Error detection capability over CCIe protocol

• US 9,678,828 B2
• Filed: 10/09/2014
• Issued: 06/13/2017
• Est. Priority Date: 10/09/2013
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sengoku, Shoichiro
• Primary Examiner(s): NGUYEN, STEVE N
• Application Number:
  US14/511,160
• Publication Number:
  US 20150100862A1
• Time in Patent Office: 978 Days
• CPC Class Codes: G06F 11/1004 to protect a block of data words, e.g. CRC or checksum G06F11/1076 takes precedence; security arrangements for protecting computers or computer systems against unauthorized activity G06F21/00
• CPC Class Codes: G06F 13/4221 being an input/output bus, e.g. ISA bus, EISA bus, PCI bus, SCSI bus
• CPC Class Codes: H03M 13/096 Checksums

Abstract

A device is provided comprising a shared bus, a slave device, and a master device. The slave device may be coupled to the shared bus. The master device may be coupled to the control data bus and adapted to manage communications on the shared bus. Transmissions over the shared bus are a plurality of bits that are encoded into ternary numbers which are then transcoded into symbols for transmission, and either the 3 least significant bits or the least significant in the plurality of bits are used for error detection of the transmission.

Claims

1. A device comprising:

a shared bus;

a slave device coupled to the shared bus;

a master device coupled to the shared data bus and adapted to manage communications on the shared bus; and

wherein transmissions from at least one of the slave device or the master device over the shared bus are a plurality of bits that are encoded by the least one of the slave device or the master device into ternary numbers which are then transcoded into symbols for transmission, and either the 3 least significant bits or the least significant bit in the plurality of bits are used for error detection of the transmission, wherein the transcoding from ternary numbers to symbols includes obtaining a current sequential symbol based on a previous sequential symbol and a function of a current transition number, wherein the current transition number is an individual digit of a ternary number.

2. The device of claim 1, wherein the shared bus is a two-line bus and both lines of the two-line bus are used to transfer the symbols.

3. The device of claim 1, wherein a clock signal is embedded within symbol-to-symbol transitions.

4. The device of claim 3, wherein the slave device implements a state machine logic circuit that detects erroneous clock pulse misses and an erroneous extra clock pulses in the clock signal.

5. The device of claim 1, wherein the plurality of bits is a twenty-bit sequence.

6. The device of claim 5, wherein use of the 3 least significant bits for error detection guarantees detection of an error in the whole twenty-bit sequence.

7. The device of claim 6, wherein when the 3 least significant bits are used for error detection, the value of the 3 least significant bits set to a constant binary value of either “

000”

or “

111”

.

8. The device of claim 5, wherein use of the second and third least significant bits is flexibly allocated to either data transmissions or error detection.

9. The device of claim 8, wherein use of the least significant bit for error detection guarantees detection of a single-symbol error in the whole twenty-bit sequence only fifty percent of the time.

10. The device of claim 1, wherein when only the least significant bit is used for error detection, the value of the least significant bit is set to a constant binary value of either “

1”

or “

0”

.

11. A method operational on a transmitter device, comprising:

obtaining a plurality of bits to be transmitted over a shared bus, where either the 3 least significant bits or the least significant bit in the plurality of bits are used for error detection;

converting the plurality of bits into a ternary number;

converting digits of the ternary number into sequential symbols, wherein the converting of digits of the ternary number into sequential symbols includes obtaining a current sequential symbol based on a previous sequential symbol and a function of a current transition number, wherein the current transition number is an individual digit of the ternary number;

combining a plurality of symbols are into a word for transmission; and

transmitting the word over the shared bus to a receiving master or slave device.

12. The method of claim 11, further comprising:

computing a checksum for the transmitted bits; and

transmitting the checksum for the transmitted bits to the receiving master or slave device.

13. The method of claim 12, wherein the checksum is inserted within any arbitrary word for transmission to the receiving master or slave device.

14. The method of claim 11, wherein a clock is embedded within symbol-to-symbol transitions.

15. The method of claim 11, wherein the shared bus is a two-line bus and both lines of the two-line bus are used to transfer the symbols.

16. A transmitter device, comprising:

a bus interface to couple to a shared bus;

a processing circuit coupled to the bus interface and configured to;

obtain a plurality of bits to be transmitted over a shared bus, where either the 3 least significant bits or the least significant bit in the plurality of bits are used for error detection;

convert the plurality of bits are into a ternary number;

convert digits of the ternary number into sequential symbols, wherein the converting of digits of the ternary number into sequential symbols includes obtaining a current sequential symbol based on a previous sequential symbol and a function of a current transition number, wherein the current transition number is an individual digit of the ternary number;

combine a plurality of symbols into a word for transmission; and

transmit the word over the shared bus to a receiving master or slave device.

17. The device of claim 16, wherein the processing circuit is further configured to:

compute a checksum for the transmitted bits; and

transmit the checksum for the transmitted bits to the receiving master or slave device.

18. The device of claim 17, wherein the checksum is inserted within any arbitrary word for transmission to the receiving master or slave device.

19. The device of claim 16, wherein a clock is embedded within symbol-to-symbol transitions.

20. The device of claim 16, wherein the shared bus is a two-line bus and both lines of the two-line bus are used to transfer the symbols.

21. A receiver device, comprising:

a bus interface to couple to a shared bus;

a processing circuit coupled to the bus interface and configured to;

receive a plurality of symbols over the shared bus;

convert the plurality of symbols into digits, wherein the converting of the plurality of symbols into digits includes obtaining a current transition number based on a function of a current sequential symbol and a previous sequential symbol, and wherein the current transition number is an individual digit of a ternary number;

combine the digits into the ternary number;

convert the ternary number into bits, where either the 3 least significant bits or the least significant bit in the plurality of bits are used for error detection; and

ascertain an error within the received plurality of bits based on either the 3 least significant bits or the least significant bit in the plurality of bits.

22. The receiver device of claim 21, wherein a clock is embedded within symbol-to-symbol transitions of the plurality of received symbols.

23. The receiver device of claim 21, further comprising:

a state machine logic circuit that detects erroneous clock pulse misses and an erroneous extra clock pulses in the clock signal.

24. The receiver device of claim 21, wherein the shared bus is a two-line bus and both lines of the two-line bus are used to transfer the symbols.