JP2825002B2 - Facsimile apparatus and data transfer method thereof - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus that stores image data in a removable storage medium and a data transfer method thereof.

[Prior Art] In a conventional facsimile apparatus, when the read image data is printed on a recording sheet, the image data is directly stored in an image memory.
To improve the storage efficiency of image memory, MR or MMR
And so on, and is configured to accumulate the encoded data.

In recent years, in addition to storing in image memory,
A facsimile apparatus that transfers encoded data to a floppy disk and stores it as a file has also been proposed.

[Problem to be Solved by the Invention] However, in the above-described conventional example, when the encoded data is stored in the image memory, the size of the image memory is limited, and the maximum value of the number of data that can be stored is determined. Normally, an image memory is not an S-RAM that can be easily backed up with a battery or the like, but an inexpensive D-memory for an S-RAM.
Although a RAM is used, this D-RAM needs to be refreshed at regular intervals, which consumes a large amount of power, and it is virtually impossible to back up when the power is cut off due to a power failure or the like. Was. When a D-RAM is used as an image memory, if a large amount of data to be transmitted is to be stored, a large amount of memory must be mounted, and as a result,
There has been a problem that the cost of the memory components has increased, the product cost has increased, and it has been impossible to provide an inexpensive facsimile machine.

When the encoded data is directly stored on a floppy disk, when the data is transferred to the floppy disk, the highest priority is given to the data, and for the other data transfer, the data transfer to the floppy disk is performed. I had to do it when I wasn't. In other words, a floppy disk stores data in a magnetic material that rotates at a constant speed, and the data transfer rate from the floppy disk controller (FDC) to the floppy disk drive (FDD) must be constant. No.

For this reason, when prioritizing other processes and stopping data transfer to the floppy disk or attempting to transfer more data than a predetermined value, the floppy disk may cause an overrun error or an underrun error. Was.

For example, when the coded data is transferred to the image memory and transferred to the floppy disk at the same time, it is necessary to suspend the operation of the original reading unit and the encoder according to the data transfer status to the floppy disk. Was. In this case, as compared with a conventional facsimile apparatus that stores a transmission document in an image memory, the operation speed is slower and the usability of the user is deteriorated. The damping frequently occurs, causing a serious problem of deteriorating the image quality.

The present invention has been made in order to solve the above-described problem, and performs a process of transferring input image data to an image memory and a process of transferring image data stored in the image memory to a removable storage medium in parallel. It is an object of the present invention to provide a facsimile apparatus which can store image data in a storage medium in a short time as a whole and a data transfer method thereof.

Means for Solving the Problems To achieve the above object, the present invention relates to a facsimile apparatus for storing image data in a removable storage medium, wherein the input means inputs image data, and the input means An image memory for storing the image data input by the input unit, a first transfer unit for transferring the image data input by the input unit to the image memory, and temporarily storing the image data in the storage medium A buffer memory, a second transfer unit for transferring the image data stored in the image memory to the buffer memory, and a storage medium control unit for storing the image data stored in the buffer memory in the storage medium. The bus used for the transfer by the first and second transfer means is used in a time-division manner, so that the transfer by the first transfer means and the second And the transfer by the transfer means is executed in parallel, and the use of the bus for the transfer by the first transfer means is prioritized over the use of the bus for the transfer by the second transfer means. The transfer by the first transfer unit is performed prior to the transfer by the second transfer unit.

In order to achieve the above object, the present invention relates to a data transfer method for a facsimile apparatus for storing image data in a removable storage medium, wherein the input step includes inputting image data, A first transfer step of transferring image data to an image memory for storing the image data, and the image data stored in the image memory;
A second transfer step of temporarily transferring the image data to the storage medium to a buffer memory, and a storage medium control step of storing the image data stored in the buffer memory in the storage medium, By using a bus used for the transfer in the first and second transfer steps in a time-division manner, the transfer in the first transfer step and the transfer in the second transfer step are executed in parallel, The use of the bus for the transfer in the first transfer step is prioritized over the use of the bus for the transfer in the second transfer step, so that the transfer in the first transfer step is performed in the second transfer step. The transfer is executed prior to the transfer by

