JP2000305771A - Method for loading software to microcomputer incorporating nonvolatile memory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of a loader program by loading an application program by means of the execution of the second loader program after loading the second loader program by means of the execution of the first loader program. SOLUTION: The first loader program receives the code of the second loader program from a host side after the initialization setting processing of a register or the like in a microcomputer and the initialization setting processing of a communication device and stores the code in an external SRAM 106. A host side computer 101 reads the code of the second loader program from a hard disk 102 after the initialization processing of a communication interface 103 and transmits it to the side of the microcomputer. A microcomputer side receives the code of the application program from the host side computer 101 and stores it in a flash memory 105 incorporated in the microcomputer. Then the host side transmits the code of the application program to the microcomputer side by linkage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of downloading a program, and more particularly, to a method of loading software into a microcomputer with built-in nonvolatile memory.

[0002]

2. Description of the Related Art A conventional software download method for a microcomputer with a built-in nonvolatile memory such as a flash memory is disclosed in Japanese Patent Application Laid-Open No. 6-44064, in which an application program code to be written to a flash memory is temporarily stored in an SRAM. Then, after the flash memory is collectively erased, the code in the SRAM is moved to the flash memory and stored.

[0003]

However, the above-mentioned software loading method stores a code of an application program in an SRAM, erases the flash memory at a time, and then stores the code in the SRAM in the flash memory. Loader program) is stored in an external ROM.
In recent years, microcomputers with built-in flash memory have become widespread,
Instead of storing the loader program in the external ROM, a configuration in which a specific block of the flash memory is reserved for storing the loader program has been used, but the size of storing the application program is large. There was a problem that it would decrease.

Accordingly, the present invention has been made in view of the above problems, and has as its object to provide a loading method for reducing the size of a loader program.

[0005]

In order to achieve the above object, the present invention provides a loader program that writes a code of an application program into a flash memory (a second loader program), and a program that executes the second loader program. A program (first loader program) for loading the code into a RAM built in the microcomputer with built-in flash memory or an external RAM, and after loading the second loader program by the first loader program, It has a procedure for loading an application program by a loader program.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, a loader program is a program for writing code of an application program to a flash memory (a second loader program).
And a program (a first loader program) for loading the code of the second loader program into a RAM built in the microcomputer with a built-in flash memory or an external RAM (second loader program). It has a procedure for loading the application program by the second loader program after loading the program. According to this method, only the first loader program needs to be stored in the ROM in advance, and Since the loader program is loaded into the RAM and executed, the size of the loader program stored in the ROM can be made much smaller than that of the prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a flash memory loading device according to a first embodiment of the present invention. Reference numeral 101 denotes a host computer such as a personal computer, and a hard disk of 102 stores a file storing application program codes.
Reference numerals 103, 104, and 105 denote circuit blocks of a communication interface, a CPU core, and a flash memory, respectively, which constitute the microcomputer chip. Here, the communication interface may be any communication interface such as a serial interface or a parallel interface capable of exchanging data with the outside of the microcomputer, and its specifications are not particularly defined. Reference numeral 106 denotes a rewritable memory such as an SRAM.

The memory map shown in FIG. 2 includes a memory block 201 for storing a first loader program, a flash memory block 202 for storing an application program, and a memory area 203 arranged as an external memory. Used to store programs. The first loader program may be stored in a ROM or by using one or more blocks of a flash memory. When storing data using one or more blocks of the flash memory, the data is written in advance using an LSI tester or the like. Although the arrangement shown here is merely an example showing the arrangement of the components of the software, it should be noted that the size of each element is generally larger in the second loader program than in the first loader program. This is because the second loader program includes a procedure for writing to the flash memory, and thus includes a complicated processing procedure.

Next, the processing procedure of the first and second loader programs and the processing of the control software of the host computer will be described in detail with reference to the flowchart of FIG. Normally, the microcomputer with built-in flash memory starts the loader program by releasing the reset after setting the mode by setting external pins. As described above, the loader program is configured to be largely divided into a first loader program 201 and a second loader program 203.
First, initialization setting processing of microcomputer registers and the like S301
After performing the communication device initialization setting process S302, the code of the second loader program 203 is received from the host and stored in the external SRAM 106 (S3).
03). On the other hand, after the initialization processing S305 of the communication interface 103, the host computer 101 reads the code of the second loader program 203 from the hard disk 102 and transmits it to the microcomputer side (S306).
The process of S303 and the process of S306 are processes that cooperate with each other. However, since they are known technologies, detailed description will be omitted. Next, the microcomputer transmits the code of the application program 202 to the host computer 10 in S304.
1 and the flash memory 105 built in the microcomputer.
To be stored. In S307, the host transmits the code of the application program 202 to the microcomputer in cooperation with the host. The processing method of storing data in the flash memory 105 is realized by a complicated processing procedure.
This is performed using a method as described in US Pat. The size of the processing code in S304 is generally considerably large due to its complexity.

By performing the above processing, the application program can be downloaded to the flash memory.

[0012]

As described above, according to the downloading method according to the present invention, the loader program to be stored first using one or more blocks of the ROM or the flash memory of the microcomputer has a complicated processing procedure. And the effect of reducing the size can be obtained.

Furthermore, since complicated processing for storing data in the flash memory can be stored in the hard disk of the host computer without being stored in the ROM or a specific block of the flash memory, it is easy to make changes, and parameters for writing conditions of the flash memory can be easily changed. It is possible to obtain an effect that the change and the algorithm can be easily changed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a flash memory loader device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a memory map of a flash memory and a RAM according to the embodiment of the present invention;

FIG. 3 is a flowchart of a loading method according to an embodiment of the present invention;

[Explanation of symbols]

 Reference Signs List 101 host computer 102 hard disk 103 communication interface 104 CPU core 105 flash memory 106 RAM 201 first loader program 202 application program 203 second loader program

Claims (2)

[Claims] 1. A method for loading an application program into a nonvolatile memory of a microcomputer with a built-in nonvolatile memory, comprising: a program (second loader program) for writing code of the application program into the nonvolatile memory; A program (first loader program) for loading a program code into a RAM built in the nonvolatile memory microcomputer or an external RAM, after loading the second loader program by executing the first loader program; And loading the application program by executing the second loader program. 2. The method according to claim 1, wherein the nonvolatile memory is a flash memory.