JPS58213362A - One-chip microcomputer - Google Patents

Abstract

PURPOSE:To increase the throughput per one application, by writing plural kinds of different programs in one program memory and using the memory exclusively so as to provide plural applications, for designating the address of program in response to the application in advance or in usage. CONSTITUTION:A memory size of a one-chip microcomputer 10 is 7FF bytes of hexadecimal H, the 1st program P1 is stored in addresses 000H-4FFH and the 2nd program P2 is stored in addresses 7FFH-600H. Further, an output of an address latch 11 of an address circuit section is applied to an address multiplexer 12, the output of which is applied to an address decoder 13. The multiplexer 12 is taken as an exclusive OR circuit, an address to the microcomputer 10 is selected by receiving a program selection control input from a pad terminal 15 and the decoder 13 designates the address of the programs P1, P2 of the microcomputer 10. Thus, the throughput per one application of the one-chip microcomputer 10 is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a 1-tep microcomputer (hereinafter abbreviated as 1-tep microcomputer).

[Technical background of the invention]

1 The microcontroller stores program memory (read-only memory: ROM), which is the basic function of computers and computers.
data memory (random access memory: RAM is used), arithmetic unit (CPU), input/output JIM (I/O/-), etc. are integrated on one semiconductor chip. It is something that For example, as shown in Figure 1 (2), a conventional L-chip microcontroller has a program memory [; one type of program P'b The content of the program P is determined depending on the purpose of the microcomputer.In this case, the program size required differs depending on the user of the microcomputer, and the data memory size required also differs. Due to reason C2, the manufacturer side) emery warpage size is different (for example, IK, 1.5K).

2, 3, Byte, etc.) usually provide several types of microcontrollers with the same architecture, so-called family development.

[Problems with background technology]

By the way, the recent trend is for products to be produced in small quantities and in a wide variety of products, and the same can be said for two microcontrollers.

However, semiconductor products such as 1-chip microcontrollers are suitable for mass production, but production of small-scale types is economically disadvantageous. Because it is dedicated, it is suitable for small-volume production application C: erasable programmable ROM (gPROM).
It is necessary to support a wide variety of products using microcontrollers, etc. with On the other hand, if small-scale production of l-chip microcomputers is carried out in the same way as mass production, excess production will have to be discarded. In any case, in the case of small-volume production8 (second), there are various problems as mentioned above, and moreover, it is necessary to prepare many processors with different memory sizes. Similar to mass production, 9 had many problems in terms of production control as 2111 mask patterns had to be prepared.

[Purpose of the invention]

The present invention is based on the above-mentioned f'#(2).
The present invention provides an l-step microcomputer that can produce relatively economical C2 even if the production amount per application is small.

[Summary of the Invention] In other words, the one-chip microcontroller of the present invention has a single program memory written with a plurality of different types of programs and is dedicated to have a plurality of uses. It is written in C2 so that the address of the program can be specified according to the purpose.

Therefore, the same chip can support multiple applications C2, 1
Even if the production volume per application is small, it can be used for multiple applications (if there are two, the required production volume can be secured, the number of millimeters can be reduced, and economical production is possible.C2).In this case, Depending on the program size, it becomes necessary to use a ROM with a large memory size, and the chip size may be sacrificed by C2, but this problem can be solved extremely easily with current LSI technology.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 shows the program "memory m" of the l-chip microcomputer and its address circuit section. The above program memo 7ztt has a memory size of 7FF bytes in hexadecimal H, for example, as shown in FIG. - In this example, two different programs P, , P, are written.

That is, for example, address 0OOH~4 FFH (the second first Grodarum P0 is also address 7 F'F'H~
600HC second grogram P is stored. On the other hand, in the address circuit section (2), the address launch 1
The output of 1 is routed to program selection circuit means such as address multiplexer 12 [2], which
[2] so that the output of the address decoder 7JC is led to the address decoder 7JC.

The multi-grec f12 is composed of, for example, an exclusive OR circuit, and one input of this OR circuit is the output of the address latch 11, and the other input is a program selection control input, such as a selection signal ``''l'' or ``0''. be guided. Therefore, when the selection signal is @O'', the multiplexer 12 outputs the input from the address latch II at the same logic level, and when the selection signal is @1'', the multiplexer 12 outputs the input from the address latch 11 at the same logic level. C2 is designed to invert the logic level of the input and output it.

