JPH05334884A - Semiconductor device - Google Patents

Abstract

PURPOSE:To surely hold a set value to an option circuit regardless of an operation mode by holding information just before a reading means is stopped when reading operation is made to stop. CONSTITUTION:The operation setting information of the option circuit 2 is temporarily held in a information holding means 16 and a timing of a period for holding information in the information holding means 16 is set by means of a timing setting means 17. When the operation of an information reading means 12 is made to stop, the information just before the stop of operation of the information reading means 12 is held in the information holding means 16 until the time of operation recovery of the information reading means 12 based on the timing set by the timing setting means 17. Consequently, even in the operation mode such as the stoppage mode of the information reading means 12 the set value to the option circuit 2 is surely held and stable operation is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to a semiconductor device having a setting section for an external option circuit suitable for use in the field of, for example, a one-chip microcontroller. In recent years, many semiconductor devices, such as a one-chip microcontroller, having various control functions in one chip have been developed.

In such a one-chip microcontroller, an EPROM (Erasable Programmable Read Only Mem) for initial evaluation has been developed in accordance with the higher performance of the device.
There is also a chip that has a built-in non-volatile writable memory element such as a mory) and uses this non-volatile writable memory element to set an optional circuit connected to the outside of the chip. A chip having a nonvolatile writable storage element such as an EPROM is required to be usable in the same state as the mass-produced mask ROM version.

[0003]

2. Description of the Related Art FIG. 3 shows a conventional semiconductor device of this type.
There is a one-chip microcontroller with a built-in EPROM as shown in FIG. This microcontroller 1
The EPROM unit 3 is provided with the information for the option circuit 2 connected to the outside of the chip.
It comprises a sense amplifier 4, a column decoder 5, a column buffer 6, a word driver 7, a row decoder 8, a row buffer 9, and an EPPROM cell 10.

In the above configuration, the sense amplifier 4 of the EPROM section 3 storing the information for the option circuit 2
Is always enabled, the current consumption of the microcontroller 1 increases. Therefore, the microcontroller 1 is provided with an operation mode called a low power consumption mode for suppressing the total current consumption of the chip. The current consumption of the microcontroller 1 is suppressed by disabling the amplifier 4.

Then, with the recent advancement in the functionality of semiconductor devices, the microcontroller 1 for the option circuit 2
Of the terminal status options, that is, those that store information such as whether the terminal is in the input state or the output state have appeared.

[0006]

However, in such a conventional semiconductor device, since the sense amplifier 4 is configured to be disabled in the low power consumption mode, the following problems will occur. There was a point. That is, in the option circuit whose operation state changes according to the terminal state of the microcontroller 1 in the low power consumption mode, when the above-mentioned terminal state option in the low power consumption mode is enabled, the external circuit is operated in the low power consumption mode. When various settings for the option circuit 2 are changed and the option set value is determined and then the normal operation mode is restored, the information stored in the EPROM cell 10 for the option circuit 2 is read again by the sense amplifier 4, so that The setting of the terminal state option in the power consumption mode becomes invalid, and the terminal state will be different between after the option setting value is determined and after the state transition from the low power consumption mode.

Therefore, it is necessary to determine the option output when the state of the sense amplifier 4 which outputs the option is changed, that is, before the sense amplifier 4 is disabled. In the conventional one-chip microcontroller 1, this is the case. Was not considered. [Purpose] Therefore, an object of the present invention is to provide a semiconductor device that reliably holds a set value for an option circuit regardless of an operation mode.

[0008]

In order to achieve the above object, a semiconductor device according to the present invention reads information stored in an information storage means for storing operation setting information of an option circuit connected to the outside and information stored in the information storage means. The operation of the information reading means includes an information reading means, an information holding means for temporarily holding operation setting information of the option circuit, and a timing setting means for setting timing of a period for holding information in the information holding means. When stopped, information immediately before the operation of the information reading means is stopped is held in the information holding means based on the timing set by the timing setting means until the operation of the information reading means is restored.

[0009]

According to the present invention, when the operation of the information reading means is stopped, the information immediately before the operation of the information reading means is held based on the timing set by the timing setting means until the operation of the information reading means is restored. Retained by the means. That is, for example, even in an operation mode state such as a mode in which the information reading means is stopped, the set value for the option circuit is reliably held, and stable operation is obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 and 2 are diagrams showing an embodiment of a semiconductor device according to the present invention, and FIG. 1 is a block diagram showing a main configuration of the present embodiment. First, the configuration will be described.

In FIG. 1, the same numbers as the numbers given to the conventional example shown in FIG. 3 indicate the same parts. Similar to the conventional example, the microcontroller 1 which is the semiconductor device of the present embodiment stores the information for the option circuit 2 connected to the outside of the chip, the EPROM cell section 11 which is the information storing means, and the sense which is the information reading means. Amplifier unit 12, column buffer 13, row buffer 14, column gate 1
5, an EPROM section 3 having a number 5, a latch circuit 16 as an information holding means, a timing control circuit 17 as a timing setting means, and a delay circuit 18.

