JPH07311758A - Semiconductor integrated circuit and portable electronic equipment using the same - Google Patents

Abstract

PURPOSE:To save current for precharging and to reduce the current consumption of a microprocessor in operation by precharging only a divided instruction decoder corresponding to an instruction to be decoded. CONSTITUTION:The signal line-4 in an instruction signal group 5 which corresponds to the MSB(most significant bit) is connected to a precharge decoding circuit 7, and precharge 3 is inputted to the other input of the precharge decoding circuit 7. The outputs of the precharge decoding circuit 7 are signals 12 and 13 and connected to precharge control transfer groups 9 and 10, which are connected to instruction decoders 1 and 2. This precharge decoding circuit 7 activates the precharge signal 12 or 13 corresponding to a currently inputted d instruction and controls the precharge control transistor group 9 or 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microprocessor and a device using the same, or a memory and a device using the same.

[0002]

SUMMARY OF THE INVENTION The present invention saves precharge current by operating a microprocessor or memory by dividing a decoder and precharging the decoder only for the divided decoder corresponding to an instruction or address signal to be decoded. In this case, the current consumption of the semiconductor integrated circuit is reduced.

[0003]

2. Description of the Related Art Conventionally, there have been known methods for reducing the power consumption of a microprocessor, such as lowering of voltage or CMOS, and further, a method of suspending a clock signal while the processing of the microprocessor is not required, a so-called sleep state is known. It was being done.

[0004]

However, the prior art sleep has a drawback that it is disabled when the microprocessor is operating. SUMMARY OF THE INVENTION The present invention has an object to reduce current consumption during microprocessor operation in order to solve the conventional drawbacks described above.

[0005]

In order to solve the above problems, the present invention focuses on an instruction decoder in a microprocessor and divides the instruction decoder to reduce the current consumption and decode the precharge of the instruction decoder. Is performed only in the divided instruction decoder corresponding to the instruction to save the precharge current and reduce the current consumption of the microprocessor during operation.

Since the semiconductor integrated circuit of the present invention has a low current consumption, when this semiconductor integrated circuit is used in a portable electronic device driven by a battery, it has an effect of prolonging the battery life. The portable electronic device may be any electronic device that is driven by a battery. As a portable electronic device to which the present invention can be applied,
Examples include remote controllers, electronic notebooks, personal computers, word processors, VTRs, mobile phones, cameras, CD players, MD players, radios, and game consoles.

[0007]

With respect to the instruction input to the microprocessor, the instruction is decoded by the instruction decoder via the instruction register for temporarily storing the instruction, and various operations or data transfer are performed.

In order to decode the instruction in the instruction decoder,
It is necessary to precharge the structured instruction decoder for a predetermined period. Here, the instruction decoder is divided into a plurality of groups, and an instruction input to the instruction register is generated by a selection signal decoder circuit corresponding to the instruction decoder divided in front of the instruction register, and is generated by this selection signal and the timing controller. Signal is used to precharge only a necessary part of the divided instruction decoder. At this time, the precharge is not performed on the unnecessary divided instruction decoders. As a result, the current consumed by precharging can be saved.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an embodiment of the present invention. Reference numeral 5 in FIG. 1 denotes a command signal group. These signals are input to the D input of the latch group 8. The clock of the latch is obtained by inverting the clock signal 6 by the inverter 11, and the clock signal 6
The command signal group is latched at the falling edge of.
The output signals are output from the Q output of the latch group 8 and become the latch output signal group 15, which are input to the instruction decoders 1 and 2.

The instruction decoder output signal group 16 which is the output of the instruction decoders 1 and 2 is input to the D input of the latch group 14 and latched by the clock signal 6. This output is output from the Q output of the latch group 14 and used as a control signal. MS of command signal group 5
The signal line 4 corresponding to B (Most Significant Bit) is input to the precharge decoding circuit 7. The precharge 3 is input to the other input of the precharge decode circuit 7.
The outputs of the precharge decode circuit 7 are 12 and 13, respectively, and the precharge control transistor groups 9 and 10 respectively.
Connected to. Precharge control transistor groups 9 and 10 are connected to instruction decoders 1 and 2, respectively. The precharge decode circuit activates the precharge signal 12 or 13 corresponding to the instruction that is being input, and controls the precharge control transistor group 9 or 10, respectively.

