我在设置Arduino CAN总线通信时遇到了一个奇怪的问题。
如下所述,该视频显示了结果:https://www.youtube.com/watch?v=NnMyC23Fe9s&feature=youtu.be
((注:此效果在我尝试过的每块板上都会发生)
硬件:
使用的软件:https://github.com/Seeed-Studio/CAN_BUS_Shield/blob/master/examples/send/send.ino
我从完整的设置开始,安装了2个Arduino(不是兼容的Mega,不兼容Mega)和2个CAN总线屏蔽,我想知道初始化失败了,而突然间成功了。我猜想这是关于焊接引脚的,所以我对其进行了重新设计,但并没有得到改善。
[经过大量测试,我得出了您在视频中看到的结果:我什至不需要CAN Bus Shield来初始化CAN Bus Shield O_o。如果我触摸SPI接口,它将识别我为CAN总线屏蔽。
浏览CAN BUS库时,我检查了CAN.begin函数。它使用ISP引脚(2行中的6个引脚)进行以下操作:
通过SPI读取的代码(全部从库中没有自己的代码!)
uint8_t MCP2515Class::readRegister(uint8_t address)
{
uint8_t value;
SPI.beginTransaction(_spiSettings);
digitalWrite(_csPin, LOW);
SPI.transfer(0x03);
SPI.transfer(address);
value = SPI.transfer(0x00);
digitalWrite(_csPin, HIGH);
SPI.endTransaction();
return value;
}
和CAN.begin函数
int MCP2515Class::begin(long baudRate)
{
CANControllerClass::begin(baudRate);
pinMode(_csPin, OUTPUT);
// start SPI
SPI.begin();
reset();
writeRegister(REG_CANCTRL, 0x80);
if (readRegister(REG_CANCTRL) != 0x80) {
return 0;
}
const struct {
long clockFrequency;
long baudRate;
uint8_t cnf[3];
} CNF_MAPPER[] = {
{ (long)8E6, (long)1000E3, { 0x00, 0x80, 0x00 } },
{ (long)8E6, (long)500E3, { 0x00, 0x90, 0x02 } },
{ (long)8E6, (long)250E3, { 0x00, 0xb1, 0x05 } },
{ (long)8E6, (long)200E3, { 0x00, 0xb4, 0x06 } },
{ (long)8E6, (long)125E3, { 0x01, 0xb1, 0x05 } },
{ (long)8E6, (long)100E3, { 0x01, 0xb4, 0x06 } },
{ (long)8E6, (long)80E3, { 0x01, 0xbf, 0x07 } },
{ (long)8E6, (long)50E3, { 0x03, 0xb4, 0x06 } },
{ (long)8E6, (long)40E3, { 0x03, 0xbf, 0x07 } },
{ (long)8E6, (long)20E3, { 0x07, 0xbf, 0x07 } },
{ (long)8E6, (long)10E3, { 0x0f, 0xbf, 0x07 } },
{ (long)8E6, (long)5E3, { 0x1f, 0xbf, 0x07 } },
{ (long)16E6, (long)1000E3, { 0x00, 0xd0, 0x82 } },
{ (long)16E6, (long)500E3, { 0x00, 0xf0, 0x86 } },
{ (long)16E6, (long)250E3, { 0x41, 0xf1, 0x85 } },
{ (long)16E6, (long)200E3, { 0x01, 0xfa, 0x87 } },
{ (long)16E6, (long)125E3, { 0x03, 0xf0, 0x86 } },
{ (long)16E6, (long)100E3, { 0x03, 0xfa, 0x87 } },
{ (long)16E6, (long)80E3, { 0x03, 0xff, 0x87 } },
{ (long)16E6, (long)50E3, { 0x07, 0xfa, 0x87 } },
{ (long)16E6, (long)40E3, { 0x07, 0xff, 0x87 } },
{ (long)16E6, (long)20E3, { 0x0f, 0xff, 0x87 } },
{ (long)16E6, (long)10E3, { 0x1f, 0xff, 0x87 } },
{ (long)16E6, (long)5E3, { 0x3f, 0xff, 0x87 } },
};
const uint8_t* cnf = NULL;
for (unsigned int i = 0; i < (sizeof(CNF_MAPPER) / sizeof(CNF_MAPPER[0])); i++) {
if (CNF_MAPPER[i].clockFrequency == _clockFrequency && CNF_MAPPER[i].baudRate == baudRate) {
cnf = CNF_MAPPER[i].cnf;
break;
}
}
if (cnf == NULL) {
return 0;
}
writeRegister(REG_CNF1, cnf[0]);
writeRegister(REG_CNF2, cnf[1]);
writeRegister(REG_CNF3, cnf[2]);
writeRegister(REG_CANINTE, FLAG_RXnIE(1) | FLAG_RXnIE(0));
writeRegister(REG_BFPCTRL, 0x00);
writeRegister(REG_TXRTSCTRL, 0x00);
writeRegister(REG_RXBnCTRL(0), FLAG_RXM1 | FLAG_RXM0);
writeRegister(REG_RXBnCTRL(1), FLAG_RXM1 | FLAG_RXM0);
writeRegister(REG_CANCTRL, 0x00);
if (readRegister(REG_CANCTRL) != 0x00) {
return 0;
}
return 1;
}
2个问题:
我怀疑盾牌演示程序无法正常工作,因为您尚未将盾牌插入汽车的公共汽车中。
查看屏蔽板的示意图,在屏蔽板(https://www.seeedstudio.com/CAN-BUS-Shield-V2.html)上Seeedstudio页面的“文档”选项卡下,看起来该屏蔽板是一个适配器,没有硬件对arduino讲太多。我认为需要将其插入汽车才能工作。
正如您所演示的,对于将屏蔽层插入汽车的罐总线的软件检测不是可靠的测试。
在盾牌的“学习”选项卡下,有一个到演示的链接。尽管演示视频不是英语,但您可以在https://youtu.be/Y-1AFyOP-tk?t=565处看到该板已插入汽车中。
祝您的项目万事如意!