Programmable clock for an analog converter in a data processor and method therefor
First Claim
1. A method for providing a programmable clock signal to an analog converter, comprising the steps of:
- programming a high time value in a first portion of a register;
programming a low time value in a second portion of the register;
asserting the programmable clock signal;
enabling a counter to count to the high time value;
negating the programmable clock signal when the counter equals the high time value;
enabling the counter to count to the low time value;
asserting the programmable clock signal when the counter equals the low time value;
enabling the analog converter to perform a first operation when the programmable clock signal is asserted; and
enabling the analog converter to perform a second operation when the programmable clock signal is negated.
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Accused Products
Abstract
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.
5 Citations
16 Claims
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1. A method for providing a programmable clock signal to an analog converter, comprising the steps of:
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programming a high time value in a first portion of a register; programming a low time value in a second portion of the register; asserting the programmable clock signal; enabling a counter to count to the high time value; negating the programmable clock signal when the counter equals the high time value; enabling the counter to count to the low time value; asserting the programmable clock signal when the counter equals the low time value; enabling the analog converter to perform a first operation when the programmable clock signal is asserted; and enabling the analog converter to perform a second operation when the programmable clock signal is negated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A data processing system comprising:
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register means for storing a high count value and a low count value; a counter having a first input coupled to the register means for receiving one of the high count value and the low count value, the counter having a second input for receiving a system clock signal, the counter counting to provide an intermediate count value in response to the system clock signal; a detect circuit coupled to the counter for receiving the intermediate count value, the detect circuit asserting a detect signal when the count value is equal to a preselected count value; driver means coupled to the detect circuit for receiving the detect signal, the driver means selectively asserting a converter clock signal in response to the detect signal; and an analog converter coupled to the driver means for receiving the converter clock signal, the analog converter performing a conversion operation in response to the converter clock signal. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification