JP2001147863A - Flash memory rewrite device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flash memory rewrite device capable of communicating with an outside tool even when the rewriting of a user program including a communication program fails. SOLUTION: An emulation device 1 is provided with an evaluation chip 2, a flash memory 3 and an emulation RAM 4. The flash memory 3 stores a prescribed user program including a program for communicating with an outside tool 10. Firmware is operated by the EVA chip 2 so that communication with an outside tool can be attained according to a writing request from the outside tool 10. At that time, a user program in the flash memory 3 is rewritten by the EVA chip 2, and whether or not the rewriting of the user program is normally ended is judged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash memory rewriting device having a flash memory for storing a predetermined program and rewriting the program.

[0002]

2. Description of the Related Art Conventionally, as this type of device, a communication program for communicating with an external tool is stored in a partial area of a flash memory together with a user program.
It is known to rewrite a flash memory program using the communication program.

More specifically, a microcomputer (flash memory rewriting device) 20 shown in FIG.
1 and a RAM 22. Flash memory 2
1 stores a user program for executing various controls. The user program has a communication program in a part thereof, and communication between the microcomputer 20 and the external tool 23 is performed by processing the communication program.

When a user program is rewritten, a rewrite request is issued from the external tool 23 to the microcomputer 20, as shown in FIG. Then, as shown in FIG. 6B, the microcomputer 20 executes the communication program to execute the external tool 23 or the rewriting program prepared in the microcomputer 20 in advance.
Transfer to AM22. Thereafter, as shown in FIG. 6C, the microcomputer 20 executes the rewriting program on the RAM 22 to temporarily load the new user program including the communication program from the external tool 23 into the RAM 22 and store the new user program in the flash memory 21. It is rewritten.

[0005]

However, when the user program including the communication program is rewritten by the above-described rewriting method, if the rewriting of the flash memory 21 fails due to the influence of power cutoff, noise, or the like,
A program that does not operate correctly exists in the flash memory 21. That is, the flash memory 2
No. 1 does not have a normal communication program, so that the flash memory 21 cannot be rewritten.

Therefore, conventionally, as a method for avoiding this, a method is employed in which an area for storing a program for communicating with the external tool 23 is not erased, but the other area is rewritten.

Incidentally, the flash memory 21 is divided into a plurality of blocks, and at the time of rewriting, data is erased for each block. Specifically, as shown in FIG. 7, in the flash memory 21 having a storage capacity of 256 kilobytes (KB), for example,
It is divided into four 4 KB blocks 21a, and data is erased for each block 21a. Further, the communication program stored in the flash memory 21 usually has a size of 2 to 4 KB. Therefore, as described above, if the method of not erasing the area storing the communication program is adopted, the block size (64 KB) that is not erased for the communication program (2 to 4 KB) becomes unnecessarily large, and the storage area is wasted. Problem.

The present invention has been made in view of the above problems, and has as its object to communicate with an external tool even if rewriting of a user program including a communication program fails. It is an object of the present invention to provide a flash memory rewriting device capable of performing the above.

[0009]

According to the first aspect of the present invention, communication with an external tool is performed by a communication unit in response to a rewrite request from the external tool. At this time, the user program stored in the flash memory is rewritten by the rewriting means. The determining means determines whether or not the rewriting of the user program has been normally completed, and stores the determined result. In this case, even if rewriting of the flash memory fails, it can be determined, and at that time,
Communication with an external tool can be performed by communication means provided separately from the communication program. That is, it is possible to communicate with an external tool without going through a communication program that cannot operate normally when the rewriting fails. As a result, there is no inconvenience that the user program cannot be rewritten, and the user program can be properly rewritten.

According to the second aspect of the invention, when it is determined that the rewriting of the user program is not completed, the execution of the user program is prohibited. On the other hand, when it is determined that the rewriting of the user program has been completed normally, execution of the user program after the completion of the rewriting is permitted. In this case, it is possible to prevent the user program whose rewriting has failed from being executed by mistake.

According to the third aspect of the invention, the rewrite state of the user program is stored in the flash memory. That is, since the user program and the rewrite state of the flash memory are stored in the common flash memory, the cost of the user program and the rewrite state of the flash memory are lower than those stored in separate memories. This is advantageous.

According to the fourth aspect of the present invention, communication between the external tool and the external tool is performed by firmware executed at the time of startup, and at this time, the user program in the flash memory is rewritten. That is, communication with the external tool can be performed by firmware executed before the user program, and the user program can be appropriately rewritten.

