Communication system, master device, slave device, and control method for communication system

A master device comprising:

• a first counter that increments a first count value every time a first unit time elapses;
• a second counter that updates a second count value every time a second unit time elapses;
• and
• a master transmitter that transmits timing information indicating a timing at which the second count value is updated to at least one slave device that communicates with the master device.

A slave device that communicates with a master device, wherein

• the master device includes a first counter that increments a first count value every time a first unit time elapses, a second counter that updates a second count value every time a second unit time elapses, and a master transmitter that transmits timing information indicating a timing at which the second count value is updated to the slave device, and
• the slave device comprises:
• a third counter that increments a third count value every time the first unit time elapses;
• a fourth counter that increments a fourth count value every time a third unit time shorter than the first unit time elapses, and resets the fourth count value at a timing at which the third counter increments the third count value;
• and
• a slave receiver that receives the timing information transmitted from the master transmitter.

A control method for a communication system including a master device, and at least one slave device that communicates with the master device, the method comprising:

• by the master device,
• incrementing a first count value every time a first unit time elapses;
• updating a second count value every time a second unit time elapses;
• and
• transmitting timing information indicating a timing at which the second count value is updated to the at least one slave device, and
• by the at least one slave device,
• incrementing a third count value every time the first unit time elapses;
• incrementing a fourth count value every time a third unit time shorter than the first unit time elapses, and resetting the fourth count value at a timing of incrementing the third count value;
• and
• receiving the timing information transmitted from the master device.