RTOS/MSP430F5529: How to allocate dma(0-2) channels to usci peripheral

Tool/software: TI-RTOS

Hi everyone

        I learned that MSP430F5529 has only three DMA(0-2) channels today.  but under TI-RTOS, the SPI module library default uses DMA.

        Now I had config two spis, one for the master and the other for the slave. when spiA1 and spiB1 both use DMA_CHANNEL_1(RX) and DMA_CHANNEL_1(TX). when I used the SPI_transfer() function to send and receive in the two TASK, I found that they were interfering with each other, resulting in data confusion.  this issue I've described before. It's the link()   

        now I configure two spi to use different dma channels, but I only have three dma channels, at least one DMA channel is shared by two SPI, which does not consider ADC and other peripherals to use DMA.  What can I do to avoid this problem? using semaphores? or spi not use DMA?   Who can give some advice or examples?  Because I'm going to use 4 spi and 10 ADCs on MSP430F5259 next.

best regards

xc.mo

1.consult

2.my spi config example