According to an emulation apparatus for emulating a user program stored in a flash memory, a user program in a flash memory is emulated in an emulation RAM.
And emulation of the user program is performed. In this device, the emulation RAM
By writing the above user program into the flash memory, the flash memory can be rewritten. Specifically, a new user program transferred from an external tool onto the emulation RAM or a user program on the emulation RAM changed by emulation can be rewritten to the flash memory.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, the present invention is embodied in an emulation device applied when developing a vehicle control system.

The vehicle control system includes an electronic control unit (EC)
U), and various controls are performed by a microcomputer mounted on the electronic control device. Therefore, in the development stage of the vehicle control system, it has a function equivalent to the microcomputer used in the system and has an emulation function in order to adapt the control data in the user program incorporated in the microcomputer to the optimum value. An emulation device is used. The emulation device according to the present embodiment is realized as a multi-chip module (MCM) in which a plurality of semiconductor chips constituting functional blocks are densely mounted on one substrate, and the emulation device is an electronic control device (MC). E
CU).

FIG. 1 shows a schematic configuration of an emulation device 1 according to the present embodiment. As shown in FIG.
The emulation device 1 includes an evaluation chip (hereinafter, referred to as an evaluation chip) 2 and a flash memory 3.
And an emulation RAM (hereinafter referred to as E_RAM) 4.

The evaluation chip 2 has an emulation function in addition to functions equivalent to those of a microcomputer used in a control system during mass production. In other words, the evaluation chip operates in the same manner as the mass-production microcomputer to operate as a substitute for the mass-production microcomputer, as well as the CPU, RAM, backup RAM, timer, A / D
A converter, an SCI, and the like are provided. The flash memory 3 stores firmware that is fixed to hardware and is executed at the time of startup, and a user program for performing predetermined control. The E_RAM 4 is provided for emulating a user program stored in the flash memory 3.

The evaluation chip 2, the flash memory 3, and the E_RAM 4 are connected by a bus 5. Then, the flash memory 3 and the E_RA
Address designation for M4 and transfer of data between the evaluation chip 2, the flash memory 3, and the E_RAM 4 are performed on the bus 5
Done through.

The external tool 10 is a device for outputting a flash write command or the like to the emulation device 1, and is composed of, for example, a general-purpose personal computer. The external tool 10 has a display unit 10a for displaying a message.
Is provided.

The emulation apparatus 1 according to the present embodiment includes an NBD (Non Break Debugger) module (for example, an AUD module of SH7055 manufactured by Hitachi, Ltd.). In response to the request, the data writing / reading of the E_RAM 4 can be directly performed without the intervention of the CPU in the evaluation chip 2.

The flash memory 3 used in this embodiment has a storage area of 1 megabyte (MB).
As shown in FIG. 2, the configuration is such that 51
It consists of an area of 2 kilobytes (KB) and an area of 512 KB allocated as a storage area Y for storing a user program including a communication program.

In the storage area X, an area X1 for storing firmware and an area X2 for storing a rewrite state of the flash memory 3 are secured. The rewriting state of the flash memory 3 is data indicating whether or not the rewriting operation has been completed normally at the time of the rewriting. The rewriting state is such that predetermined 16-bit data, for example, is stored in the area X2. Has become. Also, E_RAM4 is
The flash memory 3 has the same 512 KB storage area as the user program storage area Y.

In the emulation apparatus 1 configured as described above, the user program in the storage area Y of the flash memory 3 is transferred to the E_RAM 4, and emulation of the user program is performed.
Further, at the time of emulation, by using the NBD module, E_R
The control data on AM4 is adapted to the optimal value. In addition,
Each of the storage areas X and Y is composed of eight blocks of 64 KB, and data is erased for each block when the flash memory 3 is rewritten.

Here, the operation when the user program stored in the flash memory 3 is transferred to the E_RAM 4 and emulation is performed will be described. When the system is started, firmware is executed by the CPU of the evaluation chip 2, and the user program in the storage area Y of the flash memory 3 is transferred to the E_RAM 4. And
By causing the program counter of the evaluation chip 2 to transition to the E_RAM 4, the user program of the E_RAM 4 is executed. In the emulator 1, after the program counter is shifted to the E_RAM 4, the flash memory 3 is disconnected from the bus 5, and the evaluation chip 2 cannot access the flash memory 3 again. That is, at the time of emulation, E_R
Communication between the emulation device 1 and the external tool 10 is performed by a communication program on the AM 4.

Next, the operation of rewriting a user program in the flash memory 3 with a new user program will be described with reference to FIG. FIG. 3 shows a process for rewriting an old user program stored in advance in the flash memory 3 with a new user program.

