Sending a script to a virtual machine for immediate interpreting

• US 7,230,562 B1
• Filed: 08/27/2004
• Issued: 06/12/2007
• Est. Priority Date: 02/10/2004
• Status: Active Grant

• Current Assignee: IXYS Intl Limited (Littelfuse Incorporated)
• Original Assignee: ZiLOG Incorporated (Littelfuse Incorporated)
• Inventors: Provis, Adam P. G., Miramontes, Oscar C., Vergis, George C.
• Primary Examiner(s): Holloway, III, Edwin C.
• Application Number:
  US10/928,502
• Time in Patent Office: 1,019 Days
• Field of Search: 341/173, 341/176, 340/825.22, 340/825.24, 340/825.25, 340/825.69, 340/825.72, 348/734, 398106-112, 717/115, 717/139
• US Class Current: 341/176
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: G08C 2201/33 Remote control using macros, scripts
• CPC Class Codes: G08C 2201/50 Receiving or transmitting feedback, e.g. replies, status updates, acknowledgements, from the controlled devices
• CPC Class Codes: G08C 23/04 using light waves, e.g. infrared
• CPC Class Codes: H04L 1/1803 Stop-and-wait protocols
• CPC Class Codes: H04N 21/41265 having a remote control device for bidirectional communication between the remote control device and client device unidirectional remote control device H04N21/42204
• CPC Class Codes: H04N 21/42221 Transmission circuitry, e.g. infrared [IR] or radio frequency [RF]
• CPC Class Codes: H04N 21/42226 Reprogrammable remote control devices
• CPC Class Codes: H04N 21/4437 Implementing a Virtual Machine [VM] virtual machines in general G06F9/45533

Abstract

A security channel is provided for communication with an eight-bit, register-based, virtual machine. The virtual machine is placed into a direct mode, and then individual script instructions are sent to the virtual machine across the security channel for immediate interpreting by the virtual machine. The instructions are interpreted one by one as they are received. This feature can be used in debugging. This feature is usable in applications in which resident code is not required, but rather incoming script instructions are adequate to control device operation. A large memory is not required to store scripts, thereby reducing virtual machine system cost. Script instructions usable in the direct mode include instructions for loading a script API or machine code API onto the virtual machine from an external system, for loading a script, and for causing the virtual machine to output the contents of memory and/or internal registers to the external system.

Claims

1. An apparatus comprising:

a processor;

a memory storing a script interpreter and a script, the script interpreter executing on the processor, the script being interpreted by the script interpreter; and

an execute script direct functionality, wherein a script instruction is received onto the apparatus when the script is being interpreted, the execute script direct functionality causing the script instruction to be interpreted by the script interpreter.

2. The apparatus of claim 1, wherein the script interpreter and the processor together comprise an eight-bit virtual machine, and wherein no operating system is executing on the processor.

3. The apparatus of claim 2, wherein the execute script direct functionality is an application programming interface (API) that is also part of the virtual machine.

4. The apparatus of claim 3, wherein the execute script direct functionality is an amount of machine code that is stored in the memory and that is executed by the processor.

5. The apparatus of claim 1, wherein interpretation of the script automatically continues after the script instruction is interpreted.

6. The apparatus of claim 1, wherein the apparatus is a microcontroller.

7. The apparatus of claim 1, wherein the script instruction is received onto the apparatus via a secure communication link.

8. The apparatus of claim 1, wherein the script instruction is received onto the apparatus via a bidirectional communication link, wherein the script instruction includes a direct script instruction, interpretation of the direct script instruction causing the apparatus to output a communication over the bidirectional communication link such that the apparatus then listens for a authentication communication to be received back onto the apparatus via the bidirectional link, wherein the script instruction is only interpreted if the authentication communication is received.

9. The apparatus of claim 1, wherein the apparatus is a microcontroller, the microcontroller being able to communicate with an external device via a bidirectional communication link, and wherein interpretation of the script instruction causes contents of a portion of the memory to be output from the apparatus across the bidirectional communication link.

10. The apparatus of claim 1, wherein the apparatus is a microcontroller, the microcontroller being able to communicate with an external device via a bidirectional communication link, the microcontroller including a plurality of registers, and wherein interpretation of the script instruction causes contents of at least one of the plurality of registers to be output from the apparatus across the bidirectional communication link.

