataFrameWithStandardId))
{
/* indicate the frame is standard format */
MSCAN->TSIDR1 &= ~MSCAN_TSIDR1_TSIDE_MASK;
/* If caller wants to send a packet with standard id, firstly
* ensure the id not to be exceed 11 bits.
*/
if (W_Framebuff->frame_id > 0x7FFu)
{
return -1;
}
/* Load the id into the respective registers. */
MSCAN->TSIDR0 = (uint8_t)(W_Framebuff->frame_id >> 3);
MSCAN->TSIDR1 = (uint8_t)(W_Framebuff->frame_id << 5);
if (W_Framebuff->frame_type == RemoteFrameWithStandardId)
{
/*
* If caller wants to send a remote packet, set the
* respective bit in CANx->SIDR1, and set the TDLR
* to be 0 (the remote packet has no data).
*/
MSCAN->TSIDR1 |= MSCAN_TSIDR1_TSRTR_MASK;
/* The data length should be 0 */
MSCAN->TDLR = 0;
}
else
{
MSCAN->TSIDR1 &= ~MSCAN_TSIDR1_TSRTR_MASK;
/*
* If caller wants to send a data packet, set the
* TDLR to be equal to the actual data length
*/
MSCAN->TDLR = W_Framebuff->data_length;
/* Load the actual data to the Transmit Extended Data Segment Register */
for (i = 0; i < W_Framebuff->data_length; i++)
{
MSCAN->TEDSR[i] = W_Framebuff->data[i];
}
}
}
else if ((W_Framebuff->frame_type == RemoteFrameWithExtendedId)
|| (W_Framebuff->frame_type == DataFrameWithExtendedId))
{
/* When caller wants to send a frame with ExtendedID,
* the TEIDE bit of MSCAN_TEIDR1 register should be set to 1 */
MSCAN->TEIDR1 = MSCAN_TEIDR1_TEIDE_MASK;
/* If caller wants to send a packet with standard id, firstly
* ensure the id not to be exceed 29 bits.
*/
if (W_Framebuff->frame_id > 0x1FFFFFFF)
{
return -1;
}
MSCAN->TEIDR0 = (uint8_t)((W_Framebuff->frame_id) >> 21);
temp1 = (uint8_t)((W_Framebuff->frame_id) >> 18) & 0x07;
temp2 = (uint8_t)((W_Framebuff->frame_id) >> 15) & 0x07;
/* Attention:The TSRR bit is used only in extended format.
* It must be set to 1 by the user for transmission buffers
*/
MSCAN->TEIDR1 |= (temp1 << 5) | temp2 | MSCAN_TEIDR1_TSRR_MASK;
MSCAN->TEIDR2 = (uint8_t)((W_Framebuff->frame_id) >> 7);
temp3 = (uint8_t)W_Framebuff->frame_id & 0x7Fu;
MSCAN->TEIDR3 = MSCAN_TEIDR3_TEID6_TEID0(temp3);
if (W_Framebuff->frame_type == RemoteFrameWithExtendedId)
{
MSCAN->TEIDR3 |= MSCAN_TEIDR3_TERTR_MASK;
MSCAN->TDLR = 0;
}
else
{
MSCAN->TEIDR3 &= ~MSCAN_TEIDR3_TERTR_MASK;
MSCAN->TDLR = W_Framebuff->data_length;
for (i = 0; i < W_Framebuff->data_length; i++)
{
MSCAN->TEDSR[i] = W_Framebuff->data[i];
}
}
}
else
{
return -1;
}
/*
* The purpose is to clear the respective bit,
* according to the KEAZ128RM, it should be done
* by writing 1 but not 0.
*/
MSCAN->CANTFLG = MSCAN->CANTBSEL;
return 0;
}
return -1;

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[求助] 把CAN通信线拔掉，MPU的CAN口一直有波形输出

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