As shown in FIG. 3A, a rewrite request is issued from the external tool 10 while the old user program on the E_RAM 4 is being executed. Then, the evaluation chip 2 receives the rewriting request by the communication program of the E_RAM 4, sets the “flash rewriting mode” in the backup RAM in the evaluation chip 2,
Then reset the system. Specifically, a reset signal is output by the evaluation chip 2, and a reset circuit (not shown) operates based on the reset signal to reset the system. When the system is restarted after this reset, the evaluation chip 2
Execute the firmware stored in. This allows
The rewriting of the user program storage area Y of the flash memory 3 is performed. In this rewriting process, by using the function of the NBD module, as shown in FIG.
_RAM4 is written directly. Then, as shown in FIG. 3C, the contents of the E_RAM 4 are stored in the flash memory 3.
, The flash memory 3 is rewritten with a new user program.

In the emulation apparatus 1 of the present embodiment, in addition to the above-described rewriting of a new user program, for example, rewriting of control data more suitable for emulation can be performed. That is, after the emulation, the contents of the partial area of the E_RAM 4 can be written in a predetermined block of the user program storage area Y.

Next, among the processing executed by the evaluation chip 2, the processing of firmware executed when the system is started will be described in detail with reference to the flowcharts of FIGS. First, in step 100, the evaluation chip 2 determines the operation mode set in the backup RAM in the evaluation chip 2, and when the operation mode is determined to be the flash rewriting mode, the process proceeds to step 110 to perform the rewriting process. This rewriting process is performed as shown in FIG.
In step 11, the operation mode of the backup RAM is changed from the flash rewrite mode to the user program execution mode as initialization processing. Continue with step 11
2, the evaluation chip 2 outputs “H′FFF” indicating the unwritten state as data indicating the flash rewritten state.
F ”is written in the area X2 of the flash memory 3. Then, the process proceeds to step 113, where the evaluation chip 2 erases the data in the user program storage area Y, and then writes the new user program transferred from the external tool 10 to the E_RAM 4 in the user program storage area Y. In addition, in order to confirm that the writing was successful,
Verify processing is performed. That is, it is determined whether the contents of the E_RAM 4 and the contents written in the storage area Y of the flash memory 3 are the same. If the contents of the E_RAM 4 and the contents written to the flash memory 3 do not match in this verification processing, the processing of writing a new user program is performed again. Then, when the writing is completed normally, the evaluation chip 2 writes “H′AA55” indicating the rewriting completed state in the area X2 of the flash memory 3 in step 114, and then ends the rewriting process.

When the rewriting of the flash memory 3 is completed, the external tool 10 issues a reset command to the emulation device 1. The evaluation chip 2 outputs a reset signal to a reset circuit (not shown) based on the reset command, and the system is reset based on the signal.

Thereafter, when the system is started, FIG.
Is executed. In this case, in the process of step 100, the user program execution mode is determined, and the evaluation chip 2 proceeds to step 120.
In step 120, the evaluation chip 2 determines whether or not the rewriting is completed based on the value written in the area X2. Then, "H'AA55" is set in this area X2.
Has been written, and the evaluation chip 2 proceeds to step 130 when it is determined that the rewriting is completed. The evaluation chip 2 determines in step 130 that the flash memory 3
After the user program written in the storage area Y is transferred to the E_RAM4, the process jumps to the user program in the E_RAM4. That is, by shifting the program counter to the E_RAM 4, the user program on the E_RAM 4 is executed by the evaluation chip 2, and emulation of the user program is performed.

On the other hand, the flash rewriting process (FIG. 5)
During the processing of steps 112 and 113), if an instantaneous power interruption or noise occurs, the processing may be interrupted while the rewriting of the flash memory 3 is not completed. In this case, the evaluation chip 2 performs step 10
When the processing shifts to the processing of step 120 after the processing of 0, the evaluation chip 2 stores the value (H′F) written in the area X2.
FFF), it is determined that rewriting is not completed, and the process proceeds to step 140. Then, in step 140,
The evaluation chip 2 waits until a rewrite request from the external tool 10 is received. At this time, the external tool 10
A message indicating an abnormal rewriting of the flash memory 3 is displayed on the display section 10a. Thereafter, when a rewrite request is issued from the external tool 10 in response to an operation of a worker or the like, the evaluation chip 2 proceeds to step 110 and executes the flash rewrite process again.

As described above, it is determined whether or not the rewriting of the flash memory 3 has been completed normally. When it is determined that the rewriting of the user program has not been completed, the E_RAM 4
Transfer of the user program to the E_RAM
4 execution of the user program is prohibited. On the other hand, when it is determined that the rewriting of the user program has been completed normally,
The data is transferred to the RAM 4 and the execution of the user program on the E_RAM 4 is permitted.

When the control data adapted by emulation is written back from the E_RAM 4 to the flash memory 3, the system is reset after setting the operation mode to the flash rewrite mode. Thereafter, the processing shown in FIGS.
The contents of the RAM 4 are rewritten to the flash memory 3.

