I3C high data rate (HDR) always-on image sensor 8-bit operation indicator and buffer over threshold indicator

• US 9,996,488 B2
• Filed: 08/24/2016
• Issued: 06/12/2018
• Est. Priority Date: 09/09/2013
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sengoku, Shoichiro
• Primary Examiner(s): Shyu, Jing-Yih
• Application Number:
  US15/246,098
• Publication Number:
  US 20160364353A1
• Time in Patent Office: 657 Days
• CPC Class Codes: G06F 13/1673 using buffers
• CPC Class Codes: G06F 13/24 using interrupt G06F13/32 takes precedence
• CPC Class Codes: G06F 13/362 with centralised access control
• CPC Class Codes: G06F 13/364 using independent requests or grants, e.g. using separated request and grant lines
• CPC Class Codes: G06F 13/378 using a parallel poll method
• CPC Class Codes: G06F 13/4282 on a serial bus, e.g. I2C bus, SPI bus on daisy chain buses G06F13/4247

Abstract

A method for enabling 8-bit data word access over a protocol limited to 16-bit data word access is provided. Data may be encapsulated within the lowest 19 bits of a 20-bit number. If it is ascertained that an 8-bit data word is to be used in a system supporting only 16-bit data word access, a byte-enable indicator may be provided within a most significant bit of the 20-bit number while also allocating an 8-bit data region for transfer of the 8-bit data word. The 20-bit number may then be transcoded into a 12-digit ternary number, wherein a residual numerical region is defined as a number space by which a first numerical region defined for the 12-digit ternary number exceeds a second numerical region defined by the lowest 19 bits of the 20-bit number.

Claims

1. A method, comprising:

ascertaining that a w-bit data word is to be used in a system supporting only y-bit data word access, where w and y are positive integers;

encapsulating data within the lowest n−

1 bits of an n-bit number, where n is a positive integer and n−

1 is equal to or greater than y;

providing a data word-size change indicator within a most significant bit of the n-bit number while also allocating a w-bit data region for transfer of the w-bit data word; and

transcoding the n-bit number into a k-digit odd numerical base number, where k is a positive integer and the k-digit odd numerical base number defines a first numerical region that is larger than a second numerical region defined by a n−

1-bit number space, and the n-bit number is limited to a residual numerical region defined as a number space by which the first numerical region exceeds the second numerical region.

2. The method of claim 1, further comprising:

transcoding the k-digit odd numerical base number into symbols for transmission over a bus.

3. The method of claim 1, wherein the residual numerical region accessed by setting the most significant bit of the n-bit number to one (1).

4. The method of claim 1, wherein the n-bit number is 20 bits long and the k-digit odd numerical base number is a ternary number that is 12 digits long.

5. The method of claim 1, wherein the most significant bit of the n-bit number is the 20th bit of the n-bit number and defines at least one 256 state regions.

6. The method of claim 1, wherein the most significant bit of the n-bit number is the 20th bit of the n-bit number and defines two (2) 256 state regions.

7. The method of claim 1, wherein the lowest n−

1 bits of the n-bit number includes an I3C high data rate (HDR) binary sequence.

8. The method of claim 1, further comprising:

ascertaining, prior to or concurrent with a read operation, a buffer empty condition for a transmission buffer; and

transmitting filler data if the buffer empty condition is ascertained, where such filler data is within the n-bit number.

9. The method of claim 1, further comprising:

ascertaining an over threshold condition for a transmission buffer; and

setting at least one bit of the n-bit number as an over threshold indicator to indicate the over threshold condition for the transmission buffer.

10. The method of claim 1, further comprising:

writing image data captured by an image sensor to the transmission buffer, wherein the image data is included in the lowest n−

1 bits of the n-bit number; and

sending image data from the transmission buffer to a receiving device over a control data bus according to requests from the receiving device.

11. The method of claim 1, wherein a numerical space capable of being represented by the n-bit number is larger than the first numerical region capable of being defined by the k-digit odd numerical base number.

12. The method of claim 1, wherein in a first mode of operation, the lowest n−

1 bits of the n-bit number encapsulate a first protocol, and in a second mode of operation, the n-bit number encapsulates a second protocol.

