1. A block of 16-bit stereo audio data having the size of 4551792 bytes is transferred via I2S interface configured in DMA mode with 16-bit data width and DMA interrupts enabled. The sampling frequency is 44.1 kHz. Determine the maximum amount of data (total number of samples) per DMA transfer to implement playback so that all DMA transfers have the same size. Determine the time interval between DMA Transfer Complete Interrupts.
To determine the maximum amount of data per DMA transfer, we first need to calculate the total number of samples in the audio data block:
Total number of bytes = 4551792 bytes
Data width = 16 bits = 2 bytes
Total number of samples = Total number of bytes / Data width
Total number of samples = 4551792 bytes / 2 bytes
Total number of samples = 2275896 samples
Since we want all DMA transfers to have the same size, we need to find a common factor for both the total number of samples and the maximum amount of data per DMA transfer. One common factor for 2275896 is 4:
Total number of samples = 2275896 samples
Maximum amount of data per DMA transfer = 2275896 / 4 samples
Maximum amount of data per DMA transfer = 568974 samples
Next, we need to determine the time interval between DMA Transfer Complete Interrupts. Since the sampling frequency is 44.1 kHz, the time interval can be calculated as follows:
Time interval = (Maximum amount of data per DMA transfer / Sampling frequency)
Time interval = 568974 samples / 44100 samples per second
Time interval ≈ 12.879 seconds
Therefore, the maximum amount of data per DMA transfer is 568974 samples, and the time interval between DMA Transfer Complete Interrupts is approximately 12.879 seconds.