Protocol Conversion from Max Mode to Min Mode
Original Publication Date: 1982-Jun-01
Included in the Prior Art Database: 2005-Feb-09
The Intel 8088 and 8086 microprocessors are designed for two modes of operation: maximum mode and minimum mode. These modes are selected by strapping a module pin high or low. In the minimum mode, the microprocessor allows the attachment of standard Direct Memory Access (DMA) devices, such as the Intel 8237 and 8257, by using the familiar HOLD/HOL:DA Protocols. This allows the use of a wide variety of input/output device attachment chips which use the standard DMA device interface. The major problem of the minimum mode operation is that it does not allow co-processor operation, this function is available only in the maximum mode.