SERIAL DATA COMMUNICATION SYSTEM AND METHOD

• US 20090010371A1
• Filed: 12/14/2006
• Published: 01/08/2009
• Est. Priority Date: 01/03/2006
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Breitfuss, Klemens
• Granted Patent: US 8,284,823 B2
• Time in Patent Office: Days
• US Class Current: 375/362
• CPC Class Codes: G06F 1/08 Clock generators with changeable or programmable clock frequency
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/324 by lowering clock frequency
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: G06F 13/4291 using a clocked protocol
• CPC Class Codes: H04L 7/0008 Synchronisation information channels, e.g. clock distribution lines
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A serial data communication system (10) comprises—a local clock generation device (12) adapted for generating a clock signal (16) with a duty cycle depending on a control signal (18), and—a serial data communication control device (14) adapted for generating the control signal (18) depending on the receipt of a serial data signal and for deriving a transmit and receive clock signal (20, 21) from the clock signal (16) received from the local clock generation device (12).

Claims

1. A serial data communication system comprising

a local clock generation device adapted for generating a clock signal with a duty cycle depending on a control signal, and

a serial data communication control device adapted for generating the control signal depending on the receipt of a serial data signal and for deriving a transmit and receive clock signal from the clock signal received from the local clock generation device.

2. The system of claim 1, wherein the local clock generation device is adapted to generate the clock signal with a predefined clock having a first duty cycle if the control signal comprises a first state and having a second duty cycle differing from the first duty cycle if the control signal comprises a second state.

3. The system of claim 1, wherein the serial data communication control device is adapted to derive the transmit and receive clock signal from the clock signal received from the local clock generation device after the serial data signal was received for a predefined time.

4. The system of claim 1, wherein the serial data communication control device is adapted to generate a pulse of the receive clock signal triggered by the negative edge of a pulse of the clock signal when the control signal comprises a respective state.

5. The system according to claim 1, wherein it is adapted to transmit and receive data serially according to the RS232 standard.

6. A local clock generation device comprising

an oscillator for generating a local high frequency clock signal, and

a clock generation circuit adapted for generating a clock signal from the local high frequency clock signal with a duty cycle depending on a control signal.

7. A serial data communication control device comprising

a transmit and receive clock generation circuit adapted to generate a control signal from a receive data signal for controlling the generation of a clock signal, and

data processing circuitry for processing data received from a serial data communication device and data to be transmitted to a serial data communication device.

8. The device of claim 7, wherein the transmit and receive clock generation circuit comprises a control signal generation circuit with a multiplexer, which receives a receive data signal and a constant signal on its input side, and a multiplexer control circuitry comprising a counter and being adapted for switching either of the input signals of the multiplexer to the multiplexer output as the control signal depending on the count of the counter.

9. A serial data communication method wherein

a local clock generation device generates a clock signal with a duty cycle depending on a control signal, and

a serial data communication control device generates the control signal depending on the receipt of a serial data signal and derives a transmit and receive clock signal from the clock signal received from the local clock generation device.