11. The apparatus of claim 1, wherein the apparatus is a microcontroller, the microcontroller being able to communicate with an external device via a bidirectional communication link, the script having an identifier, and wherein interpretation of the script instruction causes the identifier to be output from the apparatus across the bidirectional communication link.

12. The apparatus of claim 1, wherein the apparatus is a microcontroller, the microcontroller being able to communicate with an external device via a bidirectional communication link, a location in the script being pointed to by a script instruction pointer, and wherein interpretation of the script instruction causes the script instruction pointer to be output from the apparatus across the bidirectional communication link.

13. The apparatus of claim 1, wherein the apparatus is a remote control device, and wherein interpretation of the script causes an operational signal to be transmitted from the remote control device.

14. The apparatus of claim 1, wherein the apparatus is a motor control apparatus, and wherein interpretation of the script causes the apparatus to control a motor.

25. The apparatus of claim 4, wherein the amount of memory code is no more than approximately 0.5 kilobytes.

26. The apparatus of claim 8, wherein the communication comprises an encrypted number and a pseudorandom number, wherein the authentication communication comprises a decrypted number, wherein the decrypted number is a decrypted version of the encrypted number based in part on the pseudorandom number.

27. The apparatus of claim 26, wherein in response to the decrypted number being acceptable to the apparatus, the apparatus permits an external device to transmit at least one other script instruction for interpretation by the script interpreter.

28. The apparatus of claim 27, wherein after at least one other script instruction is interpreted, the apparatus initiates transmission of a response signal to the external device.

29. The apparatus of claim 26, wherein the apparatus receives another script instruction via the bidirectional communication link, wherein the another script instruction includes a restart script instruction, interpretation of the restart script instruction causing the apparatus to discontinue executing at least one script instruction from the external device.

15. An apparatus comprising:

an eight-bit processor that executes a script interpreter, wherein the eight-bit processor executes no operating system; and

means for receiving a script instruction from a source external to the apparatus and for causing the script instruction to be interpreted by the script interpreter.

16. The apparatus of claim 15, wherein the means comprises:

a bidirectional communication link over which the script instruction is received onto the apparatus, the script interpreter interpreting a script when the script instruction is received onto the apparatus; and

an execute script direct functionality that causes interpreting of the script to be halted such that the script instruction is interpreted by the script interpreter.

17. The apparatus of claim 15, wherein the apparatus is a microcontroller, and wherein the microcontroller has no more than 64 k of program memory.

18. A method, comprising:

(a) executing a script interpreter on an eight-bit microcontroller, wherein the eight-bit microcontroller executes no operating system;

(b) receiving a script instruction onto the eight-bit microcontroller; and

(c) in response to said receiving causing the script instruction to be interpreted.

19. The method of claim 18, wherein the microcontroller and the script interpreter together comprise an eight-bit virtual machine.

20. The method of claim 18, wherein the script instruction is received onto the microcontroller via a secure communication link.

21. The method of claim 18, wherein the script instruction is received from an external source, the method further comprising:

authenticating the external source prior to allowing the script instruction to be interpreted in (c).

22. The method of claim 18, wherein there is no script being interpreted by the script interpreter when the script instruction is received on the microcontroller in (b).

23. The method of claim 18, wherein there is no script stored on the microcontroller in (a).

24. The method of claim 18, wherein there is a script being interpreted by the script interpreter when the script instruction is received on the microcontroller in (b), interpretation of the script being suspended so that the script instruction can be interpreted in (c).

30. A method of debugging a portable device, the method comprising:

(a) executing a script interpreter on a microcontroller, wherein the microcontroller executes no operating system;

(b) receiving a script instruction onto the microcontroller; and

(c) in response to said receiving, causing the script instruction to be interpreted regardless of whether the script interpreter interprets any script.

31. The method of claim 30, further comprising:

in response to executing the script instruction, initiating transmission of an encrypted number with a pseudorandom number to an external system; and

receiving a decrypted number, wherein the decrypted number is a decrypted version of the encrypted number based in part on the pseudorandom number.

32. The method of claim 31, further comprising:

validating the received decrypted number; and

accepting at least one other script instruction from the external system for immediate interpretation in response to the decrypted number being valid.

33. The method of claim 32, further comprising:

receiving another script instruction via a communication link, wherein the another script instruction includes a restart script instruction; and

not permitting interpretation of at least one script instruction from the external system in response to interpretation of the restart script instruction.

34. The method of claim 30, wherein the script instruction initiates transmission of contents of memory to the external system.