JPS63279343A - Detecting device for connection of memory unit - Google Patents

Abstract

PURPOSE:To prevent the breakage of data as well as the runaway of a program even though a card is mistakenly inserted in or taken out of a card reader, by writing the data into a specific number of the card to confirm the presence or absence of the card and also checking periodically the data to set an entire system under a stand-by state if the data has a change from its initial state. CONSTITUTION:When the pulses are periodically supplied to a CPU 4 from a timer 9, the CPU 4 compares the data read out of a memory card 1 with the latched contents of a latch circuit 5. In this case, both contents shows 'presence of card' as long as the card 1 is kept inserted. When the card 1 is taken out of a card connector 3 by some reason, the contents of the circuit 5 show 'presence of card' with the contents read out of the CPU 4 showing 'absence of data' respectively. Then the CPU 4 is set under a stand-by state. Thus it is possible to prevent the breakage of data as well as the runaway of a program.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a memory unit connection device, and in particular, the present invention relates to a memory unit connection device, and in particular, it is connected to a terminal device in a freely insertable and removable manner, and periodically checks the connection state of a data file card that is read or written. detect,
This relates to a memory unit connection detection device that maintains the entire system as necessary.

[Prior art]

Memory cards have traditionally been often used as data files, and are connected to terminal devices to read and write data. By the way, this memory card is removably connected to a terminal device, and can be inserted or removed even while reading or writing is in progress.

[Problem that the invention seeks to solve]

Since the memory card can be inserted into and removed from the terminal device as described above, if the memory card is accidentally removed from the terminal device while reading or writing, the data operation on the memory card may end prematurely. becomes. Therefore, if a subsequent program is executed in such a state, data may be destroyed or the program may run out of control.

The present invention has been devised in view of the above-mentioned circumstances and to eliminate the problem, and is intended to solve the problem that a memory card is accidentally inserted or removed while the memory card is being read or written. The present invention also aims to provide a connection detection device that can prevent data destruction and program runaway.

Means for Solving Problem C] In order to achieve the above object, the present invention provides a memory unit connecting device in which a data file card is removably connected to a terminal device and reads or writes data. A control means is provided to write data to confirm the presence or absence of a card at a specific address, and to periodically check this data and, if there is a change from the initial state, stop other processing until the initial state is matched. Configured.

[Effect]

According to the configuration of the present invention, the control means periodically checks the data written on the card to confirm the presence or absence of the card, and when there is a change from the initial state, the entire system is put into a standby state.

〔Example〕

The configuration of the present invention will be explained based on an embodiment shown in the drawings.

Fig. 1 is a circuit diagram showing the overall configuration of the memory unit connection detection device, Fig. 2 is an explanatory diagram showing the connection relationship between the memory card and the card connector, and Fig. 3 shows the procedure for detecting the insertion/removal status of the memory card. It is a flowchart.

The memory card 1 has a plurality of connection pins 1a arranged in a row on its edge. This memory card 1 is a terminal device 2 which will be described later.
is inserted into the card connector 3 and connected. That is, the card connector 3 has a plurality of connection pins 3a arranged in a row on the edge, and when the memory card 1 is inserted into the card connector 3, the connection pins 1a and 3a are connected to each other in correspondence. . Connection pin la and connection pin 4a have a power pin (vCC) and a ground pin (GND) at both ends, respectively.
will be provided. Furthermore, a data IC indicating "card present" is written in a specific address 1b of the memory card 1. Therefore, by checking the "card present" data IC at address 1b of memory card 1, it is possible to confirm whether or not memory card 1 is connected to terminal device 2.

The terminal device 2 to which the memory card 1 is connected has various functions such as reading data from the memory card 1 and writing data from the memory card 1. This terminal device 2 includes a card connector 3 to which a memory card l can be inserted and removed, and a CP that controls the overall operation of the terminal device 2.
A latch circuit that is interposed between U4, the card connector 3, and the CPU 4, and temporarily holds a signal for confirming whether or not the memory card 1 is connected to the card connector 3, that is, the insertion/extraction state. 5, RAM 6 for storing data, and RO where necessary programs are stored.
It is composed of an M7 and a human blade device 8. Further, 9 is a timer, and this timer 9 outputs a signal instructing to detect whether or not the memory card 1 is connected to the card connector 3 to the CPU 4 at regular intervals.

