METHOD AND APPARATUS FOR REPROGRAMMING APPLICATIONS IN EMBEDDED DEVICES

• US 20100257345A1
• Filed: 04/05/2010
• Published: 10/07/2010
• Est. Priority Date: 10/03/2007
• Status: Active Grant

• Current Assignee: Marici Holdings The Netherlands B.V.
• Original Assignee: Power-One Italy S.p.A. (ABB Limited)
• Inventors: Vernia, Filippo, Tazzari, Davide
• Granted Patent: US 8,612,734 B2
• Time in Patent Office: Days
• US Class Current: 713/1
• CPC Class Codes: G06F 8/654 using techniques specially adapted for alterable solid state memories, e.g. for EEPROM or flash memories

Abstract

A method for uploading and storing application code in a re-writable, non-volatile memory of an electronic device is carried out by means of a bootloader. The bootloader receives the application code transmitted by a master unit through a communication channel, writes at least one portion of the application code to a portion of the non-volatile memory, and validates the at least one portion of the application code by means of the bootloader.

Claims

1. A method for uploading and storing application code in a re-writable, non-volatile memory of an electronic device by means of a bootloader, comprising the steps of:

receiving the application code transmitted by a master unit through a communication channel;

writing at least one portion of the application code to a portion of the non-volatile memory;

validating the at least one portion of the application code by means of the bootloader.

2. The method of claim 1, wherein the bootloader receives in sequence a plurality of portions of the application code, each received portion is individually validated by the bootloader;

and the entire application code is validated as a whole by the bootloader.

3. The method of claim 1, further comprising the steps of:

the bootloader calculates at least a checksum or a plurality of checksums for the validation of the whole application code in its entirety, and sends the checksum(s) to the master unit;

the master unit verifies matching between the checksum(s) and corresponding checksum value(s) calculated on the application code before the transmission to the bootloader through the channel;

after having successfully completed the validation phase, the master unit sends to the bootloader at least one validation parameter for validating the application code, and the parameter is stored by the bootloader in a protected memory; and

at each startup of the device, the bootloader performs a validation of the application code through the parameter.

4. The method of claim 1, wherein each portion of the application code is constituted by a page of the application code.

5. The method of claim 1, wherein the master unit transmits each portion of application code subdivided into a series of two or more parts, sent in sequence through the channel, and re composed by means of the bootloader in order to form the portion of the application code.

6. The method of claim 5, wherein the bootloader performs a validation of each single portion of application code constituted by a series of parts singularly transmitted, before receiving the series of parts forming a subsequent portion.

7. The method of claim 1, wherein after having written a plurality of portions of the application code to the non-volatile memory, by means of the bootloader, a whole validation of the entire application code formed by the plurality of portions is carried out.

8. The method of claim 1, wherein, in order to perform the validation, the bootloader calculates a checksum of the portion of application code to be validated, and the checksum is compared with a checksum done on the same portion of code before transmission of the portion of code by the master unit.

9. The method of claim 1, wherein the bootloader calculates a checksum on at least of the portion of application code and sends the checksum to the master unit, and wherein the master unit compares the checksum calculated by the bootloader with a checksum calculated on the same portion of application code before transmission through the communication channel.

10. The method of claim 1, further comprising the steps of:

(a) receiving by the bootloader a sequence of parts of application code, the parts constituting a page of the application code;

(b) storing the parts of application code in a sequential manner;

(c) calculating the checksum of the page as all the parts of the page have been stored;

(d) storing the checksum in a register;

(e) sending the checksum to the master unit;

(f) verifying by the master unit of the checksum calculated; and

(g) repeating steps (a)-(f) for any following pages of the application code, if the verification confirmed the identity of the two checksums.

11. The method of claim 1, further comprising the steps of:

(a) receiving by the bootloader a sequence of parts of a page of the application code;

(b) storing the parts of application code in a support buffer in a sequential manner;

(c) writing the content of the support buffer to the re-writable, non-volatile memory as all the parts of the page have been stored in the support buffer;

(d) calculating the checksum of the page;

(e) storing the checksum in a register;

(f) sending the checksum to the master;

(g) verifying by the master the calculated checksum;

(h) repeating steps (a)-(f) for any following pages of the application code, if the verification confirmed the identity of the two checksums.

12. The method of claim 1, further comprising the steps of:

(a) receiving by the bootloader a page of the application code;

(b) storing the page in the re-writable, non-volatile memory;

(c) calculating the checksum of the page;

(d) storing the checksum in a register;

(e) sending the checksum to the master;

(f) verifying by the master the calculated checksum;

(g) repeating steps (a)-(f) for any following pages of the application code, if the verification confirmed the identity of the two checksums.

13. The method of claim 1, further comprising the steps of:

(a) receiving by the bootloader a sequence of parts of a page of the application code;

(b) storing the parts of application code in a support buffer in a sequential manner;

(c) calculating the checksum of the page and storing the checksum in a register, as all the parts of the page have been stored in the support buffer;

(d) writing the content of the support buffer to the rewritable non-volatile memory;

(e) sending the checksum to the master;

(f) verifying by the master the calculated checksum;

(g) repeating steps (a)-(f) for any following pages of the application code, if the verification confirmed the identity of the two checksums.

14. The method of claim 10, further comprising validating the entire application code written to the re-writable, non-volatile memory

15. The method of claim 14, wherein the bootloader calculates the checksum of the entire application code written to the re-writable, non-volatile memory and communicates the checksum to the master unit, and the master unit compares the checksum calculated by the bootloader with a checksum calculated on the application code before transmission through the communication channel to the bootloader.

16. The method of claim 1, wherein:

the application code utilizes management functions present in the bootloader and made available by the bootloader to the application code;

the bootloader is always active; and

in case of a request for update of the application code, the bootloader suspends the execution of the application until further commands and until a correct and validated application is present again.

17. The method of claim 1, wherein the bootloader is stored in a portion of protected memory.

18. An electronic device comprising:

a microcontroller;

a volatile memory unit;

a re-writable, non-volatile memory unit for storing application code;

a protected, non-volatile memory unit comprising a stored bootloader, and

the bootloader is functional to

receive the application code transmitted by a master unit through a communication channel,

write at least one portion of the application code to a portion of the non-volatile memory, and

validate the at least one portion of the application code by means of the bootloader.

19. The electronic device of claim 18 wherein the bootloader is further functional to

receive in sequence a plurality of portions of the application code,

individually validate each received portion of the application code, and

validate the entire application code as a whole.

20. The electronic device of claim 19 wherein the bootloader is further functional to perform a validation of each single portion of application code constituted by a series of parts singularly transmitted, before receiving the series of parts forming a subsequent portion.