Oscillators – Relaxation oscillators
Patent
1998-07-10
1999-07-20
Sheikh, Ayaz R.
Oscillators
Relaxation oscillators
39575004, 395556, 331 40, 331 48, G06F 132
Patent
active
059266414
ABSTRACT:
A circuit for controlling clock frequency change circuitry to control a frequency of a system clock in response to a clock frequency indication, wherein operating circuitry of an electronic system operates responsive to the system clock. First flip-flop circuitry has an input portion coupled to receive the clock frequency indication. The first flip flop circuitry is configured to pass data from the input portion to an output portion responsive to a first polarity transition of the internal clock. Second flip-flop circuitry has an input portion coupled to the output portion of the first flip-flop circuitry. The second flip-flop circuitry configured to pass data from an input to an output portion responsive to a second polarity transition of the internal clock. A combinatorial comparator circuit is coupled to compare the output of the first flip-flop circuitry to the output of the second flip-flop circuitry and to generate, in response thereto, an equality indicator signal to indicate a result of the comparison. The equality indicator signal provides an indication to the clock frequency change circuitry that the clock frequency is to be changed.
REFERENCES:
patent: 4479096 (1984-10-01), Fowks
patent: 5056144 (1991-10-01), Cornelius
patent: 5153535 (1992-10-01), Fairbanks et al.
patent: 5189319 (1993-02-01), Fung et al.
patent: 5204953 (1993-04-01), Dixit
patent: 5254888 (1993-10-01), Lee et al.
patent: 5259006 (1993-11-01), Price et al.
patent: 5307003 (1994-04-01), Fairbanks et al.
patent: 5331669 (1994-07-01), Wang et al.
patent: 5404473 (1995-04-01), Papworth et al.
patent: 5408626 (1995-04-01), Dixit
patent: 5428790 (1995-06-01), Harper et al.
patent: 5442642 (1995-08-01), Ingalls et al.
patent: 5572719 (1996-11-01), Biesterfeldt
patent: 5606704 (1997-02-01), Pierce et al.
Serra, Micaela & Dervisoglu, Bulent I., "Testing", Chapter 79, The Electrical Engineering Handbook, Richard C. Dorf, Editor-in-Chief, pp. 1808-1837, CRC Press.
L-T Wang et al., "Feedback Shift Registers for self-Testing Circuits", VLSI Systems Design, Dec. 1986.
Masakazu Shoji, "CMOS Dynamic Gates", Chapter 5, AT&T CMOS Digital Circuit Technology, Prentice Hall, 1988, pp. 210-257.
Guthrie, Charles, "Power-On Sequencing For Liquid Crystal Displays; Why, When, and How", Sharp Application Notes, Sharp Corporation, 1994, pp. 2-1 thru 2-9.
Bernd Moeschen, "NS32SP160--Feature Communication Controller Architecture Specifications", National Semiconductor, Rev. 1.0, May 13, 1993.
Agarwal, Rakesh K., 80x86 Architecture and Programming, vol. II: Architecture Reference, Chapter 4, Prentice Hall, 1991, pp. 542-543.
Intel486 Microprocessor Family Programmer's Reference Manual, Intel Corporation, 1993.
8237A High Performance Programmable DMA Controller (8237A-4, 8237A-5), Peripheral Components, Intel, 1992, pp. 3-14 thru 3-50.
Kane, Gerry, "R2000 Processor Programming Model", Chapter 2, MIPS RISC Architecture, MIPS Computer Systems, Inc.
Hennessy, John, et al., "Interpreting Memory Addresses", Computer Architecture A Quantitative Approach, pp. 95-97, Morgan Kaufman Publishers, Inc. 1990.
Power PC601 Reference Manual, IBM, 1994, Chapter 9, "System Interface Operation", pp. 9-15 thru 9-17.
Intel Corp. Microsoft Corp., Advanced Power Management (APM) BIOS Interface Specification, Revision 1.1, Sep. 1993.
Intel Corporation, i486 Micro Processor Hardware Reference Manual, Processor Bus, pp. 3-28 thru 3-32.
Etienne Ario
National Semiconductor Corporation
Sheikh Ayaz R.
LandOfFree
Clock frequency change circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Clock frequency change circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Clock frequency change circuit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1330350