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参考 \TVII_Sample_Driver_Library_7.2.0\tviibe1m\src\examples\scb\spi\Low_level_driver_master示例,基于CYTVII-B-E-1M-SK 验证SPI通信,发现每次发送数据时,MOSI在片选信号CS有效前就会改变电平状态,跟TRM所示的通信时序图有差异,如下图所示:
CH2: Slave select,CH4: CLK,CH1: MOSI
为什么MOSI在SS拉低前就改变了PIN脚状态?
SCB配置信息如下:
static const cy_stc_scb_spi_config_t SCB_SPI_cfg =
{
.spiMode = CY_SCB_SPI_MASTER,
.subMode = CY_SCB_SPI_MOTOROLA,
.sclkMode = CY_SCB_SPI_CPHA1_CPOL0,
.oversample = SCB_SPI_OVERSAMPLING,
.rxDataWidth = 8ul,
.txDataWidth = 8ul,
.enableMsbFirst = true,
.enableFreeRunSclk = false,
.enableInputFilter = true,
.enableMisoLateSample = false,
.enableTransferSeperation = false,
.ssPolarity0 = false,
.ssPolarity1 = false,
.ssPolarity2 = false,
.ssPolarity3 = false,
.enableWakeFromSleep = false,
.rxFifoTriggerLevel = 1ul,
.rxFifoIntEnableMask = 1ul,
.txFifoTriggerLevel = 0ul,
.txFifoIntEnableMask = 0ul,
.masterSlaveIntEnableMask = 0ul,
.enableSpiDoneInterrupt = false,
.enableSpiBusErrorInterrupt = false,
};
Solved! Go to Solution.
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Automotive Traveo_II
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此差异是因为TVII 的SPI 硬件逻辑如此(片选之前提前一些就送出数据)而传统的SPI逻辑是片选之后才送。
通常TVII SPI 这样应会正常通讯,如果你测试与SPI slave 通讯有什么问题可以发上来看看 🤔
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此差异是因为TVII 的SPI 硬件逻辑如此(片选之前提前一些就送出数据)而传统的SPI逻辑是片选之后才送。
通常TVII SPI 这样应会正常通讯,如果你测试与SPI slave 通讯有什么问题可以发上来看看 🤔
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Roy;
感谢你的答复,的确,TVII SPI通信没有问题,只是此处波形与常用SPI有差异,才有此疑问;
另,你所提到的硬件逻辑(片选之前发送一些数据),在TRM或AN上有提到吗?还是默认TVII如此?
谢谢~~
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好像TRM或AN 都没有提及,默认TVII 就如此。不过后续我们会考虑做个knowledge base article发布在此论坛。
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明白,感谢你的回复🤝
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应该的,互相交流学习🙂
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Hi Roy;
换言之,PSoC和TraveoII 的SCB模块IP是一致的,可以相互参考和验证。
感谢你的支持!!
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对头 😁
非常乐意提供支持