Electronic device
AssigneeCanon Kabushiki Kaisha
InventorYousuke Hata
Life of this patent
Estimating the term…
Abstract
A communication system enabling protection at times of serial communication failure without providing a watchdog timer for each of multiple slave control units is provided in a configuration in which a master control unit and multiple slave control units are connected by serial communication. A communication system provided with multiple slave control units 102 that perform transmission and reception of serial data with a master control unit 101 for controlling serial communication and a watchdog timer 105 that simultaneously resets the multiple slave control units 102 is configured such that a watchdog signal from the master control unit 101 is input to the watchdog timer 105 via at least one of multiple serial communication lines.
Claims10
An electronic device comprising:
- a first lower layer control unit;
- a second lower layer control unit;
- an upper layer control unit configured to communicate with the first lower layer control unit through a first communication line and communicate with the second lower layer control unit through a second communication line,
- wherein the first lower layer control unit and the second lower layer control unit are controlled by the upper layer control unit;
- and
- a reset unit configured to reset the first lower layer control unit and the second lower layer control unit,
- wherein the upper layer control unit is further configured to:
- (i) monitor communication through the first communication line and communication through the second communication line for failure, (ii) transmit monitoring data, indicating that communication is being performed normally, to at least one of the first lower layer control unit and the second lower layer control unit at a predetermined time interval when a failure is not found by monitoring the first communication line and the second communication line, and (iii) stop transmission of the monitoring data when a failure is found by monitoring the first communication line and the second communication line, and
- wherein one of the first lower layer control unit and the second lower layer control unit inputs a monitoring signal to the reset unit in response to receiving the monitoring data, and
- wherein the reset unit resets the first lower layer control unit and the second lower layer control unit if a prescribed time elapses without the monitoring signal being input.
A controlling device, comprising:
- a master controller;
- a first slave controller configured to communicate with the master controller through a first communication line;
- a second slave controller configured to communicate with the master controller through a second communication line;
- and
- a reset unit configured to reset the first slave controller and the second slave controller,
- wherein the master controller comprises:
- a monitoring unit configured to monitor communications by the first slave controller and the second slave controller;
- and
- a watch dog data generator configured to generate watch dog data at a predetermined interval and transmit the generated watch dog data through the first communication line,
- wherein the watch dog data generator stops transmission of the watch dog data when a failure of communications by at least one of the first slave controller and the second slave controller is detected by the monitoring unit, and
- wherein the reset unit is configured to reset the first slave controller and the second slave controller when the watch dog data has not been transmitted from the master controller during a predetermined time period.
Dependencies are inferred from the claim text.