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic block diagram showing the configuration of the facsimile apparatus in the present embodiment. In the figure, reference numeral 1 denotes a document reading unit, which reads a transmission document by a photoelectric conversion element such as a CCD,
It outputs image data converted to digital signals. Reference numeral 2 denotes an encoder which converts image data read by the document reading unit 1
The data is converted to an MH (Modified Haduan) or MR (Modified Read) code, and data is compressed. Reference numeral 3 denotes a memory unit that stores various data, an image memory 4 that stores encoded image data, a system RAM 5 that stores a system state, and a ROM 6 that determines an operation of the apparatus.
And 7 is floppy disk controller (FD
Part C) controls the floppy disk device and includes the FIFO 8 according to the present embodiment inside. Reference numeral 9 denotes a floppy disk drive (FDD) for writing data to or reading data from the floppy disk medium 10 and transmitting information on the type of the floppy disk medium 10 to the FDC 7, such as the presence or absence and density of the floppy disk medium 10 to be inserted.

Reference numeral 11 denotes a decoder, which decodes data encoded by the own device or the communication partner device. Reference numeral 12 denotes an operation panel, which includes a display 13 for displaying the state of the apparatus and operation keys including ten keys and various function keys.
Reference numeral 15 denotes a sensor, which detects a state such as whether or not a document is set in the document reading unit 1. A recording unit 16 records a received image or a copy image. Reference numeral 17 denotes a modem control unit, which controls the modem 18 and the like. Reference numeral 19 denotes an NCU which switches the telephone line to the facsimile side.

Reference numeral 20 denotes a central control unit that controls the above units 1 to 19,
DMA controller 21 that controls data transfer between memories
When the image memory 4 is a D-RAM, the image memory 4 comprises an image memory control unit 22 for controlling refreshing and the like, and a main CPU 23 for controlling according to the processing procedure stored in the ROM 6.

Next, the data transfer operation of the facsimile apparatus having the above configuration will be described below with reference to FIGS.

FIG. 2 is a diagram for explaining the flow of image data of the facsimile apparatus in the present embodiment. FIG. 3 is a diagram showing control signals between the DMA controller 21 and the image memory control unit 22 shown in FIG. 2, and FIGS. 4 and 5 are timing charts showing the timing of each control signal. It is.

First, the image data 1a read by the document reading unit 1 and converted into a binary signal representing white or black is output to the encoder 2. The encoder 2 performs data compression, and the encoded image data 2a is stored in an encoded data storage area of the image memory 4 by a DMA controller 21 and an image memory control unit 22, which will be described later. Here, as shown in FIG. 3, the DMARQ1 signal is output from the encoder 2 to the DMA controller 21, and if transfer is possible, the DMACK1 signal is returned. The address Ay is output to the image memory control unit 22 to transmit the data. Start the transfer.

Then, data transfer is performed at the timing shown in FIG. At this time, the address Ay of the encoder 2 is output once, and the subsequent addresses are controlled by the address auto-increment function using the DRCK signal of the encoder 2. That is, when the address Ay indicates A _0, from the encoder 2 outputs the data D _0, the DRCK signal is input, address
Is incremented to A _1, the sequential data is output. Also, the image memory control unit 22 sends a REA
The DY signal is output, and the wait signal (T _w )
Is inserted.

Note that the DMA controller 21 ignores the DMARQ2 signal from the FDC 7 until the above-described continuous transfer (DRAM access in the high-speed page mode) is completed, and when this data transfer is completed, the image memory 4 at the timing shown in FIG. From
Data transfer to FDC7 (access in normal mode)
Perform

Next, the encoded data stored in the image memory 4 is
The data is transferred to the internal FIFO 8 and transferred to the FDD 9. Then, the data is written to the floppy medium 10 by the FDD 9.

That is, in the present embodiment, as shown in FIG. 6, the data transfer from the encoder 2 to the image memory 4 is performed by combining the image data with a predetermined word by the highest priority DMA transfer (b '). The data transfer to the FIFO 8 is performed during the idle time (a ').

FIG. 6 is a diagram showing the transfer timing of image data. Usually, the amount of image data and the data transfer speed are
It is determined by the reading speed of the document reading unit 1, the document size, the document reading density (fine mode, normal mode), etc., and is not fixed, but is a binary value indicating whether the read image data is black or white. The data 1a is transferred to the encoder 2 at a constant speed. Next, the image data 1a is encoded by the encoder 2 and transferred to the image memory 4. Note that the data amount of the encoded data changes depending on the input pattern to the encoder 2. In general, a complicated input pattern with a large number of black and white inversions has a larger encoded data amount.

