[问答]

请问如何能利用DMA传输尽可能快地连续运行？

1871 GPIO

问答对人有帮助，内容完整，我也想知道答案 0 你好，我想用DMA来控制一些GPIO的状态。软件应将数组的条目写入PGPDO [0]寄存器。在那种情况下，我写了一个小的演示程序。 outputArray是uint16_t，包含256个元素。每个元素代表8个GPIO引脚的状态。软件应将这些元素循环写入PGPDO [0]寄存器，但它不起作用。配置看起来像这样：当我希望DMA传输尽可能快地连续运行时，有人能告诉我在配置中需要更改的内容吗？最好的祝福，帕特里克以上来自于谷歌翻译以下为原文 Hello, I would like to use DMA to control the states of some GPIOs. The software should write the entries of an array to the PGPDO[0] register. For that case, I wrote a small demo program. The outputArray is uint16_t and contains 256 elements. Each element stands for a state of 8 GPIO pins. The software should write these elements circular to the PGPDO[0] register, but it doesn´t work. The configuration looks like that: edmaChannelStart(0); edmaTCDSetWord0(edmaGetTCD(0),&outputArray); edmaTCDSetWord1(edmaGetTCD(0),1,1,2); edmaTCDSetWord2(edmaGetTCD(0),512); edmaTCDSetWord3(edmaGetTCD(0),-512); edmaTCDSetWord4(edmaGetTCD(0),&SIUL.PGPDO[0].R); edmaTCDSetWord5Linked(edmaGetTCD(0),0,0xFF,1); edmaTCDSetWord6(edmaGetTCD(0),0); edmaTCDSetWord7Linked(edmaGetTCD(0),0,0xFF,EDMA_TCD_MODE_START); Can anybody tell me what I have to change in my configuration when I want the DMA transfer to run continuously as fast as possible? Best regards, Patrik 0
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答案对人有帮助，有参考价值 0 你好，我发现了这个问题。我认为这是错误的通道配置和DMA_MUX配置的组合。以下代码使我可以将数组元素连续传输到PGPDO端口。 DAC2Table包含128个16位元素。我还能够使用PIT和触发功能触发数组元素的传输。不过，我在理解如何将DMA与其他模块一起使用时又遇到了一些问题。从参考手册中获取详细信息真的很难，而且我没有找到关于这个主题的SPC56EL的任何应用笔记。在DMA_MUX部分，我看到了使用eTimer模块作为DMA源的可能性。表173显示了eTimer_0的两个源 - Channel0和Channel1。但是，这是什么意思？什么样的请求将eTimer连接到DMA？它们是关于捕获和比较寄存器的吗？我如何将eTimer与DMA结合使用？我想要做的是在eTimer生成比较事件时触发数组元素的传输。 eTimer应该从比较加载寄存器重新加载新的比较值，然后由DMA更新。最好的祝福，帕特里克以上来自于谷歌翻译以下为原文 Hello, I have found the problem. I think it was a combination of wrong channel config and DMA_MUX config. The following code gives me a continuous transfer of the array elements to the PGPDO port. The DAC2Table contains 128 16bit elemements. DMAMUX.CHCONFIG[3].R = 0x00; DMAMUX.CHCONFIG[3].R = 0b10001110; EDMA.DMAERQL.R = 0xFFFF; edmaChannelSetup(3,&DAC2Table,&SIUL.PGPDO[0].R,2,0,1,1,2,128,-256,0,EDMA_TCD_MODE_START); I was also able to trigger the transfer of an array element using PIT and the triggered functionality. Nevertheless, I have again some problems in understanding how to use DMA with other modules. It is really hard to get detailed information out of the reference manual and I didnÂ´t found any application notes for the SPC56EL regarding this topic. In DMA_MUX section, I saw the possibility to use the eTimer module as DMA source. Table 173 shows two sources for eTimer_0 - Channel0 and Channel1. But what does this mean? What kind of request connects the eTimer to DMA? Are they regarding to the capture and compare registers? And how do I use the eTimer in combination with DMA? What I want to do is to trigger the transfer of an array element when the eTimer produces a compare event. The eTimer should reload the load the new compare value from the compare load register, which should then be updated by DMA. Best regards, Patrik

2019-6-4 12:07:58 评论举报杨帆