JPS63156218A - Microcomputer starting device - Google Patents

Abstract

PURPOSE:To miniaturize a circuit and to reduce the power consumption by supplying the clock signal of a system to the clock of a microcomputer and setting the supply voltage for the stand-by state to a low voltage value. CONSTITUTION:When a main battery 2 is set, the output OUT1 of a microcomputer CP 1 goes to a high level, and a converter 4 and a synchronizing signal generator 5 start operations; and when outputs are stabilized, the output of a reset circuit 6 goes to the high level to release the reset of the CP 1, and a mechanism or the like is initialized. When oscillation of a slow clock of the CP 1 is stabilized, the reset terminal holds the high level to inhibit the reset of the reset circuit 6, and the CP 1 switches the internal clock to a slow clock, and the output OUT1 goes to the low level to turn off the converter 4, and power is supplied from a stand-by battery 3 having a low voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a microcomputer startup device used in portable equipment such as electronic still cameras that record instantaneous images of objects on magnetic disks.

Conventional technologyPortable devices that use batteries as a power source, especially devices that do not have a main power switch for ease of operation.For example, in electronic still cameras, when a battery is installed in the device, a reset circuit is activated to control the system. The microcomputer (hereinafter referred to as microcomputer) is activated and the equipment is put on standby.

FIG. 4 is a block diagram of this conventional microcomputer startup device. 1 is a system control microcomputer that can switch between high-speed and low-speed processing and whose output terminal becomes high impedance upon reset; 101 is a system control microcomputer that supplies power to the microcomputer 1; 102 is a removable battery for the microcomputer that has a voltage value that allows the microcomputer 1 to operate at high speed. 102 is the battery 1 for the microcomputer
When 01 is newly installed, the microcomputer 1 is reset or set until the clock signal for high-speed processing of microcomputer 1 (hereinafter referred to as high-speed clock) becomes stable. 103 is a set circuit for generating a high-speed clock within microcomputer 1. A high-frequency crystal oscillator; 13 is a low-frequency crystal sensor for generating a clock signal for low-speed processing (hereinafter referred to as low-speed clock) within the microcomputer 1; 2 is a removable main battery that serves as the power source for the entire device; 4 1 is a DC-DC converter (hereinafter referred to as a converter) which receives power from the main battery 2, supplies stable voltage to each circuit system, and controls its on/off operation by the microcomputer 1; R is a microcomputer battery 101;
This is a pull-down resistor that sets the control terminal of the converter 4 to L level and prevents its operation even if the main battery 2 is installed when the microcomputer 1 is not installed or when the microcomputer 1 is reset.

In the conventional microcomputer startup device configured as described above, when the microcomputer battery 101 is newly installed, the microcomputer 1 starts to be energized, but the oscillation of the high-speed clock is unstable when the energization starts. In order to prevent the program from being executed, the reset circuit 102 applies a reset signal to the reset terminal of the microcomputer 1 and puts the microcomputer in a reset state until the oscillation of the high-speed clock becomes stable. After the reset is canceled by the reset circuit 102, the microcomputer 1 executes the program and turns on the converter 4 by turning the output port oUT1 terminal into ILHL. The main battery 2 is installed and the converter 4 is turned on. When the microcomputer 1 detects with a well-known voltage detector (not shown) that the main battery 2 is installed and the output of the converter 4 has reached the specified value, it initializes each circuit or a mechanism that operates through each circuit. After setting, when a series of system operations are not to be performed, the converter 4 is turned off, and after waiting for the low-speed clock to stabilize, the clock is switched to the low-speed side and enters a standby state in a low power consumption mode. When operating the system from this standby state, the microcomputer 1 turns on the converter 4 through the UT1 terminal, and since high-speed processing is required to control the system, the clock is switched to the high-speed side for operation.

Here, it is conceivable to supply power for the microcomputer 1 from a high-capacity main battery 2, but this main battery 2
In this case, the microcomputer 1 will be reset every time the main battery 2 is replaced. Generally, the microcomputer 1 also has calendar and time functions, so these should be reset every time the main battery 2 is replaced. There is a problem that settings must be made again, and the microcomputer battery 101 is required to solve this problem.

