In this organization all modules share the same system bus.The DMA module here acts as a surrogate processor. This method uses programmed I/O to exchange data between memory and an I/O module through the DMA module.

For each transfer it uses the bus twice. The first one is when transferring the data between I/O and DMA and the second one is when transferring the data between DMA and memory. Since the bus is used twice while transferring data, so the bus will be suspended twice. The transfer consumes two bus cycle.

The interconnection organization is shown in the Figure 6.11.

Figure 6.11: Single bus arrangement for DMA transfer