Between the CPU 4 and the card connector 3, the CPU 4
A data bus or the like for exchanging data between the card connector 3 and the card connector 3 is provided. Also, card connector 3
The signal output when the memory card 1 is inserted or removed is held in the latch circuit 5 and simultaneously transmitted to the CPU 4.

Next, the operation of the connection detection device having the above configuration will be explained.

When the CPU 4 receives a pulse from the timer p, the CPU 4 reads out the data 1c from the memory card 1, and the data 1c from the memory card 1 is latched into the child circuit 5. Next, timer 9 is sent to CPU 4.
When a pulse signal is input periodically from CP to
U4 inputs the data read from the memory card 1 and the lunch contents of the latch circuit 5, and compares the two. In this comparison, when memory card 1 is not inserted, both contents are "no card", and conversely, when memory card 1 is inserted, both contents are "no card".
Card included.” If the memory card l inserted into the card connector 3 is removed for some reason, the contents of the latch circuit 5 will be "Card present J, CPU4
The content read by CPU 4 is "no data", and conversely, when memory card 1 is inserted into card connector 3, the content of launch circuit 5 is "no data J", and the data read by CPU 4 is "card present". . Then, as a result of this comparison, if the signal state from the memory card 1 changes from "card present" to "no data" or from "no data" to "card present", the CPU 4 goes into standby state. In other words, like a release terminal, the program execution is stopped while the process being executed is maintained.

In this way, it is possible to detect the insertion/removal status of the memory card 1 in the terminal device 2, and when there is a change in the data from the memory card 1, the CPU 4 enters the standby state, thereby preventing data destruction or program corruption. Accidents such as reckless driving can be prevented.

The procedure for detecting insertion and removal of the memory card 1 described above is shown in FIG.
), (B) will be explained based on the flowcharts. Third
Figure (A) shows the main routine in CPU4,
First, the insertion/removal state of the memory card 1, that is, the initial state, is detected (5TEP■), and then an interrupt is received (STEP■).
EP■) and performs the necessary processing in the terminal device 2 (ST
EP■), return to 5TEP■ at appropriate intervals and check again whether the memory card I is inserted or removed (STEP■). 5TEP
In step (2), the subroutine shown in FIG. 3(B) is executed. In the subroutine, first check the content of the data from memory card 1 ("card present" or "no data") (5TEP■), and compare the result with the initial state of the data checked last time (STEP■).
. If there is a change from the initial state at 5TEP■, the CPU 5 is held in the standby state.

If there is no change in the data after 5TEP■, try again.
The process returns to the main routine of FIG. 3(A), continues the necessary processing, and repeats the above procedure.

It goes without saying that the memory unit connection detection device of the present invention can be realized by a hardware configuration or by software.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the card insertion/removal status can be confirmed by checking the data written to a specific address of the card, and if there is a change from the initial status, the entire system can be checked. Since the standby state is established, even if a card is accidentally inserted or removed during reading or writing, data destruction and program runaway can be prevented, and the entire system can be maintained.

[Brief explanation of the drawing]

The drawings show an embodiment of the memory unit connection detection device according to the present invention, FIG. 1 is a circuit diagram showing the overall configuration, FIG. 2 is an explanatory diagram showing the connection relationship between the memory card and the card connector, and FIG. 3 is a flowchart showing a procedure for detecting insertion/removal status of a memory card. (Brief explanation of the drawing showing the main parts) 1...Memory card 1a...Connection pin 1b...Specific address

Claims (1)

[Claims] A data file card is removably connected to a terminal device, and in a memory unit connection device that reads or writes data, data is written to a specific address of the card to confirm the presence or absence of the card, and this data is periodically transmitted. A memory unit connection detection device characterized in that it is provided with a control means that automatically checks the initial state and puts the entire system into a standby state when there is a change from an initial state.