Problems to be Solved by the Invention However, in the above configuration, the clock is switched to a low speed side during standby mode and a low power consumption mode is entered. Since the high voltage that enables high-speed operation is still being supplied to the microcomputer 101, the current consumed by the microcomputer 1 is still large. Due to the miniaturization of devices, the current consumption of the microcomputer battery 101, which is generally small and low in capacity, is large and causes a shortened lifespan. Next, in the above configuration, even if there is a high-frequency clock signal that is essential to the system, such as in an electronic still camera, the clock signal is supplied with voltage from the converter 4 to operate, so that at the start-up time mentioned above, Considering that converter 4 is started after microcontroller 1 is started, this clock signal cannot be used as the high-speed clock of microcontroller 1, and crystal oscillator 1 is separately used for microcontroller 1.
o3 is required and becomes a factor of cost increase. Furthermore, in such a case, since two systems of high frequency signals exist asynchronously, the problem arises that the beat signals of both become noise and adversely affect the signal processing circuit of the system, such as the video signal processing circuit of an electronic still camera. . In addition, since the voltage of the microcomputer 1 and the voltage supplied by the converter 4 to each circuit differ when the system is operating, an interface such as a level conversion is required between the microcomputer 1 and each circuit to prevent damage to parts such as ICs due to voltage differences. However, this was also a problem that hindered the miniaturization and cost reduction of circuits.

As described above, the conventional microcomputer startup device has had serious practical problems.

In view of the above, the present invention is a microcomputer that enables the system clock signal to be used as the microcomputer's clock, lowers the voltage supplied to the microcomputer during standby to achieve lower power consumption, and reduces the size and cost of the circuit. The purpose is to provide a computer boot device.

Means for Solving the Problems The present invention provides a constant voltage power supply that receives power from a battery and supplies a stable voltage to each circuit, and whose on/off operation is controlled by an output port of a microcomputer;
Means for receiving voltage supply from the constant voltage power supply to generate a clock signal that can serve as a high speed clock for the microcomputer; Reset signal generating means for generating a signal to reset the microcomputer for a period of time until the output of the clock signal becomes stable; and means for operating the constant voltage power supply regardless of the output of the output port when resetting the microcomputer. and a voltage supply means configured to supply the microcomputer with at least one of the output voltage of the constant voltage power supply and the voltage of a backup battery having a voltage value lower than this voltage. It is a starting device for

Operation According to the above-described configuration, the present invention cancels the reset of the microcomputer after the main battery attachment signal becomes stable, and starts the microcomputer.

Embodiment FIG. 1 is a schematic diagram of an embodiment in which the microcomputer starting device of the present invention is applied to an electronic still camera.
A standby battery with a voltage lower than the voltage supplied to the microcomputer 1 through the standby battery 5 generates the synchronization signal necessary for the video signal from the original oscillation signal having a frequency four times that of the color subcarrier signal (hereinafter referred to as subcarrier). A well-known synchronizing signal generator 6 is used to generate signals from when the output voltage of the converter 4 reaches a value higher than the specified value when the main battery 2 is installed while the microcomputer 1 is not activated until the output of the synchronizing signal generator 6 becomes stable. A reset circuit that resets the time microcomputer 1; 7 is an OR gate circuit that ORs the output of the reset circuit 6 and the signal on the output line of the 0UT2 terminal of the microcomputer 1; 11.12 is a standby battery 3 connected to the vDD terminal of the microcomputer 1; A diode for configuring an OR circuit for supplying voltage or the output voltage of converter 4, R1 is ○UT1 of microcomputer 1
A resistor for pulling up the output line of the terminal to the main battery 2, R2 is a resistor for pulling down the output line of the OR gate circuit 7 to the ground, and R3 is the OU' of the icon 1.
This is a resistor for pulling down the output line of the r2 terminal to ground.

The reason why the same numbers as the conventional device are given here is that the operation is the same, so the explanation will be omitted.

FIG. 2 is an operating waveform diagram of the microcomputer startup device configured as described above, where a is the output voltage waveform of the converter 4,
b is a signal with twice the frequency of the subcarrier output from the synchronization signal generator (hereinafter referred to as the "gc times signal"), which is input to the 08C1 terminal of the microcomputer 1 and used as a high-speed clock.C is the signal from the reset circuit 6. d is the output from the 0UT2 terminal of the microcomputer 1 and is a signal input to the other input terminal of the OR gate circuit 7. e is the output of the OR gate 7. The reset signal f that starts microcomputer 1 is generated inside microcomputer 1, and the clock used internally is set to high speed/
Clock switching signal to switch to low speed, q is microcontroller 1
This is a converter control signal that is output from the oUT1 terminal of the converter 4 and controls the on/off of the converter 4.

