DSI3 bus with enhanced robustness
Methods and devices provide for enhanced robustness via graceful packet error detection and packet retransmission. One illustrative sensing method includes: generating a voltage pulse on a signal conductor coupled to a sensor array including one or more active sensors, the voltage pulse representing a broadcast read command (BRC) that defines a frame of one or more time-division-multiple-access (TDMA) slots, one slot for each active sensor to send a data packet; performing current sensing on the signal conductor to receive the data packet from each of the one or more active sensors; determining whether each said data packet is received error free; and requesting retransmission of each said data packet not received error free.
1. A sensing method that comprises:
generating a voltage pulse on a signal conductor coupled to a sensor array including one or more active sensors, the voltage pulse representing a broadcast read command (BRC) that defines a frame of one or more time-division-multiple-access (TDMA) slots, one slot for each active sensor to send a data packet;
performing current sensing on the signal conductor to receive the data packet from each of the one or more active sensors;
determining whether each said data packet is received error free; and
requesting retransmission of each said data packet not received error free.
2. The method of claim 1 , wherein the signal conductor is a Distributed System Interface (DSI) signal line coupling the sensor array to an automotive electronic control unit (ECU).
3. The method of claim 1 , wherein said requesting retransmission includes, after the frame ends, generating a voltage pulse having a width indicative of the sensor or slot for which a data packet was not received error free.
4. The method of claim 1 , wherein said requesting retransmission includes, generating for each said data packet not received error free, a voltage pulse having a width indicative of the sensor or slot for which the data packet was not received error free, the voltage pulse defining one TDMA slot for retransmission of the data packet.
5. The method of claim 4 , wherein said requesting retransmission further includes:
determining whether each retransmitted data packet is received error free; and
requesting a second retransmission of each retransmitted data packet not received error free.
6. The method of claim 1 , wherein said requesting retransmission includes:
generating a voltage perturbation having a position within the frame, the position being indicative of indicative of the sensor or slot for which a data packet was not received error free; and
after the frame ends, generating a voltage pulse representing a BRC that defines a retransmission slot for the data packet not received error free.
7. The method of claim 1 , wherein said requesting retransmission includes:
generating, for each said data packet not received error free, a voltage perturbation having a position within the frame, each said position being indicative of indicative of the sensor or slot for which the data packet was not received error free; and
after the frame ends, generating a voltage pulse representing a BRC that defines a retransmission frame of one or more TDMA slots, one slot for retransmission of each data packet not received error free.
8. The method of claim 7 , wherein said requesting retransmission further includes:
determining whether each retransmitted data packet is received error free; and
requesting a second retransmission of each retransmitted data packet not received error free.
9. The method of claim 1 , wherein said requesting retransmission includes, for each said data packet not received error free, sending a command and response mode (CRM) command to the sensor for which the data packet was not received error free, the CRM command defining a slot for retransmission of the data packet.
10. A communication method in an active sensor, the method comprising:
determining a default time division multiple access (TDMA) slot for the active sensor;
detecting a voltage pulse on a signal conductor, the voltage pulse representing a broadcast read command (BRC) that defines a frame including the default TDMA slot;
sending a data packet during the default TDMA slot by modulating a current on the signal conductor;
listening for a retransmission request for the data packet; and
resending the data packet if the retransmission request is received.
11. The method of claim 10 , wherein the signal conductor is a Distributed System Interface (DSI) signal line coupling the active sensor to an automotive electronic control unit (ECU).
12. The method of claim 10 , wherein said listening for a retransmission request includes, after the frame ends, detecting a voltage pulse having a width indicative of the default TDMA slot.
13. The method of claim 12 , further comprising:
listening for a second retransmission request after said resending; and
providing a second retransmission of the data packet if the second retransmission request is received.
14. The method of claim 10 , wherein said listening for a retransmission request includes:
detecting a voltage perturbation having a position within the frame, the position being indicative of indicative of the default TDMA slot; and
after the frame ends, detecting another voltage pulse representing a BRC that defines a retransmission slot for the data packet.
15. The method of claim 14 , further comprising:
listening for a second retransmission request after said resending; and
providing a second retransmission of the data packet if the second retransmission request is received.
16. A bus master device that comprises:
a controller that generates a voltage pulse on a signal conductor coupled to a sensor array including one or more active sensors, the voltage pulse representing a broadcast read command (BRC) that defines a frame of one or more time-division-multiple-access (TDMA) slots, one slot for each active sensor to send a data packet;
a detector that performs current sensing on the signal conductor to receive the data packet from each of the one or more active sensors,
the controller determining whether each said data packet is received error free, and if not, requesting retransmission of each said data packet not received error free.
17. The bus master device of claim 16 , wherein the signal conductor is a Distributed System Interface (DSI) signal line coupling the sensor array to the bus master device.
18. The bus master device of claim 16 , wherein said requesting retransmission includes, generating for each said data packet not received error free, a voltage pulse having a width indicative of the sensor or slot for which the data packet was not received error free, the voltage pulse defining one TDMA slot for retransmission of the data packet.
19. The bus master device of claim 16 , wherein said requesting retransmission includes:
generating, for each said data packet not received error free, a voltage perturbation having a position within the frame, each said position being indicative of indicative of the sensor or slot for which the data packet was not received error free; and
after the frame ends, generating a voltage pulse representing a BRC that defines a retransmission frame of one or more TDMA slots, one slot for retransmission of each data packet not received error free.
20. A sensor device that comprises:
a controller that determines a default time division multiple access (TDMA) slot for the sensor device;
a detector that detects a voltage pulse on a signal conductor, the voltage pulse representing a broadcast read command (BRC) that defines a frame including the default TDMA slot;
a driver that sends a data packet during the default TDMA slot by modulating a current on the signal conductor,
the sensor device listening for a retransmission request for the data packet, and resending the data packet if the retransmission request is received.
21. The sensor device of claim 20 , wherein the signal conductor is a Distributed System Interface (DSI) signal line coupling the sensor device to an automotive electronic control unit (ECU).
22. The sensor device of claim 20 , wherein said listening for a retransmission request includes, after the frame ends, the detector detecting a voltage pulse having a width indicative of the default TDMA slot.
23. The sensor device of claim 20 , wherein said listening for a retransmission request includes:
the controller detecting a voltage perturbation having a position within the frame, the position being indicative of indicative of the default TDMA slot; and
after the frame ends, the detector detecting another voltage pulse representing a BRC that defines a retransmission slot for the data packet.