As a result, the instruction decoder 1
Only the one you need can be supplied.

[0012]

As described above, the present invention has the effect of reducing the current consumption of the operating microprocessor. Further, since the current consumption of the portable electronic device using the semiconductor integrated circuit of the present invention can be reduced, the life of the battery used as a power source can be extended.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a timing diagram of the present invention.

FIG. 3 is a circuit diagram illustrating a conventional technique.

[Explanation of symbols]

 1, 2 Instruction decoder 3 Precharge signal 4 Command signal MSB (Most Significant Bit) 5 Command signal group 6 Clock signal 7 Precharge decode circuit 8 Latch group 9, 10 Precharge control transistor group 11 Inverter 12, 13 Precharge decode circuit Output 14 Latch group 15 Latch output signal group 16 Instruction decoder output signal group

Claims (8)

[Claims] 1. A microprocessor having an instruction register for temporarily storing an instruction input to a microprocessor, an instruction decoding unit for decoding the instruction, and a timing controller necessary for operating the instruction decoder, wherein the instruction decoder is provided. Is divided into a plurality of groups, an instruction input to the instruction register is generated with a selection signal corresponding to the instruction decoder divided in front of the instruction register, and this signal and the signal generated by the timing controller cause the instruction decoder A semiconductor integrated circuit characterized by precharging only a necessary part of the above. 2. The semiconductor integrated circuit according to claim 1, wherein the instruction grouping and the instruction decoder corresponding to the instruction grouping are divided according to the frequency of use of the instructions used in the program for operating the microprocessor. circuit. 3. A memory having an address latch for temporarily storing an address input to the memory, an address decoding unit for decoding the address, and a timing controller necessary for operating the address decoder, wherein a plurality of the address decoders are provided. The address input to the address latch is divided into groups, and a selection signal corresponding to the address decoder divided before the address latch is generated. This signal and the signal generated by the timing controller select the address decoder. A semiconductor integrated circuit characterized by precharging only necessary portions. 4. The semiconductor integrated circuit according to claim 1, wherein the grouping of the addresses and the corresponding grouping of the address decoders are divided according to the frequency of use of the addresses used in the program for operating the memory. . 5. A microprocessor having an instruction register for temporarily storing an instruction input to the microprocessor, an instruction decoding section for decoding the instruction, and a timing controller necessary for operating the instruction decoder, wherein the instruction decoder is provided. Is divided into a plurality of groups, an instruction input to the instruction register is generated with a selection signal corresponding to the instruction decoder divided in front of the instruction register, and this signal and the signal generated by the timing controller cause the instruction decoder A portable electronic device characterized by using a semiconductor integrated circuit for precharging only a necessary part of the circuit. 6. A semiconductor integrated circuit is used in which instruction groups and instruction decoders corresponding thereto are divided according to the frequency of use of instructions used in a program for operating a microprocessor. Item 5. The portable electronic device according to item 5. 7. A memory having an address latch for temporarily storing an address input to the memory, an address decoding unit for decoding the address, and a timing controller necessary for operating the address decoder, wherein a plurality of the address decoders are provided. The address input to the address latch is divided into groups, and a selection signal corresponding to the address decoder divided before the address latch is generated. This signal and the signal generated by the timing controller select the address decoder. A portable electronic device using a semiconductor integrated circuit for precharging only a necessary portion. 8. A semiconductor integrated circuit is used in which the grouping of addresses and the corresponding grouping of address decoders are divided according to the frequency of use of addresses used in programs for operating a memory. 5
The portable electronic device described.