JP2008102761A - Method for updating embedded firmware - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a firmware updating method for writing an updating program module and its address in a RAM requires updating firmware existence confirmation processing on the head of each firmware module and a firmware updating method for copying the whole contents of a ROM in a RAM requires a ROM replacement detection means and the method can not be applied to an LSI into which a ROM, a RAM and a CPU is integrated. <P>SOLUTION: An information processing apparatus is provided with a ROM for storing the information of firmware or the like, a RAM to which the ROM information is copied, a CPU for executing the firmware, and a communication means for communicating with the external. In a function call during the firmware execution of the CPU, corrected or added firmware is written in the RAM through the communication means as the firmware change or firmware addition of the ROM on the basis of the function address information of the RAM which is copied from the ROM at the time of start and the address of an applicable function of the RAM is rewritten by a newly written RAM address. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a firmware update technique for solving a malfunction of firmware or changing / adding a function in an embedded information processing apparatus.

  Embedded information processing devices include mask ROM (Read Only Memory) that stores firmware and fixed data, RAM (Random Access Memory) that stores variables that are referenced during program execution, data processing and peripherals based on firmware Generally, a CPU (Central Processor Unit) that controls functions is provided. When a malfunction occurs in the firmware, the function is changed, or a new addition is made in this embedded information processing apparatus, it is necessary to update the firmware (program) stored in the mask ROM. As a method of updating the program, a method of physically replacing the built-in information processing apparatus itself with an information processing apparatus that has updated the program can be considered. However, the built-in information processing apparatus is generally an LSI (Large Scale Integrated circuit), and is not usually performed because it requires a great deal of cost and labor. In particular, an embedded LSI mounted on a mobile phone or the like is unrealistic because an enormous number of LSIs are produced.

  As a firmware update method for solving the above problem, a program module to be updated in a free area or a specific area of RAM and address information of the RAM in which the program module is written are written, and the update program module written in the RAM executes As described in Japanese Patent Application Laid-Open No. 5-73292 (Patent Document 1) and Japanese Patent Application Laid-Open No. 6-44078 (Patent Document 2), for example, a method for solving the problem and adding a function is described. It has been proposed in the past.

JP-A-5-73292 JP-A-6-44078

However, the one described in Japanese Patent Application Laid-Open No. 5-73292 of Patent Document 1 is configured to check whether the modified firmware is arranged in the RAM when each module of the firmware is executed. There is a problem that it is necessary to incorporate in advance a process for checking whether or not there is updated firmware at the head of each firmware module.
Further, the one described in Japanese Patent Laid-Open No. 6-44078 of Patent Document 2 is executed after copying the entire contents of the mask ROM onto the RAM, and detects that the mask ROM has been replaced and stores it in the RAM. Since it is configured to write an updated program module, it requires special hardware to detect mask ROM replacement, and cannot be applied to an LSI in which mask ROM, RAM, and CPU are integrated. .

  The present invention has been made to solve the above-described problems, and does not require special firmware or hardware for updating the firmware, and updates the firmware written in the mask ROM with a simple configuration. It is an object of the present invention to obtain an embedded firmware update method capable of adding a new firmware function.

An embedded firmware update method according to the present invention includes:
Executes firmware, mask ROM that stores the address information of all functions other than the main data and fixed data referenced by the firmware and firmware, RAM that copies the address information of the functions stored in the mask ROM, and mask ROM firmware CPU (Central Processor Unit) and communication means for communicating with the outside,
The function address information stored in the mask ROM is copied to the RAM at startup, and the function call when the CPU executes the mask ROM firmware is operated based on the function address information copied to the RAM. In a built-in information processing apparatus having a function for writing data input from a communication means to an arbitrary address on a RAM.
When changing the firmware of the mask ROM or adding the firmware, the modified firmware from the outside or the firmware to be added is written to the RAM via the communication means and the address information of the corresponding function copied to the RAM is corrected. Alternatively, the firmware to be added is rewritten to the RAM address information newly written.