The operation of the microcomputer startup device of this embodiment configured as described above will be described below.

If you install the main battery 2 while the microcomputer 1 is completely energized, the status of the output port is not determined because the microcomputer 1 is still energized, but the output line of the output port 0UT1 is OK! The resistor R1, which is pulled up to the resistor R1, becomes "H" level (FIG. 2q), and the converter 4 starts operating, and its output a gradually rises. When the output a of the converter 4 reaches a certain voltage level, the synchronizing signal generator 6 begins to operate, and although unstable, signals 2f and c begin to be output as shown in FIG. By the way, microcontroller 1 also has diode 12.
The current is applied through the ``sc'' signal, and the ``sc'' signal is also input to the 03CI terminal, which is the black reference input terminal. However, the microcontroller 1 is reset to the 03CI terminal, which is the black reference input terminal. However, the microcontroller 1 is reset at the level of the 03CI terminal, which is the 03CI terminal. The microcomputer 1 remains in the reset state due to the output signal C of the circuit 6. Therefore, the output port of microcomputer 1 changes from an unstable state immediately after power supply starts to a high impedance state, but OUT 1
The output line of is maintained at the "H" level due to the pull-a-puffer resistor R1, and the converter 4 continues to operate. Next, the time T1 during which the output & of the converter 4 reaches a value higher than the specified value and the 2f8c signal, which is the output of the synchronizing signal generator 5, becomes sufficiently stable.
When the time period elapses, the output C of the reset circuit 6 should release the reset and reset of the microcomputer 1 (becomes H” level.Microcomputer 1
When the reset is released, the initial escape program is executed to operate and maintain the converter 4 (1' 0
An "H" level signal is output from the UT1 terminal, and initial settings of each circuit and mechanism etc. are performed through this circuit. Next, a standby battery 3 with a voltage value lower than the voltage supplied to the microcomputer 1 is installed, and the low-frequency ice crystal oscillator 13 stabilizes the oscillation of the low-speed clock generated inside the microcomputer 1. The output of the 0UT2 terminal (FIG. 2 d) is set to the "H" level, and the reset terminal of the microcomputer 1 is kept at the "H" level through the OR gate circuit 7, thereby prohibiting the reset circuit 6 from resetting the microcomputer 1.

This is because after the microcomputer 1 starts up as described above, as long as the standby battery 3 is installed, replacing the main battery 2 will reset the microcomputer 1 and erase necessary internal data such as calendar and clock data. 6 for prevention. After that, the microcomputer 1 switches the internal clock to a low-speed clock as shown in Figure 2 f, and outputs the OUT
The output q of the first terminal is set to "L" level, the converter 4 is turned off, and the system enters a standby state in a low power consumption mode. In the low power consumption mode, current flows through the resistors R1 to R3, but since these resistors have high resistance, their values can be ignored.

Next, when operating the system from this standby state, the converter 4 is turned on through the 0UT1 terminal of the microcomputer 1. When the converter 4 is turned on (FIG. 2q), the synchronizing signal generator 6 to 2 is activated as shown in FIG.
After the fsC signal is generated and stabilized, the microcomputer 1 switches the clock to the high speed side and immediately starts operating the system. At this time, the reset signal e remains at "H" and the microcomputer 1 is not reset again. FIG. 3 is a diagram showing the operation interval of the electronic still camera of this embodiment, where the system operation time, that is, the photographing time T. is short, this shooting time T
. The non-photographing time, that is, the standby time T,o is generally very long. For this reason, it is essential for the system to reduce the lifespan of the standby battery 3, that is, to reduce the power consumption during standby.

Even if the standby battery 3 at startup of the microcomputer 1 is installed first, if the main battery 3 is not installed, the reset circuit 6 causes the microcomputer 1 to switch to the main battery 2.
It will remain reset until it is installed. Now, the microcomputer 1 is started by installing the main battery 2, but there is also a method of starting the microcomputer 1 by using the standby battery 3. With this method, the voltage of the standby battery is low, so it can only be started with a low-speed clock. By the way, this low-speed clock takes time to stabilize after power is applied, for example, the frequency is 30K.
At around Hz, it takes 1 to 1.5 (sec), and microcontroller 1
There is a problem in that the initial setting of the descendant circuit after energization is delayed. Therefore, as mentioned above, a high-speed clock is required to start up the microcomputer 1.

