摘要:
Method and apparatus for performing multiplexed and non-multiplexed bus cycles in a data processing system (10). The present invention allows a data processing system (10) to switch from multiplexed bus cycles to non-multiplexed bus cycles, and vice-versa, without requiring the data processing system (10) to be reset. In one embodiment of the present invention, a single user programmable control bit (90) is used to select whether an external bus cycle will be multiplexed or non-multiplexed. In more complex embodiments of the present invention, the ability to switch between multiplexed external bus cycles and non-multiplexed external bus cycles may be achieved by way of a plurality of user programmable register fields (96, 100, 102, and 104) located in registers 44. The plurality of user programmable register fields (96, 100, 102, and 104) may be associated with one or more chip select signals.
摘要:
Method and apparatus in a data processing system (10) for selectively inserting bus cycle idle time. The present invention allows a data processing system (10) to selectively insert a predetermined number of idle clocks at the end of a bus cycle. In one embodiment of the present invention, there is a base register (48) and an option register (46) corresponding to each one of the chip select terminals (73). In one embodiment of the present invention, each option register (46) includes a user programmable idle control bit (110). If a first chip select is used to select a peripheral device during a bus cycle to that same peripheral device, the idle control bit (110) which corresponds to the first chip select determines whether or not one or more idle clocks will be inserted after that bus cycle.
摘要:
A block erasable flash EEPROM (22) having a single array (68) which can be partitioned into one or more blocks (50-57). The same column decode/block select circuitry (66) is used to provide both column select signals (71) and block select signals (73). The number of blocks (50-57) and the size of each block (50-57) can be determined by the manufacturer during the manufacturing process. Each block (50-57) has a corresponding charge pump (80-87). Each charge pump (80-87) is capable of erasing a single block within the array (68). Each charge pump (80-87) has a variable capacitor (90-97). Each of the variable capacitors (90-97) can be sized according to the size of its corresponding block (50-57).