In the above structure, the EPROM cell unit 1
The value set to 1 is transmitted from the EPROM cell unit 11 through the latch circuit 16 when the EPROM cell unit 11, that is, the sense amplifier unit 12, the column buffer 13, the row buffer 14, and the latch circuit 16 are active. It is output to the option circuit 2. Then, in the operation mode called the low power consumption mode of the microcontroller 1, in order to suppress the total amount of current flowing through the microcontroller 1, that is, the power consumption, the sense amplifier unit 12, the column buffer 13, and the row buffer 14 which consume a large amount of current. Are disabled, and these sense amplifier section 12, column buffer 13, row buffer 14
Is stopped.

Here, in this embodiment, the EPROM cell unit 11 is changed from the normal mode to the low power consumption mode so that the output value from the EPROM cell unit 11 is fixed even in the low power consumption mode. The output value of is retained. That is, EP which is a non-volatile memory
When the option circuit 2 that operates based on the information stored in the ROM shifts from the circuit operating state to the circuit stop state, that is, when the circuit internal clock stops and shifts to the low power consumption mode, the option circuit 2 It constitutes a circuit that holds set values.

Specifically, description will be made based on a timing chart for explaining an operation example of the present embodiment in FIG.
In FIG. 2, KAP and KBP are basic clock signals in the system, PSO is a low power consumption mode signal, PS is a low power consumption mode signal PSO, and a low power consumption mode delay signal (hereinafter CK1 is a row buffer timing signal generated by inverting the basic clock signal KAP, CK2 is a latch timing signal generated from the basic clock signal KBP, and the latch timing signal CK2 is a low power consumption mode signal. The basic clock signal KBP is fixed to "H" by the PSO, so that the basic clock signal KBP is disabled.

In the present embodiment, in order to obtain the timing at which the circuit internal clock is stopped and the low power consumption mode is entered,
The delay signal PS obtained by delaying the low power consumption mode signal PSO by the delay circuit 18 is used. That is, first, the low power consumption mode signal PSO is set to "H" to shift the operation mode of the microcontroller 1 to the low power consumption mode, and after a predetermined delay time,
The delay signal PS becomes "H".

Then, the basic clock signal KBP is "H".
And the latch timing signal CK
When 2 becomes "L", the latch circuit 16 is turned off, and the information immediately before the state transition to the low power consumption mode is held in the latch circuit 16. After that, after a predetermined delay time, the delay signal PS becomes “H”, so that the sense amplifier unit 12, the column buffer 13, and the row buffer 14
Is turned off.

As a result, even when the low power consumption mode is entered, the latch circuit 16 holds the terminal information necessary for the operation of the option circuit 2, so that the output value of the EPROM cell section 11 is held stably, and In the embodiment, even when the 1-chip microcontroller 1 is in the low power consumption mode state, the setting value of the option circuit 2 is held, and the terminal option state can be changed by the setting value of the option circuit 2.

As described above, in this embodiment, the one-chip microcontroller having the option circuit 2 using the non-volatile memory (EPROM or the like) can hold the option set value even in the low power consumption mode, and the reliable terminal option function. Can be realized.

[0019]

According to the present invention, when the operation of the information reading means is stopped, the information immediately before the operation of the information reading means is stopped based on the timing set by the timing setting means until the operation of the information reading means is restored. Can be held at. Therefore, for example, even in an operation mode state such as a mode in which the information reading means is stopped, the set value for the option circuit can be reliably held and stable operation can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of the present embodiment.

FIG. 2 is a timing chart for explaining an operation example of the present embodiment.

FIG. 3 is a block diagram showing a configuration of a main part of a conventional example.

[Explanation of symbols]

 1 Micro Controller 2 Option Circuit 3 EPROM Section 4 Sense Amplifier 5 Column Decoder 6 Column Buffer 7 Word Driver 8 Row Decoder 9 Row Buffer 10 EPPROM Cell 11 EPROM Cell Section (Information Storage Means) 12 Sense Amplifier Section (Information Reading Means) 13 Columns Buffer 14 Row buffer 15 Column gate 16 Latch circuit (information holding means) 17 Timing control circuit (timing setting means) 18 Delay circuit

Claims (1)

[Claims] 1. Information storage means for storing operation setting information of an option circuit connected to the outside, information reading means for reading information stored in the information storage means, and temporarily holding operation setting information of the option circuit. An information holding unit; and a timing setting unit for setting a timing of a period for holding information in the information holding unit. When the operation of the information reading unit is stopped, based on the timing set by the timing setting unit. A semiconductor device, wherein the information immediately before the operation of the information reading unit is stopped is held in the information holding unit until the operation of the information reading unit is restored.