High resolution sensing protocol
Electronic circuits and methods sense an electromagnetic property of a target, and transmit data packets that encode the property along with diagnostic messages while avoiding data loss due to truncation at high sensing speeds. Data address bits may be used to split messages across multiple data packets. Data bits may be combined into a unified header that takes less time to transmit than in prior communication protocols. The transmission duration of each data bit may be lowered, thereby increasing throughput. The receiving system may synchronize its own operation against these shortened data bits, increasing its speed. Error packets may be sent between data packets, thereby reducing time to respond to faults in safety-critical systems. And additional current levels may be used to increase the data information rate.
1. A method of transmitting packets of data that pertain to a target, the method comprising:
sensing a first signed magnitude of an electromagnetic property of the target;
transmitting a first packet of data, the first packet of data having a first header that encodes the first signed magnitude, followed by first payload pulses that encode a first portion of a message associated with the target;
sensing a second signed magnitude of the electromagnetic property of the target; and
transmitting a second packet of data, the second packet of data having a second header that encodes the second signed magnitude, followed by second payload pulses that encode a second portion of the message associated with the target.
2. The method according to claim 1 , wherein the target is associated with a magnetic field, and sensing the property of the target comprises sensing a magnitude and a direction of the magnetic field.
3. The method according to claim 2 , wherein the target comprises a wheel, and the signed magnitude of the magnetic field indicates a direction and speed of rotation of the wheel.
4. The method according to claim 1 , wherein transmitting each packet of data further comprises transmitting digital electrical pulses that encode one or more bits of configurable information, a parity bit for the second packet of data, or both.
5. The method according to claim 1 , wherein transmitting the first packet of data further comprises transmitting digital electrical pulses that encode a first message address.
6. The method according to claim 5 , wherein transmitting the second packet of data further comprises transmitting digital electrical pulses that encode the first message address, wherein the message comprises the first portion concatenated with the second portion.
7. The method according to claim 5 , wherein transmitting the second packet of data further comprises transmitting digital electrical pulses that encode a second message address, wherein the message comprises the first portion concatenated with the second portion.
8. The method according to claim 5 , wherein an encoding format of the first and second payload pulses is determined by the first message address.
9. An electronic circuit for transmitting packets of data that pertain to a target, the circuit comprising:
at least one sensing element for repeatedly sensing a signed magnitude of an electromagnetic property of the target;
an output signal generator for transmitting packets of data; and
a controller for responding, to the at least one sensing element sensing the property of the target, by causing the output generator to transmit a plurality of packets of data, each packet of data having a header that encodes a sensed, signed magnitude followed by payload pulses that encode a respective portion of a message associated with the target;
wherein the message comprises a concatenation of the respective portions.
10. The circuit according to claim 9 , wherein the target is associated with a magnetic field, and sensing the property of the target comprises sensing a magnitude and a direction of the magnetic field.
11. The circuit according to claim 10 , wherein the target comprises a wheel, and the signed magnitude of the magnetic field indicates a direction and speed of rotation of the wheel.
12. The circuit according to claim 9 , wherein each packet of data transmitted by the output signal generator further comprises digital electrical pulses that encode one or more bits of configurable information, a parity bit for the packet of data, or both.
13. The circuit according to claim 9 , wherein the controller is configured to cause the output generator to transmit, in a first one of the plurality of packets of data, digital electrical pulses that encode a first message address.
14. The circuit according to claim 13 , wherein the controller is configured to cause the output generator to transmit, in a second one of the plurality of packets of data, digital electrical pulses that encode the first message address.
15. The circuit according to claim 13 , wherein the controller is configured to cause the output generator to transmit, in a second one of the plurality of packets of data, digital electrical pulses that encode a second message address.
16. The circuit according to claim 13 , wherein the controller is configured to cause the output generator to transmit the plurality of packets of data according to an encoding format which is determined by the first message address.
17. The circuit according to claim 9 , wherein each payload pulse has a fixed duration.
18. The circuit according to claim 17 , wherein the fixed duration is at most 25 microseconds.