Communication including a request signal and reply signal
A controller unit is configured to transmit a request signal. A sensor is configured to transmit a reply signal in response to the request signal, the reply signal including a synchronization signal and a data signal.
1. A method comprising:
transmitting a request signal from a controller unit to a sensor, the request signal comprising at least one pulse having a pulse length;
in response to the request signal, triggering a starting of a transmission of a reply signal on the communication line from the sensor to the controller unit, the reply signal including a synchronization signal and a data signal, the data signal representing at least one nibble of data;
measuring a length of the synchronization signal received by the controller unit;
based on the measured length of the synchronization signal, determining a time base to recover data from the data signal.
2. The method according to claim 1 , wherein a sensor identification is coded into the length of the at least one pulse.
3. The method according to claim 1 , wherein a sensor range is coded into the length of the at least one pulse.
4. The method according to claim 1 , wherein a power-down is coded into the length of the at least one pulse.
5. The method according to claim 1 , wherein a self test command is coded into the length of the at least one pulse.
6. The method according to claim 1 , wherein a power-down command is coded into the length of the at least one pulse.
7. The method according to claim 1 , wherein the at least one pulse Starts with a falling edge and ends with a rising edge, and wherein the synchronization signal starts with a falling edge and ends with a rising edge, wherein the rising edge of the request signal ends before the falling edge of the synchronization signal.
8. A controller unit comprising:
a circuit to transmit a request signal over a communication line to a sensor, the request signal including at least one pulse having information coded into the pulse;
the controller configured to receive a reply signal including a synchronization signal and a data signal and to determine a time base from a length of the synchronization signal.
9. The controller unit according to claim 8 , wherein a sensor identification is coded into a length of the at least one pulse.
10. The controller unit according to claim 8 , wherein a sensor range is coded into a length of the at least one pulse.
11. The controller unit according to claim 8 , wherein a power-down is coded into a length of the at least one pulse.
12. The controller unit according to claim 8 , wherein a self test command is coded into a length of the at least one pulse.
13. The controller unit according to claim 8 , wherein a power-down command is coded into a length of the at least one pulse.
14. The controller unit according to claim 8 , wherein the controller is further configured to measure the length of the data signal and to recover data bit values based on comparing the measured length of the data signal to the time base.
15. The controller unit according to claim 14 , wherein the data signal comprises a first falling edge and a second falling edge and wherein the controller is further configured to measure the length from the first falling edge to the second falling edge.
16. The controller unit according to claim 8 , wherein the controller is further configured to determine the time base by measuring a length of the synchronization signal.
17. The controller unit according to claim 16 , wherein the synchronization signal comprises a first falling edge and a second falling edge and wherein the controller is further configured to determine the time base by measuring a length from the first falling edge to the second falling edge.