JPH0476795A - Ic card - Google Patents

Abstract

PURPOSE:To easily change a program by storing a fixed subroutine in a mask ROM and storing a main routine in a programmable memory. CONSTITUTION:Many highly versatile subroutines 312 and a main routine writing program 32 are stored in the mask ROM 3 and a CPU executes the program 32 at first. In the program 32, a main routine writing command is received from an I/O terminal, and if the command is not received, the main routine 52 is executed. When the command is received, a main routine writing mode is set up and a program to be received from the I/O terminal is written in the programmable memory 5 to end the program 32. Consequently, the program can easily be changed without changing the contents of the mask ROM 3.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an IC card that has a built-in microcomputer (hereinafter referred to as a microcomputer) and a programmable memory, and allows the microcomputer to execute a program written in the programmable memory. It is.

[Conventional technology]

FIG. 4 is a block diagram of a conventional IC card, and FIG. 4 is a memory map of the IC card shown in FIG.

In the above, +1I is an IC card, (21 is an IC card (1) is a CPU that controls the entire system, (3) is a mask ROM in which the hub program is stored, +41i is a RAM in which calculation results and data are stored, +51 is a RAM in which fD data is stored. Programmable memo!J, +61 is an input/output control circuit that exchanges data with the outside, (7) is a bus that transmits data address control signals, etc. to each block, +81
fl VCC terminal that supplies power to the IC card il+, (9) is the GND terminal, 101 is the reset terminal that resets the IC card fil, (a friend clock terminal that supplies the Illill Microk KLC card il+, Q21fl A companion terminal for exchanging data with the outside, (31) a program stored in the Hamask ROM +31, and data stored in the programmable memory (6). The main routine (311) and subroutine (312) in the program stored in the mask ROM +31 shown in FIG.

Next, the operation will be explained. First, IC card 111G
'! "It starts operation by being supplied with power from the /cc terminal 18+ and the GND terminal (9), by being supplied with a clock signal between the clock terminals, and by being supplied with a reset signal by the reset terminal αα. After that, the operation is started by being supplied with a reset signal from the reset terminal αα. Data transfer is performed under the control of the input/output control circuit 1B).A program ell to be executed by the u CPU +21 is stored in the mask ROM i3).
12+ Reads and executes the program system via the U bus (7). Program executed by CPU 121 (31
1U main routine (311) is also a subroutine (3 schools)
are all stored in mask ROM +31. C.P.
Execute the U tz+ tj main routine (311),
Main routine (311) to subroutine (312)
Call and execute. This is shown in FIG.

In addition, the CPU tel sends calculation results etc. to R as needed.
AM+41 or data @ to the programmable memory (6).

[Problem to be solved by the invention]

Since the conventional IC card is configured as described above,
All programs, both main routines and subroutines, are stored in the mask ROM, so if you want to change the program, be sure to change the mask ROM f.
This method requires a large amount of cost and cannot be used in small-scale IC card systems because it cannot handle high-mix, low-volume production.

This invention has been carefully designed to solve the above-mentioned problems, and an object of the present invention is to obtain an IC card whose program can be easily changed and which does not require changing the mask ROM.

[Means to solve the problem]

In the IC card according to the present invention, a fixed subroutine is stored in the mask ROM, and a main routine is stored in the programmable memory.

[Effect]

The IC card according to the present invention stores the main routine in the programmable memory, so that the program can be easily changed without changing the mask ROM.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 [IC card memory map, Figure 2, Figure 11A]
FIG. 3 is a diagram showing the execution costs of the main routine and subroutines stored in the mask ROM shown in FIG.

In the figure, (3) to +51, @, scratch η, (3
12) is the same as that shown in the conventional example shown in FIGS. 4 to 6, so the explanation will be omitted. This is the main routine stored in the programmable memo (January 5). Third
This figure is a flowchart of the main routine writing program shown in FIG.

Next, the operation will be explained. The mask ROM +31 stores a large number of highly versatile subroutines (312) and a main routine writing program.
U +2114 First, execute the main routine JiF import program □□□. Main routine writing program (at step 32, a main routine writing command is first received from the I10 terminal Ot. If this command is not received, the main routine @ is executed.

When the command is received, the program enters the main routine write mode, writes the program received from the i10 terminal a into the programmable memory (6), and then ends the main routine write program.

When executing the main routine, the main routine @ written in the programmable memory (6) is executed sequentially from the beginning, and then stored in the mask ROM +31 by the subroutine call and executed as the subroutine (312).
> Execute.

Note that the above example shows that the execution of the main routine writing program is performed by receiving the main routine writing command from the I10 terminal (121). If there is no main routine, writing to the main routine is prevented, which provides higher security than the above embodiment.

〔Effect of the invention〕

As described above, according to the present invention, the main routine can be easily changed without changing the mask ROM, so the cost of changing the program can be reduced, and it is also possible to support small-scale, high-mix production. It is possible to supply all IC cards to an IC card system, and the delivery time for program changes can be shortened, resulting in an advantageous effect.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a memory map of an IC card according to an embodiment of the present invention, FIG. 2 is a diagram showing execution of the main routine and subroutines stored in the mask ROM shown in FIG. 1, and FIG. Figure 1 shows the flowchart of the main routine writing program, and Figure 4 shows the conventional IC.
A block diagram of the card, FIG. 5 shows the memory map of the IC card shown in FIG. 4, and FIG. 6 shows the mask RO shown in FIG. 4.
FIG. 3 is a diagram showing the execution of a main routine and subroutines stored in M. In the figure, (3) is a mask ROM, and +41 is a RAM.
, +51 is a programmable memory, Soni main routine writing program, (9) is data, Sabaji main routine, (311'') is a main routine, and (312) is a subroutine. In addition, in the figure, the same symbols are the same, ◇ Figure 1 3 Maz'tROM 4: RAM l1l: Subroutine Figure 3 Figure 4 1-----11C11-2: CPU Output Control Immediate Cause 1/Q Connection Figure 6 Figure 5 October 26, 1990

Claims (1)

[Claims] An IC that is equipped with a microcomputer, a mask ROM that stores programs to be executed by the microcomputer, and a programmable memory that stores data, and that can execute programs written in the programmable memory.
An IC card characterized in that only a subroutine is stored in a mask ROM, and a main program is stored in a programmable memory.