Electronic monitoring device having wake-up for daisy chain
A monitoring device has an event monitor, an uplink interface to a chain controller device, and a downlink interface to a further monitoring device, and a daisy controller for coupling the uplink to the chain downlink. The event monitor, in response to detecting an event in sleep mode, generates a wake-up signal. The daisy controller sets the electronic monitoring device to a wake-up request mode and disables the bidirectional data communication via the downlink interface, and subsequently transmits a wake-up request to the chain controller device via the uplink interface. In response to receiving a wake-up command, the daisy controller re-enables the bidirectional data communication via the downlink interface and sets the electronic monitoring device to the operational mode. Thereby a wake-up sequence is performed while the wake-up request mode avoids bus conflicts.
1. An electronic monitoring device, the device comprising:
an event monitor for detecting an event;
a daisy chain uplink interface for enabling bidirectional data communication to a chain controller device;
a daisy chain downlink interface for enabling bidirectional data communication to a further electronic monitoring device;
a daisy controller for coupling the daisy chain uplink interface to the daisy chain downlink interface and the event monitor;
the daisy controller being arranged to control the electronic monitoring device to be in a selected mode out of: a low-power mode, a wake-up request mode and an operational mode;
the electronic monitoring device consuming in the low-power mode less power than in the operational mode;
the event monitor being arranged to, in response to detecting the event when the electronic monitoring device is in the low-power mode, generating a wake-up signal;
the daisy controller being arranged to, in response to receiving the wake-up signal in the low-power mode, control the electronic monitoring device to be in the wake-up request mode;
the daisy controller being arranged to, when the electronic monitoring devices is in the wake-up request mode:
disable the bidirectional data communication via the downlink interface;
subsequently transmit a wake-up request to the chain controller device via the uplink interface;
re-enable the bidirectional data communication via the downlink interface, and
receive a wake-up command from the chain controller device via the uplink interface, and, in response to receiving the wake-up command, control the electronic monitoring device to be in the operational mode.
2. Electronic monitoring device as claimed in claim 1 , the daisy controller being arranged to, in response to receiving the wake-up command, perform at least one of:
re-enable the bidirectional data communication via the downlink interface;
transmit a wake-up confirmation to the chain controller device via the uplink interface.
3. Electronic monitoring device as claimed in claim 1 , the wake-up request comprises a device identifier identifying the specific electronic monitoring device in which the event was detected.
4. Electronic monitoring device as claimed in claim 2 , wherein the daisy controller is arranged to, in response to receiving a wake-up command comprising a device identifier corresponding to the specific electronic monitoring device in which the daisy controller is present, re-enabling the bidirectional data communication via the downlink interface and setting the electronic monitoring device to the operational mode.
5. Electronic monitoring device as claimed in claim 4 , the daisy controller being arranged to, in response to receiving the wake-up command, transmit a wake-up confirmation comprising the identifier to the chain controller device via the uplink interface.
6. Electronic monitoring device as claimed in claim 1 , wherein said disabling the bidirectional data communication in the wake-up request mode comprises the daisy controller discarding any wake-up request received via the downlink interface, while forwarding other messages received via the downlink interface to the uplink interface.
7. Electronic monitoring device as claimed in claim 1 , wherein said disabling the bidirectional data communication in the wake-up request mode comprises the daisy controller discarding messages received via the downlink interface, while forwarding messages received via the uplink interface to the downlink interface.
8. Electronic monitoring device as claimed in claim 1 , the event monitor being connectable to a battery, and the event being a predefined battery condition of the battery.
9. Electronic monitoring device as claimed in claim 8 , the predefined battery condition comprising at least one of
a battery voltage being below a predefined low voltage value;
a battery voltage being above a predefined high voltage value;
a battery current being below a predefined low current value;
a battery current being above a predefined high current value;
a battery temperature being above a predefined boundary value;
a battery temperature being below a predefined boundary value;
a IC die temperature of an IC die on which the electronic monitoring device is provided being above a predefined boundary value.
10. Electronic monitoring device as claimed in claim 1 , wherein the chain controller device comprises:
a daisy chain downlink interface to be coupled to the uplink interface of a first device of the electronic monitoring devices in the daisy chain for enabling bidirectional data communication, and
an interface controller connected to the daisy chain downlink interface and arranged to, in response to receiving a wake-up request from one of the multiple electronic monitoring devices via the uplink interface of the first electronic monitoring device, transmit a wake-up command to the daisy chain via the uplink interface of the first electronic monitoring device.
11. Electronic monitoring device as claimed in claim 10 , wherein the interface controller is arranged to receive a wake-up confirmation sent by the electronic monitoring devices after transmitting the wake-up command.
12. Electronic monitoring device as claimed in claim 11 , wherein the interface controller is arranged to, if the wake-up confirmation is not received within a predetermined period after transmitting the wake-up command, re-transmitting the wake-up command.
13. Electronic monitoring device as claimed in claim 11 , wherein the interface controller is arranged to in response to receiving a wake-up request comprising a device identifier of a specific electronic monitoring device, transmit a wake-up command comprising that device identifier to the daisy chain via the uplink interface of the first electronic monitoring device.
14. Electronic monitoring device as claimed in claim 11 , wherein the interface controller is arranged to:
receive a wake-up confirmation comprising the device identifier of the respective electronic monitoring device that received the wake-up command.
15. Electronic monitoring device as claimed in claim 1 , further comprising an isolating transformer having a first winding coupled to the daisy chain downlink interface and having a second winding coupled to a daisy chain uplink interface of a second electronic monitoring device.
16. Electronic monitoring device as claimed in claim 1 , wherein the device comprises an integrated circuit.
17. Electronic monitoring device as claimed in claim 10 , wherein the chain controller comprises an integrated circuit.
18. A method of controlling a daisy chain of multiple electronic monitoring devices via a daisy chain downlink interface of a chain controller device coupled to the uplink interface of a first device of the electronic monitoring devices in the daisy chain for enabling bidirectional data communication, the method comprising:
in response to detecting an event by a first electronic monitoring device:
generating a wake-up signal in the first electronic monitoring device;
controlling the first electronic monitoring device to be in a wake-up request mode;
disabling bidirectional data communication via a downlink interface of the first electronic monitoring device;
transmitting a wake-up request to the a chain controller device via an uplink interface of the first electronic monitoring device; and
re-enabling the bidirectional data communication via the downlink interface of the first electronic monitoring device; and
in response to receiving the wake-up request at the chain controller device via a downlink interface of the chain controller device, transmitting a wake-up command to the first electronic monitoring device via the downlink interface of the chain controller device; and
receiving the wake-up command in the first electronic monitoring device via the uplink interface of the first electronic monitoring device and controlling the first electronic monitoring device to be in an operational mode.