No, the Motorola 6820 simply provides two I/O ports. The Intel 8089 is a complete processor with its own instruction set, acting as an intelligent DMA controlle

No, the Motorola 6820 simply provides two I/O ports. The Intel 8089 is a complete processor with its own instruction set, acting as an intelligent DMA controller. So you can run complex programs on the 8089 to process the I/O data. The model is kind of like the I/O channels in an IBM mainframe; you're offloading I/O tasks from the main processor to a special I/O processor.