  The embedded firmware update method according to the present invention copies the function address table located on the mask ROM to the RAM when the embedded information processing apparatus in which the method is used is activated, and updates the function in the firmware. When a firmware function is added, the updated firmware or additional firmware is written into the RAM, the contents of the function address table copied to the RAM are rewritten, and writing to the RAM is performed via communication means. Therefore, there is no need for special firmware or hardware to update the firmware, and it is possible to update the firmware written in the mask ROM or add new firmware functions with a simple configuration. How to update There is an effect that can be obtained.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing the configuration of an embedded information processing apparatus to which a firmware update method according to Embodiment 1 of the present invention is applied. Generally, such an embedded information processing apparatus is configured as an LSI.
In FIG. 1, 1 is a CPU, 2 is a mask ROM, 3 is a RAM, 4 is a communication means for communicating data with an externally connected host controller or the like.
The communication means 4 is provided to realize a command interface between an external host controller and the embedded information processing apparatus, and the embedded information processing apparatus is based on a command input via the communication means 4. Various processes.
The mask ROM 2 has three areas, the firmware main body is stored in 2a, and the function address table in which the address information on the mask ROM of all functions other than the main processing of the firmware is tabulated is stored in 2b. 2c stores fixed data such as initial values of variables.
The RAM 3 is also divided into three areas. There are a data area 3a for storing variables and the like during execution of firmware, a function address table copy area 3b for storing a copy of the function address table, and an unused area 3c in an unused state. To do.

  The built-in information processing apparatus configured as described above copies the function address table stored in the area 2b of the mask ROM 2 to the function address table copy area 3b of the RAM 3 at the time of startup after power-on. In general, this process may be implemented in a firmware startup process that is always executed after reset release. When each function is called from the main process, the CPU 1 refers to the address information of the function stored in the function address table copy area 3b of the RAM 3 and executes the function itself. Such an operation can be realized by a general CPU without providing special means if the firmware is mounted so as to indirectly address each function.

Next, as an example, a method for updating the function A in the built-in information processing apparatus according to the first embodiment of the present invention will be described with reference to FIG.
First, the user creates a function A ′ by updating the processing contents of the function A. prepare.
Next, the user determines in which area of the free area 3 c of the RAM 3 the function A ′ is to be written.
Next, the host controller writes the function A ′ into the determined free space 3 c of the RAM 3 via the communication means 4.
The function A ′ writes the address value of the function A stored in the function address table copy area 3b through the communication means 4, that is, the address value of the original function A stored in the mask ROM. Rewritten to the address value on the read RAM.
The operation of writing to an arbitrary address on the RAM via the communication means 4 is easy if a command for specifying the write address, the data to be written, the number of data to be written, etc. is provided and the processing corresponding to the command is implemented in the firmware. It is possible to realize.

By doing so, the next time function A is called from the main routine, function A ′ is executed instead of function A.
The timing for executing the writing of the updated firmware code to the RAM 3 and the change of the function address table copy area 3b from the host controller may be immediately after the communication means 4 becomes effective after the activation or the function of the function to be updated. Immediately before use, the embedded information processing apparatus itself need not be involved.

The method for changing the processing contents of the function has been described above, but it is also possible to add a function to the firmware. As an example, a method for adding new firmware processing before and after the function A will be described with reference to FIG.
First, the user creates a function C including newly added firmware processing and function A call processing. Newly added firmware processing may be incorporated as pre-processing of the function A or post-processing.
Next, the user determines in which area of the free area 3 c of the RAM 3 the function C is to be written.
Next, the host controller writes the function C into the free area 3 c of the RAM 3 via the communication unit 4.
The function C is written by the host controller via the communication means 4 with the address value of the function A stored in the function address table copy area 3b, that is, the original address value of the function A stored on the mask ROM. Rewrite to address value on RAM.
By doing so, the newly added function and the function A are executed by executing the function C at the next timing when the function A is called from the main routine.

