5.3 DMA level

Jumper block J7 contains pins for selecting the DMA level between channels 1 and 3. To select channel, 1 both jumpers labeled “1” must be on. To select channel 3, both jumpers labeled “3” must be on. DMA is supported in the hardware, however it is not currently supported in Diamond Systems’ Universal Driver software. On boards without FIFOs or memory buffers, DMA is required to support high-speed sampling at rates above the maximum sustainable interrupt rate, which may vary from 1,000 to 20,000 depending on the CPU and operating system. However, DMM-32DX-AT contains a 1024-sample FIFO for A/D data that allows the interrupt rate to be much slower than the sample rate. The board can support full-speed sampling at up to 250,000 samples per second without the use of DMA.