Then, the control θ of C1 is set so that the selection signal 10" or 1" can be supplied from an external pin of the package, for example, according to the selection of the program P1 or P as described above.
- a line 14 and one pad terminal 15 are provided, and this terminal 15 is connected to the above external pin.

Therefore, when selecting, for example, the first program P□ corresponding to the application C2 of the l-chip microcomputer, when the microcomputer is used (by supplying the second selection signal "O", the address latch II The output from the address decoder 13 is passed through the multegrec f12 at the same logic level.
Since the output data of the address launch 11 becomes 000Hc after reset, the output data of the address launch 11 becomes C2 so as to start execution of the program PK from the address 0OOH of the program memory m.

tL[2] On the other hand, when selecting the second program P2 corresponding to the purpose of the 1-chip microcomputer (2) supplying the selection signal "1" when using the microcomputer (2), the address latch 11 Since the logic level of the output from the address latch 11 is inverted by the multiplexer f12 and guided to the address devo-/13, when the output data of the address latch 11 becomes 000H+2 after reset, the address multiplexer 12
The output data is 1111... (binary number), and the address decoder 13 selects the maximum address (1-17FFH in this example).
, thereby causing C2 to start execution of program P.

As mentioned above, by supplying the selection signal from the external pin, the user can selectively use the 1-step microcomputer for two types of purposes.

Note that the method of giving the selection signal is as per the above embodiments [not limited to two].
For example, when manufacturing a single-chip microcomputer with two wires,
Use program P□.

In response to PtC, ``lO'' level pat)', ``1'' level 1
It is also possible to connect two Cs.

In addition, although the above embodiment stores two types of programs P1 and Pt, three or more types of programs P1 #P, , P,
By storing . For example, by inserting an address adder circuit between the address latch and the address decoder, and changing the magnitude of one input of the adder circuit depending on the program being used, the program to be used can be selected (C2). One of the inputs (2r offset r-ta) of the above-mentioned adder circuit can be given at the manufacturing stage of the microcomputer (2). It is sufficient to connect one of them to the circuit, or alternatively, when used, a selection input is given from an external pin, and a plurality of input generation circuits in the chip are selected according to this selection input C2, and the address addition circuit is connected to the address addition circuit. A circuit means may be provided in the chip to provide the selection input as one input of C2, it is also possible to provide two independently operable input circuits within the chip for each function.

Further, subroutines common to a plurality of program sections may be stored in a specific address area.

According to the one-step microcontroller described above, the same chip can support two or more desired applications, and even if the production volume per application is small, the total production volume for each application is the required production volume, and large quantities can be achieved. The production C2 is cheaper than the C2.In order to be able to provide the C2, the C2 is cheaper than the C2 produced.And when such l-chip microcontrollers are expanded into families depending on the data memory size,
As in the past, the number of I/) families for each C1 application is smaller than the 7 amily number required for 27 amily expansions. Note that storing multiple types of programs in program memory requires a larger program memory size than storing only one type of program (or a general-purpose L-step microcomputer with a large program memory size). In some cases, it may be necessary to write a Niprogram and make it special, but in this case, even if the C Nitep size is sacrificed to some extent, the cost increase associated with this C2 is small according to the current LSI production technology f2. be.

〔Effect of the invention〕

As mentioned above, the microcomputer C2 of the present invention is relatively economical even if the production volume per application is small; - Adapted.

[Brief explanation of drawings]

@ Figure 1 is a diagram showing the state of program storage in the program memory of a conventional 1-chip microcomputer (2); This figure shows an example of the program storage state of the program memory in Figure 2. IO...Program memory, 12...Address multi-branch, 14°...Control line, 15...
・Pad terminal, P,,P,...program.

Claims (3)

[Claims] (1) Integrated memory, data memory, arithmetic unit, input/output device, etc. on one semiconductor chip.
In the deep microcomputer, the program memory stores a plurality of types of programs, and a selection circuit means provided in an address circuit section of the program memory for selectively designating one of the plurality of programs; An Ifg microcomputer characterized by comprising selection input means for introducing a selection control input to the circuit means. (2) The selection input means is characterized in that the selection input means inputs a selection signal externally applied to an external bin directly or after signal processing to the selection circuit means C. (3) The program memory has an address rO
A first program P8 is stored from the J address side, and a second program P8 is stored from the highest address side, and the selection circuit means selects the address signal input as it is or according to the logic level of the selection control input. Claim FM No. 1i, characterized in that it is passed through inverted.
! The one-chip microcomputer described in i.