US 7,003,309 B2 · Master-slave communication system and electronic apparatus utilizing such system

Abstract

A communication system has a master device and a slave device clocked by the system clock generated by the master device for data transfer between them. When no data transfer takes place between them for a predetermined period, the slave device goes into a sleep mode. The slave device in the sleep mode can return to the active mode when it receives a system clock. Thus, the slave device can be placed in the sleep mode and return to the active mode without any additional signal lines. The communication system can save a large amount of power during the sleep.

Drawings

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Drawings

Claims8

Dependent claims

A communication system, comprising:

a master device generating a system clock;
and
at least one slave device connected with said master device by a clock line and at least one data line, wherein
said slave device and said master device are adapted to serially exchange data in synchronism with said system clock;
said slave devices goes into a sleep mode when zero communication status lasts a predetermined period;
and
upon receipt of at least one system clock, said slave device in said sleep mode returns to the active state, wherein
said slave device has a serial interface (I/F), a host controller, and an internal clock;
said internal clock is provided to said host controller but not to said serial I/F in said sleep mode;
wherein duration of said zero communication status is determined by a timer provided in said slave device.

7 more elements

Dependencies are inferred from the claim text.

Description4,601 words

Summary1,047 words

#The invention relates to a master-slave communication system for use in serial data transfer between a master device and a slave device, and to electronic apparatus utilizing such a system.

#In conventional master-slave systems transferring data, a limited number of data transfer lines including a clock line, data lines, and chip selection lines are established between them to transfer synchronized serial data. Such conventional master-slave communication systems are widely used for inter-chip communication in many electronic apparatuses including cellular phones.

#In this type of conventional communication system, slave devices must be held active at all time in order to wait for incoming signals. Therefore, the slave devices cannot be inactivated (sleep mode) even when they do not receive any data for a long time.

Brief description of the drawings6 figures

#The invention will now be described by way of example with reference to the accompanying drawings, in which:

#FIG. 1 is a block diagram of a first communication system according to the invention;

#FIG. 2 is a timing diagram of the slave device shown in FIG. 1 returning from a sleep mode to an active mode;

Detailed description3,429 words

#Referring now to FIG. 1, there is shown a first embodiment of a master-slave communication system according to the invention. FIG. 2 shows a timing diagram of the communication system of FIG. 1, with the slave device in a sleep mode returning to an active mode. Flowcharts of FIGS. 3(a) and (b) depict the operations of the communication system carried out by the master device (FIG. 3(a)) and the slave device (FIG. 3(b)).

#As shown in FIG. 1, a first communication system 100 has a slave device 10 and a master device 50, which are connected by a system clock line S1, an up data line S2, and a down data line S3. A chip select signal line (not shown) may be also connected to the chip as needed.

#System clock CLK is generated by the master device 50 and supplied onto the system clock line S1. The master device 50 may be formed of a general purpose one-chip microcomputer. The up data line S2 transmits data TX issued by the slave device 10 to the master device 50. The down data line S3 transmits data RX issued by the master device 50 to the slave device 10. These data are transferred in synchronism with the system clock CLK.

Facts

Application

10/154,696Filed 23 May 2002

Priority

JP 2001-15987129 May 2001

Published

US 2002/0183092 A15 Dec 2002

Granted

21 Feb 2006

Term ended

30 Jun 2023

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 403 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification5 codes

G06F 13/385
Using universal interface adapter: for adaptation of a particular data processing system to different peripheral devices
G06F 13/4291
On a serial bus, e.g. I2C bus, SPI bus: using a clocked protocol
Y02D 10/00
Energy efficient computing
G06F
Computing and data processing

Timeline

29 May 2001Priority claimedJP 2001-159871
23 May 2002Application filedUS 10/154,696
23 May 2002Assigned to Rohm Co., Ltd.assignment of assignor's interest
5 Dec 2002PublishedUS 2002/0183092 A1
21 Feb 2006GrantedUS 7,003,309 B2
30 Jun 2023Term endedEstimated, includes 403 days of adjustment

Master-slave communication system and electronic apparatus utilizing such system

Life of this patent

Master-slave communication system and electronic apparatus utilizing such system

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims8

Description4,601 words

Drawings

Classification5 codes

Life of this patent

Description4,601 words