Initializing a ring counter

Patent metadata

Field	Value
Publication number	US-9680478-B2
Application number	US-201113242580-A
Country	US
Kind code	B2
Filing date	Sep 23, 2011
Priority date	Sep 23, 2011
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A technique includes driving a node of a stage of a ring counter to a predetermined signal state; and clocking the ring counter to cause the signal state to propagate to at least one additional stage of the ring counter to initialize the ring counter with a reset sequence.

First claim

What is claimed is:

1. A method comprising:
establishing a partial reset sequence for a ring counter, wherein the ring counter comprises a plurality of stages associated with a plurality of nodes, and establishing the partial reset sequence comprises driving a subset of nodes of the plurality of nodes to initialize the plurality of nodes to the partial reset sequence; and
clocking the ring counter to propagate the partial reset sequence to initialize the ring counter with a reset sequence.

2. The method of claim 1 , further comprising ceasing the driving of the plurality of nodes to transition the ring counter out of a reset state.

3. The method of claim 1 , wherein the driving comprises driving an output node of a stage of the plurality of stages.

4. The method of claim 1 , wherein the driving comprises activating a plurality of transistors to force the plurality of nodes to predetermined signal states in response to a reset of the ring counter.

5. An apparatus comprising:
a ring counter comprising a plurality of stages associated with a plurality of nodes; and
a controller coupled to the ring counter and adapted to drive a subset of nodes of the plurality of nodes to establish a partial reset sequence and clock the ring counter to cause the partial reset sequence to propagate to at least one other node of the plurality of nodes to initialize the ring counter with a reset sequence.

6. The apparatus of claim 5 , wherein the controller is further adapted to cease driving the subset of nodes to transition the ring counter out of a reset state.

7. The apparatus of claim 5 , wherein a node of the subset of nodes comprises an output node of a register stage of the ring counter.

8. The apparatus of claim 5 , wherein the controller comprises at least one transistor adapted to force at least one node of the subset of nodes to a predetermined signal state in response to a reset signal.

9. The apparatus of claim 5 , further comprising a buffer coupled to a node of the plurality of nodes to provide an output signal for a frequency divider.

10. An apparatus comprising:
an integrated circuit comprising a ring counter and a controller, wherein:
the ring counter comprises a plurality of stages associated with a plurality of nodes, and
the controller is adapted to drive a subset of nodes associated with the plurality of stages to initialize the plurality of nodes to a predetermined partial reset sequence and clock the ring counter to cause the partial reset sequence to propagate to at least one other node associated with the plurality of nodes to reset the ring counter.

11. The apparatus of claim 10 , wherein the controller is further adapted to transition the ring counter out of a reset state.

12. The apparatus of claim 10 , wherein at least one node of the subset of nodes comprises an output node of a stage of the plurality of stages.

13. The apparatus of claim 10 , wherein the controller comprises transistors adapted to force the subset of nodes to initiate the plurality of nodes to the predetermined partial reset sequence in response to a reset signal.

Assignees

• Karalar Tufan
• Shen David Huitse
• Silicon Lab Inc

Inventors

• Karalar Tufan
• Shen David Huitse

Classifications

• H03K23/54 Primary

  Ring counters, i.e. feedback shift register counters (H03K23/52 takes precedence) · CPC title

• H03K23/665

  by presetting · CPC title