uart dma单次发送的最长字节

[SSFG1992]

平台 ：imxrt1064

1064的SDK中有uart_DMA发送的例程，我看到LPUART_SendEDMA函数里面是使用的minorloop是1，majorloop等于要发送的字节数。edma的majorloop最大值是32767，这样单次发送的最大字节数是不是被限制为32767？

如果使用majorloop=1，minorloop=要发送的字节数，最大发送长度会大很多。请问如何修改sdk中的驱动代码？

我把LPUART_SendEDMA函数中的EDMA_PrepareTransfer函数的bytesEachRequest参数从sizeof（uint8_t）修改成xfer->dataSize，这样好像不行。请教正解！！

[jeremyzhou]

Hi,
非常感谢使用NXP产品，很高兴为你提供技术支持！
对于LPUART_SendEDMA()采用Single request模式，当DMA request产生后，UART可以传输的最多字节由NBYTES位决定，具体请先浏览一下RM中的6.5.4.1 Single reque章节。
Have a great day,
TIC

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