I'm having some issues transferring values from a 16 bit sine wave lookup table to a 16 bit shift register using DMA. My problem is that the shift register properly shifts out the MSB, but shifts out a constant value for the LSB. As a test I wrote to the shift register from the CPU and everything worked fine. I followed the instructions on the "Advanced DMA Topics" application note to ensure that the source and destination are aligned properly, but I still can get all 16 bits transferred. Any ideas what can be causing this?
Can you post your complete project, so that we all can have a look at all of your settings? To do so, use Creator->File->Create Workspace Bundle (minimal) and attach the resulting file.
I tried using ShiftReg_1_OUT_FIFO_VAL_LSB_PTR, but it still doesn't work the shift register outputs the same value for every sample. I use "ShiftReg_1_IN_FIFO_VAL_LSB_PTR" as its used in the ShiftReg_1.c to write data to be shifted out.
What would cause the following error when trying to open the project referenced in this thread?
Errors found while loading "C:\Users\rtb\Desktop\Cypress Projects\AN52705\Eg3_Mem_DMA_DAC.cydsn\TopDesign\TopDesign.cysch" file. This file would not be considered in the update process.
I started a support case and was able to fix my problem. The solution from the support engineer was this:
"You will need to use the destination address as "Shift_Register_bSR_sC16_BShiftRegDp_u0__16BIT_A0_REG" rather than "Shift_Register_SHIFT_REG_LSB_PTR". The 16 bit pointer "Shift_Register_bSR_sC16_BShiftRegDp_u0__16BIT_A0_REG" should have been generated in the header file, but it is not. It is a defect. We have notified this to the software team and they will fix it."