13. An image sensor device, comprising:

an image sensor to capture image data;

a transmission buffer to store the captured image data;

a communication interface to couple to a single-ended control data bus according to requests from a receiving device;

a control circuit coupled to the image sensor, the transmission buffer, and the communication interface, the control circuit configured to

ascertain that a w-bit data word is to be used in a system supporting only y-bit data word access, where w and y are positive integers;

encapsulate data within the lowest n−

1 bits of an n-bit number, where n is a positive integer and n−

1 is equal to or greater than y;

provide a data word-size change indicator within a most significant bit of the n-bit number while also allocating a w-bit data region for transfer of the w-bit data word; and

transcode the n-bit number into a k-digit odd numerical base number, where k is a positive integer and the k-digit odd numerical base number defines a first numerical region that is larger than a second numerical region defined by a n−

1-bit number space, and the n-bit number is limited to a residual numerical region defined as a number space by which the first numerical region exceeds the second numerical region.

14. The image sensor device of claim 13, wherein the n-bit number is 20 bits long and the k-digit odd numerical base number is a ternary number that is 12 digits long.

15. The image sensor device of claim 13, wherein the most significant bit of the n-bit number is the 20th bit of the n-bit number and defines at least one 256 state regions.

16. The image sensor device of claim 13, wherein the most significant bit of the n-bit number is the 20th bit of the n-bit number and defines two (2) 256 state regions.

17. The image sensor device of claim 13, wherein the control circuit is further configured to:

ascertain a buffer empty condition for the transmission buffer; and

transmit filler data if the buffer empty condition is ascertained.

18. The image sensor device of claim 13, wherein the control circuit is further configured to:

ascertain an over threshold condition for the transmission buffer; and

set at least one bit of the n-bit number as an over threshold indicator to indicate the over threshold condition for the transmission buffer.

19. The image sensor device of claim 13, wherein the control circuit is further configured to:

write image data captured by an image sensor to the transmission buffer, wherein the image data is included in the n-bit number; and

send image data from the transmission buffer to a receiving device over the control data bus according to requests from the receiving device.

20. A method for enabling 8-bit data word access over a protocol limited to 16-bit data word access, comprising:

ascertaining that an 8-bit data word is to be used in a system supporting only 16-bit data word access;

encapsulating data within the lowest 19 bits of a 20-bit number;

providing a byte-enable indicator within a most significant bit of the 20-bit number while also allocating an 8-bit data region for transfer of the 8-bit data word; and

transcoding the 20-bit number into a 12-digit ternary number, wherein a residual numerical region is defined as a number space by which a first numerical region defined for the 12-digit ternary number exceeds a second numerical region defined by the lowest 19 bits of the 20-bit number.

21. The method of claim 20, wherein the 20-bit number is limited the number space within the residual numerical region.

22. The method of claim 20, wherein the most significant bit of the 20-bit number serves to define a number space with at least two (2) 256 state regions.

23. The method of claim 20, wherein the lowest 19 bits of the 20-bit number includes an I3C high data rate (HDR) binary sequence.

24. The method of claim 20, further comprising:

ascertaining, prior to or concurrent with a read operation, a buffer empty condition for a transmission buffer; and

transmitting filler data if the buffer empty condition is ascertained, where such filler data is within the n-bit number.

25. The method of claim 20, further comprising:

ascertaining an over threshold condition for a transmission buffer; and

setting at least one bit of the 20-bit number as an over threshold indicator to indicate the over threshold condition for the transmission buffer.

26. The method of claim 20, further comprising:

writing image data captured by an image sensor to the transmission buffer, wherein the image data is included in the lowest 19 bits of the 20-bit number, and

sending image data from the transmission buffer to a receiving device over a control data bus according to requests from the receiving device.

27. An image sensor device, comprising:

an image sensor to capture image data;

a transmission buffer to store the captured image data;

a communication interface to couple to a single-ended control data bus according to requests from a receiving device;

a control circuit coupled to the image sensor, the transmission buffer, and the communication interface, the control circuit configured to

ascertain that an 8-bit data word is to be used in a system supporting only 16-bit data word access;

encapsulate data within the lowest 19 bits of a 20-bit number;

provide a byte-enable indicator within a most significant bit of the 20-bit number while also allocating an 8-bit data region for transfer of the 8-bit data word; and

transcode the 20-bit number into a 12-digit ternary number, wherein a residual numerical region is defined as a number space by which a first numerical region defined for the 12-digit ternary number exceeds a second numerical region defined by the lowest 19 bits of the 20-bit number.

28. The image sensor device of claim 27, wherein the 20-bit number is limited the number space within the residual numerical region.

29. The image sensor device of claim 27, wherein the most significant bit of the 20-bit number serves to define a number space with at least two (2) 256 state regions.

30. The image sensor device of claim 27, wherein the lowest 19 bits of the 20-bit number includes an I3C high data rate (HDR) binary sequence.