  As described above, the firmware update method in the embedded information processing apparatus according to the first embodiment copies the function address table arranged on the mask ROM at startup to update the function in the firmware. When a firmware function is added, the updated firmware or additional firmware is written into the RAM and the contents of the function address table copied to the RAM are rewritten. Since writing to the RAM is performed from the host controller via a communication means provided as a command interface with the host controller, special firmware and hardware for updating the firmware are required. In addition, there is an effect that it is possible to obtain an embedded firmware update method capable of updating the firmware written in the mask ROM or adding a new firmware function with a simple configuration.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing the configuration of an embedded information processing apparatus to which the firmware updating method according to the second embodiment of the present invention is applied. The same means as those of the first embodiment are indicated by the same numbers, and the description thereof is omitted. In FIG. 4, 5 is a NVRAM (Non Voltage RAM), and 6 is a RAM.
NVRAM 5 is a battery-backed RAM to which a dedicated power supply system different from other components is assigned. It can hold written data if the dedicated power is turned on, so it can hold data with low power consumption. It is often used when you want to. The NVRAM 5 is divided into three areas: a data area 5a for storing variables and the like at the time of firmware execution, a function address table copy area 5b for storing a copy of the function address table, and a free area 5c in an unused state.
In the second embodiment, the RAM 6 is used only as a data area.

  The built-in information processing apparatus of the second embodiment configured as described above copies the function address table stored in the area 2b of the mask ROM 2 at the time of startup after the first power-on to the function address table of the NVRAM 5. Copy to area 5b. When each function is called from the main process, the CPU 1 executes the function by referring to the address information of the function stored in the function address table copy area 5b of the NVRAM 5.

Next, as an example, a method for updating function A in the embedded information processing apparatus according to Embodiment 2 of the present invention will be described with reference to FIG.
First, the user creates a function A ′ in which the processing content of the function A is updated. Next, the user determines in which area of the empty area 5 c of the NVRAM 5 the function A ′ is to be written. Next, the function A ′ is written by the host controller to the empty area 5c of the NVRAM 5 via the communication means 4, and the address value on the mask ROM of the original function A stored in the function address table copy area 5b is changed to the function A Rewrite to the address value on NVRAM where 'is written. This operation is performed immediately after the first activation. By doing so, the next time function A is called from the main routine, function A ′ is executed instead of function A.

Next, a case where a new firmware process is added before and after the function A will be described as an example of a method for adding a function to firmware.
First, the user creates a function C including newly added firmware processing and function A call processing. Newly added firmware processing may be incorporated as pre-processing of the function A or post-processing.
Next, the user determines in which area of the empty area 5 c of the NVRAM 5 the function C is to be written.
Next, the host controller writes the function C into the empty area 5 c of the NVRAM 5 through the communication means 4.
The function C is written by the host controller through the communication means 4 with the address value of the function A stored in the function address table copy area 5b, that is, the original address value of the function A stored in the mask ROM. Rewrite to address value on NVRAM5.
By doing so, the function C is executed at the next timing when the function A is called from the main routine, and the newly added function and the function A are executed.

  When the embedded information processing apparatus is started next time, the data in the NVRAM 5 is checked. If the data is retained, the updated firmware code is not written into the NVRAM 5 and the function address table copy area 5b is not changed. . The data in the NVRAM 5 may be checked by reading the data in the NVRAM 5 from the host controller via a command, or a method of checking the data in the startup of the firmware of the embedded information processing apparatus.

  As described above, the firmware update method in the embedded information processing apparatus according to the second embodiment copies the function address table placed on the mask ROM to NVRAM at the time of startup, and updates the function in the firmware. When a firmware function is added, the updated firmware or additional firmware is written in the NVRAM and the contents of the function address table copied to the NVRAM are rewritten. Since writing to the NVRAM is performed from the host controller via a communication means provided as a command interface with the host controller, no special firmware or hardware for updating the firmware is necessary. The effect that it is possible to update the firmware written in the mask ROM or add a new firmware function with a simple configuration, and to obtain a method for updating the embedded firmware with a short startup time There is.

