I am trying to use the DMA to control data transfers to/from a UART on the MCF5441x, but it is not working. I got the Rev. 3 reference manual, which fills in the missing information of the Rev 4 manual. I thought that I had everything set up correctly, but the DMA channel never starts. On a transmit attempt, it appears that the channel receives the DMA Request from the UART (per the HRS register), but it never does anything. ERQ is enabled for the channel and there are no error flags. Even if I explicitly set the start bit, the channel never starts (the start bit stays 1). I attached snippets from the code that do the initialization and initiate a test transfer. Can anyone help?
Original Attachment has been moved to: UART-DMA-control-code.txt.zip