Motorola Corporation

Colleen M Collins

Jules D Campbell, Jr

Kelvin E McCollough

Anthony M Reipold

Mark R Heene

William D Huston

Kenneth L McIntyre, Jr

Cheri L Harrington

Carl D Wiseman

Robert L Winter

A data processing system (20) having programmable chip select signal negation. A user programmable 'NEGATE EARLY' value generates a chip select negation one bus cycle before the end of a transaction, giving an external device additional time to disconnect from the current bus cycle before the start of the next bus cycle. Early negation of a chip select signal provides an efficient method of interface with slower devices while providing adding functionality to the chip select signal.

Method and apparatus for programmable chip select negation in a data

A data processing system (10) includes a programmable clock signal for an analog converter (28). A duty cycle of the programmable clock signal is programmed by an external user in a prescaler rate selection register (16). A counter subsequently counts for a first period of time corresponding to a phase in which the programmable clock signal is asserted. The counter then counts for a second period of time corresponding to a phase in which the programmable clock signal is negated. By allowing the user to program and modify the duty cycle of the programmable clock signal, the performance of the analog converter (28) may be optimized without constraining the requirements of an external system clock.

Programmable clock for an analog converter in a data processor and

An analog-to-digital conversion module, QADC (1), and method minimize software involvement by providing a pause capacility. Each queue in the QADC (1) has one or more Conversion Command Words, CCWs (82), in a Conversion Command Word Table (62). Each conversion command word, CCW (82), has a Pause bit which can be used to create multiple sub-queues of A/D conversions without requiring the use of interrupts. The Pause bit can be used to place a queue in a pause state. When a queue enters a pause state, the scanning of CCWs (82) is stopped. The queue must then receive a trigger in order for the scanning of CCWs (82) to continue again.

Automatic A/D converter operation with pause capability

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Austin, TX, United States of America

Colleen M Collins