In system calibration of wake up timer

• US 9,510,289 B1
• Filed: 11/05/2015
• Issued: 11/29/2016
• Est. Priority Date: 11/05/2015
• Status: Active Grant

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: de Ruijter, Hendricus
• Primary Examiner(s): REGO, DOMINIC E
• Application Number:
  US14/934,058
• Time in Patent Office: 390 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H03L 7/148 said digital means comprising a counter or a divider
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A wireless transceiver includes receiver front-end circuitry for processing an ingoing radio frequency (RF) signal to produce an in-going digital signal to a processor connected to receive the in-going digital signal. The processor includes sync word determination logic configured to identify a received sync word or other event or connection point and to subsequently generate an event determination signal. A low power oscillator produces low frequency pulses to a first counter. A crystal oscillator that produces higher frequency pulses to a second counter is used for the last portion of the desired sleep time for greater resolution. Thus, a calibration controller receives pulse counts from at least one of the first and second counters and determines a period between a common event of subsequent beacon signals or connection events and determines wake up times based on the received pulse counts from at least one of the first and second counters.

Claims

1. A wireless transceiver, comprising:

receiver front end wireless circuitry for processing an ingoing radio frequency (RF) signal to produce an in-going digital signal;

a processor coupled to receive the in-going digital signal, the processor including event determination logic configured to identify an event and to subsequently generate an event determination signal;

a first oscillator that generates oscillation pulses;

a first counter that counts the oscillation pulses of the first oscillator in response to the event determination signal to produce first pulse counts; and

a calibration controller that receives the first pulse counts from the first counter and the event determination signal and determines a sleep time based on the first pulse counts from the first counter in relation to subsequent event determination signals.

2. The wireless transceiver of claim 1 further comprising a second oscillator and a second counter that counts pulses of the second oscillator to produce second pulse counts.

3. The wireless transceiver of claim 2 wherein the calibration controller is configured to determine sleep times based on the first and second pulse counts from the first and second counters in relation to the subsequent event determination signals.

4. The wireless transceiver of claim 2 wherein the calibration controller is configured to activate and deactivate the second oscillator based on the first pulse counts from the first counter since the event determination signal was generated and to determine sleep times based on first and second pulse counts from the first and second counters in relation to the subsequent event determination signals.

5. The wireless transceiver of claim 2 wherein the second oscillator is a high frequency crystal oscillator.

6. The wireless transceiver of claim 1 wherein the first oscillator is a low power oscillator.

7. The wireless transceiver of claim 1 wherein the calibration controller is configured to determine wake up times based on the first pulse count in relation to a received sync word, source address, network ID and frame type.

8. The wireless transceiver of claim 1 wherein the event determination signal is generated upon determining at least one of:

a sync word;

a payload;

a preamble;

a source address;

a frame type;

a network ID;

a beacon frame; and

a connection event.

9. The wireless transceiver of claim 1 wherein the first pulse counts are produced for common portions of sequential sync words having at least one of a common source ID and a network ID.

10. The wireless transceiver of claim 1 wherein pulses are first pulse counts are produced for common portions of sequential sync words only for specified frame types.

11. The wireless transceiver of claim 1 further including a second oscillator and a second counter that produces second pulse counts wherein the first oscillator is a low power low frequency oscillator and the second oscillator is a crystal oscillator.

12. The wireless transceiver of claim 11 wherein the wireless transceiver determines the sleep time based upon a predetermined Allen deviation for an expected drift time in relation to subsequent event determination signals.

13. The wireless transceiver of claim 11 wherein the wireless transceiver counts pulses from the low power low frequency oscillator to determine sleep time.

14. The wireless transceiver of claim 11 wherein the wireless transceiver counts pulses from the crystal oscillator and the low power low frequency oscillator to determine sleep time.

15. The wireless transceiver of claim 11 wherein first and second pulse counts are produced for a same portion of sequential sync words to determine a number of first and second pulse counts that should be used to determine to the sleep time for at least one circuit that is in a low power state.

16. A method for waking up a circuit of a wireless transceiver, comprising:

receiving a wireless communication signal and detecting an event;

counting pulses generated by a first oscillator in relation to subsequent event detections;

generating a first pulse count;

waking up at least one circuit from a low power state based on a pulse count in relation to subsequent event detections; and

counting pulses generated by a second oscillator since the event was detected with a second counter and generating a second pulse count,

wherein pulses are counted between a same portion of sequential sync words to determine the first and second pulse counts of the first and second oscillators for determination of a wake up of at least one circuit that is in the low power state.

17. The method of claim 16 further including waking up at least one circuit based on the first and second pulse counts.

18. The method claim 16 wherein the second pulse count is based on the first pulse count.

19. A wireless transceiver, comprising:

receiver front end circuitry for processing an ingoing radio frequency (RF) signal to produce an in-going digital signal;

a processor coupled to receive the in-going digital signal, the processor including sync word determination logic configured to identify a received sync word and to subsequently generate an event determination signal;

a low power oscillator;

a crystal oscillator;

first and second counters configured to count oscillation pulses of the low power oscillator and the crystal oscillator in response to the event determination signal to generate first and second pulse counts, respectively;

a calibration controller that receives at least one of the first and second pulses counts from at least one of the first and second counters and determines a period between a common event of subsequent beacon signals or connection events; and

determines sleep times based on the received first and second pulse counts from at least one of the first and second counters.

20. The wireless transceiver of claim 19 wherein the transceiver is configured to:

determine a first wake up time for the crystal oscillator based on the first pulse counts; and

determine a subsequent wake up time for a circuit, device, block or element based on the second pulse counts.

21. The wireless transceiver of claim 20 wherein the second pulse counts are based on the first pulse counts.