Abstract: A fuzzy inference engine (10) performs fuzzy logic operations with a high degree of accuracy in a minimal amount of time. The fuzzy inference engine (10) includes a fuzzification module (12) which decodes an input signal to access a memory location (18, 20). When accessed, the memory location provides a unary value to a rule evaluation module (26). The rule evaluation module (26) subsequently processes the unary value to indicate a relative strength of a fuzzy inference rule. Because the fuzzy logic operations use unary numbers, rather than more traditional binary numbers, the only time required to perform fuzzy logic operations is equal to only a time required for the signal to propagate through the logic gates (28, 30, 32, 34, 36, and 38) forming rule evaluation module (26).

Abstract: A data processor (50) includes a hardware keyscan circuit (54) to interface to an external keypad matrix (80). In one embodiment, the data processor (50) has a first register (62) for driving data to rows of the keypad matrix (80), and a second register (63) for inputting signals from columns of the keypad matrix (80). A set of weak pullup elements (71) connected to the columns is always conductive. A set of strong pullup elements (75) connected to the columns is conductive only after the hardware keyscan circuit (54) detects that a key (89) is depressed and disables the driving of the rows. Thus, pullup time and power consumption are minimized. The hardware keyscan circuit (54) also includes a data direction register (61) which has a shift control input terminal so that in response to a local state machine (64), the data direction register (61) acts as a shift register to sense the row with the depressed key (89), without intervention from a central processing unit (51).