In this embodiment, the evaluation chip 2 corresponds to the rewriting means, and the firmware corresponds to the communication means. Further, the processing of step 120 corresponds to the determination means. The present embodiment described above has the following features.

(1) Communication with the external tool 10 is performed by firmware executed at the time of startup. At this time, the user program in the flash memory 3 is rewritten. Further, it is determined whether or not the rewriting of the flash memory 3 has been normally performed. In this case, even if the rewriting of the user program in the flash memory 3 fails, it can be determined. At that time, communication with the external tool 10 can be performed by firmware provided separately from the communication program. it can. That is, when the rewriting fails, communication can be performed with the external tool 10 without going through a communication program that cannot operate normally. As a result, there is no inconvenience that the user program cannot be rewritten, and the user program can be properly rewritten.

(2) The rewriting state of the user program is determined, and execution of the user program is prohibited until the rewriting is normally performed. As a result, the execution of the user program whose rewriting has failed can be reliably prevented.

(3) If a method of not erasing a block storing a communication program is adopted as in the prior art,
In some cases, the storage area for the user program is wasted, but in the emulation apparatus 1 of the present embodiment, it is not necessary to provide an area in the user program storage area Y that is not erased for the communication program. That is, the user program storage area Y can be used effectively.

(4) Since the emulation device 1 is systematized as a multi-chip module, it is hardly affected by noise and the like, so that signal transmission can be performed at high speed and mounting efficiency can be improved.

The present invention can be embodied in the following forms other than the above. In the above embodiment, the flash memory 3
In this example, firmware, data indicating a rewrite state, and a user program are stored, but the present invention is not limited to this. The data representing the firmware and the rewrite state may be stored in a memory different from the flash memory that stores the user program. Specifically, for example, firmware is stored in an EPROM, data indicating a rewrite state is stored in an EEPROM, and a user program is stored in a flash memory. However, storing the firmware, the rewrite state, and the user program in one flash memory 3 as in the above embodiment is more advantageous in terms of cost.

Generally, the emulation device 1
The flash memory 3 is manufactured without a user program written in the user program storage area Y. When the emulation device 1 is new, a value "H'FFFF" indicating an unwritten state may be written in the area X2 of the flash memory 3 before use. In this case, when the emulation device 1 is used for the first time, it is possible to reliably prevent the contents of the storage area Y in which the user program is not written from being transferred to the E_RAM 4.

In the above embodiment, the emulation device 1 is embodied as a flash memory rewriting device, but the present invention is not limited to this. In short, any device that has a flash memory for storing a user program and is embodied in a device that rewrites the user program may be used.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an outline of an emulation device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a flash memory and E_RAM.

FIG. 3 is a diagram illustrating a rewriting operation of the flash memory.

FIG. 4 is a flowchart for explaining firmware processing.

FIG. 5 is a flowchart for explaining a flash memory rewriting process.

FIG. 6 is a diagram for explaining a rewriting operation of a conventional flash memory.

FIG. 7 is a block diagram of a flash memory.

[Explanation of symbols]

1. Emulation device as flash memory rewriting device 2. Evaluation chip as rewriting device 3.
... Flash memory, 4 ... Emulation RAM, 1
0 ... external tool.

Continuation of the front page F term (reference) 5B018 GA06 HA01 KA01 KA12 NA06 QA05 QA15 RA11 RA12 5B048 AA13 BB02 5B076 EB03

Claims (5)

[Claims] 1. A flash memory for storing a predetermined user program including a program for communicating with an external tool, rewriting means for rewriting a user program in the flash memory, and a rewriting request from the external tool A communication unit that communicates with an external tool, and a determination unit that determines whether or not the rewriting of the user program by the rewriting unit has been completed normally, and stores a result of the determination. A flash memory rewriting device characterized in that: 2. The flash memory rewriting device according to claim 1, wherein the execution of the user program is prohibited when the judgment unit judges that the rewriting of the user program is not completed.
A flash memory rewriting device, wherein when the determination means determines that the rewriting of the user program has been completed normally, execution of the user program after the completion of the rewriting is permitted. 3. The flash memory rewriting device according to claim 1, wherein a result of the determination by said determination means is stored in the same flash memory in which said user program is stored. Replacement device. 4. The flash memory rewriting device according to claim 1, wherein said communication means is firmware which is fixed to hardware and executed at the time of startup. Flash memory rewriting device. 5. The flash memory rewriting device according to claim 1, wherein the user program stored in the flash memory is transferred to an emulation RAM, and the emulation of the user program is performed. Wherein the rewriting means writes a user program on the emulation RAM to a flash memory.