As described above, according to this embodiment, by forcibly turning on the microcomputer startup converter 4, energizing the microcomputer 1, and using a high-speed clock, initial settings can be performed in a short time. In power consumption mode, not only the clock is switched to a lower speed, but also the standby battery 3
This makes it possible to lower the voltage supplied to the microcontroller, resulting in lower power consumption compared to conventional devices. In addition, by turning on the converter 4 at startup, the clock of an external oscillator, such as a synchronization signal generator that generates various synchronization signals essential to the system, can be used as a high-speed clock. There is no need for a lock oscillation element, which reduces the cost of the circuit, and at the same time, since there is only one system of high-frequency clocks, there is no noise caused by beat signals as in the conventional case. Furthermore, since the voltage supplied to each circuit and the voltage during operation of the microcomputer are both supplied from the converter during operation and are the same, the reception of signals between the microcomputer and each circuit is done using level conversion, etc., as described in the conventional example. No interface is required, allowing for smaller circuits and lower costs. In this embodiment, during standby, microcomputer 1
However, if the output port of microcomputer 1 connected to each circuit is set to "L" level, the components due to the voltage difference between microcomputer 1 and each circuit will be energized. Since no destruction occurs, there is no practical problem.

As described in detail, the present invention can provide a microcomputer startup device that consumes less power than conventional devices and is even more cost-effective, and has great practical effects. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a microcomputer startup device in an embodiment of the present invention, FIG. 2 is an operation waveform diagram of the embodiment, and FIG. 3 is an explanatory diagram of the operation interval of the system in this embodiment. FIG. 4 is a schematic diagram of a conventional microcomputer startup device. 1...Microcomputer, 2.1. a...
...Battery, 4...DC-DC converter,
6... Synchronous signal generator, 6... Reset circuit, 13... Crystal oscillator. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Figure 4 Procedural Amendment Document September 20, 1988 1 Display of Case 1988 Patent Application No. 304231, Title of Invention Microcomputer Starting Device 3 Amendment to Personnel A'1 and Opening of Case Special permission
Colonel: 1006 Oaza Kadoma, Kadoma City, Osaka Name (582) Representative of Matsushita Electric Industrial Co., Ltd.
Akio Tanii 4 Agent 571 Address 1006 Oaza Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 5 Subject of amendment 6 Contents of amendment (1) Page 11, line 6 to page 11 of the specification In line 8, “
If you install the main battery with no power at all, it will be energized.'' will be corrected to ``If you install the main battery 2 with no power at all, the microcontroller 1 will not be energized yet.'' I will. (2) Change the time To J on page 14, line 8 to “Time Ts
” will be corrected. (3) "Main battery 3" on page 14, line 12 will be corrected to "main battery 2." °(4) In the same page, page 14, line 17, "There are other ways. But in this way" will be amended to "There are other ways, but in this way." (5) Figure 2 of the drawing will be corrected as shown in the attached sheet.

Claims (2)

[Claims] (1) A constant voltage power supply that receives power from a battery and supplies stable voltage to each circuit, whose on/off operation is controlled by the output port of a microcomputer, and a constant voltage power supply that supplies voltage from this constant voltage power supply. means for generating a clock signal that can be used as a high-speed clock for the microcomputer in response to the above-mentioned microcomputer; and a time period at least until the output of the clock signal becomes stable after the set voltage power supply operates and reaches a predetermined voltage when the microcomputer is started. reset signal generating means for generating a signal to reset the microcomputer; means for operating the constant voltage power supply regardless of the output of the output port when resetting the microcomputer; 1. A starting device for a microcomputer, comprising: voltage supply means configured to supply an output voltage. (2) After the microcomputer starts up and the operation of the constant voltage power supply is turned off by the microcomputer,
Activation of the microcomputer according to claim 1, further comprising means for supplying the microcomputer with a voltage of a standby battery having a voltage value lower than the output voltage of the constant voltage power supply to place the microcomputer in a standby state. Device.