Transceiver for communication and method for controlling communication
An example embodiment provides a transceiver for communication includes a timing determiner that detects a fall from high level to low level of a bus signal generated by pulse width modulation of a clock signal and input from a communication bus; a transmission data signal delay adjuster that determines a second timing having a predetermined time difference from a first timing, the bus signal rising from the low level to the high level at the first timing; an encoder that extends a low level of the bus signal by changing a data signal to be output to the communication bus from high level to low level; and a timing adjustment circuit that changes the data signal to the low level at the second timing.
1. A communication circuit comprising:
a timing determination module configured to detect a change of a bus signal from a first level to a second level, the bus signal generated by modulation of a timing signal and an input from a communication bus;
a delay module configured to determine a second time having a predetermined difference value from a first time, the bus signal changing from the second level to the first level at the first time;
an encoder configured to extend the length of time the bus signal is at the second level by changing a data signal to be output to the communication bus from the first level to the second level; and
a timing adjustment module configured to change the data signal to the second level at the second time.
2. The communication circuit of claim 1 , wherein the delay module computes the predetermined difference value based on a frequency at which a harmonic level is reduced and a natural number.
3. The communication circuit of claim 1 , further comprising:
a timing signal start detection module configured to detect a start of a change of the bus signal from the second level; and
a timing signal start determination module configured to determine the first time based on a bus signal interval of the bus signal detected by the timing signal start detection module.
4. The communication circuit of claim 1 , further comprising:
a first comparator configured to compare a voltage level of the bus signal with a first reference voltage;
a second comparator configured to compare the voltage level with a second reference voltage, the second reference voltage different from the first reference voltage; and
a timing signal start determination module configured to determine a time of a start of a change of the bus signal from the second level based on a comparison of the first comparator and the second comparator.
5. The communication circuit of claim 1 , wherein the delay module determines the second time after the change of the bus signal from the first level to the second level.
6. The communication circuit of claim 5 , further comprising:
a first comparator configured to compare a voltage level of the bus signal with a first reference voltage;
a second comparator configured to compare the voltage level with a second reference voltage different from the first reference voltage; and
a timing signal start determination module configured to determine a time of a change of the bus signal from the first level to the second level based on a comparison result from the first comparator and the second comparator.
7. The communication circuit of claim 1 , wherein the delay module determines the second time to be earlier than a start of the change from the second level of the bus signal.
8. The communication circuit of claim 1 , wherein the delay module determines a time of a start of a change from the second level to the first level of the data signal to be a predetermined length of time after a timing of the change of the buss signal from the first level to the second level.
9. The communication circuit of claim 1 , wherein the transceiver is included in a node used in Clock Extension Peripheral Interface (CXPI) communication.
10. The communication circuit of claim 9 , wherein the transceiver functions as a slave node transceiver communicating with a master node transceiver over the communication bus.
11. A method for controlling communication by a transceiver over a communication bus, the method comprising:
detecting a change from a first level to a second level of a bus signal generated by modulation of a timing signal and an input from the communication bus;
determining a second time having a predetermined time difference from a first time, the bus signal changing from the second level to the first level at the first time;
extending the second level of the bus signal by changing the data signal to be output to the communication bus from the first level to the second level; and
changing the bus signal to the second level at the second time.
12. The method of claim 11 , wherein the predetermined time difference is computed based on a frequency at which a harmonic level is reduced and a natural number.
13. The method of claim 11 , further comprising:
detecting a change of the bus signal from the second level to the first level by a detector module; and
determining the first time based on a time of the change detected by the detector module.
14. The method of claim 11 , wherein:
the transceiver includes a first comparator and a second comparator; and
the method further comprises:
comparing with the first comparator a voltage level of the bus signal with a first reference voltage,
comparing the voltage level with a second reference voltage with the second comparator, the second reference voltage substantially different from the first reference voltage, and
determining a time of a change of the bus signal from the second level to the first level based on a comparison result from the first comparator and the second comparator.
15. The method of claim 11 , further comprising determining the second time to be after the change of the bus signal from the first level to the second level.
16. The method of claim 15 , wherein:
the transceiver includes a first comparator and a second comparator; and
the method further comprises:
comparing with the first comparator a voltage level of the bus signal with a first reference voltage,
comparing with the second comparator the voltage level of the bus signal with a second reference voltage, the second reference voltage substantially different from the first reference voltage, and
determining a time of a change of the bus signal from the first level to the second level based on a comparison result from the first comparator and the second comparator.
17. The method of claim 11 , further comprising determining the second time to be earlier than a time of a change of the bus signal from the second level to the first level.
18. The method of claim 11 , further comprising determining a time of a start of a change of the data signal from the second level to the first level to be a predetermined length of time after the change of the bus signal from the first level to the second level.
19. The method of claim 11 , wherein the transceiver is included in a node used in Clock Extension Peripheral Interface (CXPI) communication.
20. The method of claim 19 , wherein the transceiver functions as a slave node transceiver communicating with a master node transceiver over the communication bus.