Embodiment 3 FIG.
For example, in an embedded information processing device mounted on a camera module or the like, parameters are often adjusted before product shipment in order to absorb variations in performance of each individual camera module. Need to run the firmware module. Since such a firmware module is not used after the product is shipped, if it is arranged in the mask ROM area, the mask ROM area is compressed.
Therefore, at the time of parameter adjustment before product shipment, the firmware module for adjustment is arranged in the RAM or NVRAM and executed according to the procedure described in the first or second embodiment, and the firmware is updated or updated after the product is shipped. If the procedure described in the first or second embodiment is executed in the RAM or NVRAM used before shipment from the factory, the above problem can be solved and the mask ROM area can be added. It can be used effectively.

  As described above, in the firmware updating method in the embedded information processing apparatus according to the third embodiment, the firmware dedicated to parameter adjustment is written in a free area of the RAM or NVRAM before shipment from the factory, and the updated firmware or Since the additional firmware is written to the RAM or NVRAM used before shipment from the factory, the mask ROM area is required after the product is shipped in addition to the effects shown in the first and second embodiments. There is an effect that only the correct firmware can be arranged.

  The firmware update method according to the present invention is applied to, for example, a signal processing LSI for a built-in mobile camera such as a mobile terminal or a mobile phone, and can update the firmware when a malfunction occurs or a function is changed or added.

1 is a block diagram showing a configuration of an embedded information processing apparatus to which a firmware updating method according to Embodiment 1 of the present invention is applied. FIG. 3 is an explanatory diagram of a function A update method in the built-in information processing apparatus according to Embodiment 1. FIG. 3 is an explanatory diagram of a method for adding new firmware processing in the embedded information processing apparatus of Embodiment 1. FIG. It is a block diagram which shows the structure of the embedded information processing apparatus with which the firmware update method by Embodiment 2 of this invention is applied. FIG. 10 is an explanatory diagram of a function A update method in the embedded information processing apparatus of the second embodiment.

Explanation of symbols

  1; CPU, 2; mask ROM, 3, 6; RAM, 4; communication means, 5; NVRAM.

Claims (4)

Executes firmware, mask ROM that stores the address information of all functions other than the main data and fixed data referenced by the firmware and firmware, RAM that copies the address information of the functions stored in the mask ROM, and mask ROM firmware And a communication means for communicating with the outside, the address information of the function stored in the mask ROM is copied to the RAM at startup, and the function call when the CPU executes the firmware of the mask ROM is RAM A firmware update method for an embedded information processing apparatus configured to operate based on address information of a function copied to
The firmware has a function of writing data input from the communication means to an arbitrary address on the RAM. When the firmware of the mask ROM is changed or added, the modified firmware or the firmware to be added is externally connected to the communication means. A method for updating embedded firmware, wherein the firmware that corrects or adds the address information of the corresponding function copied to the RAM and the address information of the newly written RAM is rewritten to the address information of the newly written RAM.   2. The embedded firmware update method according to claim 1, wherein the factory-dedicated firmware for factory adjustment before factory shipment is written in an empty area of the RAM. Firmware, fixed data referenced by the firmware, and mask ROM storing address information of all functions other than the main routine, NVRAM in which address information of functions stored in the mask ROM is copied, and RAM as a data area , Equipped with a CPU for executing the mask ROM firmware and communication means for communicating with the outside. At startup, the function address information stored in the mask ROM is copied to NVRAM, and the CPU executes the mask ROM firmware. The function call is a firmware update method in an embedded information processing apparatus configured to operate based on address information of a function copied to NVRAM,
The firmware has a function of writing data input from the communication means to an arbitrary address on the NVRAM. When the firmware of the mask ROM is changed or the firmware is added, the modified firmware or the firmware to be added is communicated from the outside. A method for updating embedded firmware, characterized in that the address information of the corresponding function written in the NVRAM and modified or added to the NVRAM is rewritten to the newly written NVRAM address information through the means.   4. The embedded firmware update method according to claim 3, wherein the dedicated firmware for factory adjustment before factory shipment is written in an empty area of the NVRAM.

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