topic Using DMA with eTPU UARTs in ColdFire/68K Microcontrollers and Processors https://community.nxp.com/t5/ColdFire-68K-Microcontrollers/Using-DMA-with-eTPU-UARTs/m-p/383139#M12437 <HTML><HEAD></HEAD><BODY><P>Hello,</P><P style="min-height: 8pt; padding: 0px;">&nbsp;</P><P>I am considering using DMA to transfer data for an eTPU UART interrupt on a MCF5233 processor.&nbsp; I am wondering if there are any code examples to do this, or any code examples using DMA with the eTPU at all.</P><P style="min-height: 8pt; padding: 0px;">&nbsp;</P><P>Specifically, I am wondering if there is a reliable way to use DMA on more than one channel at once since all eTPU interrupts are OR'ed together to one DMA request to DMA controller 3.&nbsp; With one eTPU channel using DMA, you can set the DMA source register to the relevant address in SRAM with data for that channel and it is no problem.&nbsp; If multiple channels use DMA, then you could set the DMA source register to a block of RAM that includes the data for all of the channels, but I can't find a way to tell which channel generated the DMA request.&nbsp; You could look at the DTRS bits to see which channels have generated a request, but I think that could lead to race conditions where the DMA transfers the data from SRAM before you have a chance to read DTRS.&nbsp; Is there a solution for this or is it recommended to only use DMA for one eTPU channel?</P></BODY></HTML> Mon, 01 Dec 2014 11:38:27 GMT tmelm 2014-12-01T11:38:27Z Using DMA with eTPU UARTs https://community.nxp.com/t5/ColdFire-68K-Microcontrollers/Using-DMA-with-eTPU-UARTs/m-p/383139#M12437 <HTML><HEAD></HEAD><BODY><P>Hello,</P><P style="min-height: 8pt; padding: 0px;">&nbsp;</P><P>I am considering using DMA to transfer data for an eTPU UART interrupt on a MCF5233 processor.&nbsp; I am wondering if there are any code examples to do this, or any code examples using DMA with the eTPU at all.</P><P style="min-height: 8pt; padding: 0px;">&nbsp;</P><P>Specifically, I am wondering if there is a reliable way to use DMA on more than one channel at once since all eTPU interrupts are OR'ed together to one DMA request to DMA controller 3.&nbsp; With one eTPU channel using DMA, you can set the DMA source register to the relevant address in SRAM with data for that channel and it is no problem.&nbsp; If multiple channels use DMA, then you could set the DMA source register to a block of RAM that includes the data for all of the channels, but I can't find a way to tell which channel generated the DMA request.&nbsp; You could look at the DTRS bits to see which channels have generated a request, but I think that could lead to race conditions where the DMA transfers the data from SRAM before you have a chance to read DTRS.&nbsp; Is there a solution for this or is it recommended to only use DMA for one eTPU channel?</P></BODY></HTML> Mon, 01 Dec 2014 11:38:27 GMT https://community.nxp.com/t5/ColdFire-68K-Microcontrollers/Using-DMA-with-eTPU-UARTs/m-p/383139#M12437 tmelm 2014-12-01T11:38:27Z