Next, at the same time as the encoding is completed, the DM
If an A transfer is attempted, the bus occupancy of this DMA becomes enormous. The example shown in FIG. 6 shows a case where data is transferred at equal intervals, and “b” indicates a time during which the bus is occupied by the DMA transfer. Accordingly, when performing low-priority DMA transfer or processing each having a lower priority than DMA, the bus idle time "a"
Need to run between.

However, when the document reading speed is increased, the idle time "a" becomes very short, and it becomes impossible to execute a low-priority DMA transfer or each processing within this time. For this reason, in this embodiment, a method is used in which the DMA data transfer with the highest priority is collectively executed, idle time is collectively created, and processing with a low priority is collectively executed there.

Another way to transfer data in a batch is
One advantage is that when the image memory is a DRAM, access in the high-speed page mode becomes possible, and the data transfer time is reduced. In other words, the method of collectively transferring data with high priority, collectively creating idle time, and performing processing with low priority has great merits and is widely used.

However, as a demerit, the priority is momentarily high
The point is that the bus occupancy increases due to the DMA transfer, and the time during which the lower DMA or other processing cannot be accepted is instantaneously increased.

In particular, if the lower DMA attempts to transfer data to the FDC 7, the DMA cannot be accepted, and it becomes impossible to send data to the floppy disk 10 at a constant speed.

Therefore, in order to solve this problem, in this embodiment,
FDC7 is provided with FIFO8, and when DMA transfer with high priority is performed, DMA transfer to FDC7 lower than it, that is, even when data transfer 3a is not performed at a constant speed, FDC7 to FDC9. Is configured to be able to perform data transfer at a constant speed.

Therefore, data is stably transferred to a floppy disk device without causing an overrun error or underrun error of the floppy disk.

FIG. 7 shows the amount of data stored in the FIFO 8 and the FDC 7
As shown in the figure, the DMA request signal starts to be transmitted while the FIFO 8 is dividing the threshold level, and the DMA request signal is transmitted when the FIFO 8 is full as shown in the figure. Stop sending. The threshold level is set to a value that does not cause an overrun or underrun error on the floppy disk even when the time during which the information compression rate of encoding becomes the longest is the longest.

The amount of the FIFO 8 used and the threshold level are variable within a range that does not cause the above-described error, and when a DMA transfer lower than the DMA to the FDC 7 is performed, these are adjusted according to the timing. The value is main
It is controlled by the CPU 23.

Further, the above-described data transfer speed changes the data transfer speed depending on the type of the floppy disk 10. For example, if the floppy disk 10 is formatted in the MFM mode on a 2HD medium, the transfer speed is 500 kbps. The threshold level is selected to be half of 2HDMFM.

In this embodiment, the timing is adjusted within a range in which the floppy disk does not generate an overrun or underrun error by changing the amount of the FIFO 8 and the threshold level in accordance with the transfer speed.

That is, the amount of the FIFO 8 and the threshold level are changed according to the width of the read original. The time required to read one scanning line of a normal facsimile apparatus is determined by the system. As the document width increases, the amount of data read per line increases. Therefore, the amount of encoded data also increases, and the bus occupancy when the encoded data is transferred to the image memory also increases.

Therefore, the larger the document width, the greater the amount of FIFO8 and the threshold level, unless the floppy disk will cause an overrun or underrun error. The threshold level is changed. For example, manuscript width
In the case of A3, it is selected to be twice that of A5.

The data transfer from the image memory 4 or the FDC 7 to the recording unit 16 or the modem control unit 17 is performed by a DMA having a lower priority than the DMA transfer to the FDC 7. Therefore, the larger the amount of the FIFO 8 used and the value of the threshold level, the longer the bus occupation time during the DMA transfer becomes, and the longer the recording unit 16 cannot obtain data for a long period of time, which is not preferable in operation. .

In particular, the recording unit 16 performs an operation of receiving data for one line of a recorded image and printing the data. However, since the recording unit 16 usually has only a small-capacity buffer memory, data transfer from the image memory 3 or the FDC 7 is not possible. If not,
I have to suspend the recording operation. However, temporarily suspending the recording operation causes damping of the motor that transports the recording paper, and causes significant degradation in the quality of the recorded image.

In order to solve this problem, if a buffer memory is added, the time from the start of data transfer from the image memory 3 or the FDC 7 to the printing of an image on a recording paper becomes enormous. Is high. For example, if the user presses the key 14 in order to print the report of the communication result on the recording paper, it takes a considerable time until the communication result data stored in the image memory 3 is printed by the recording unit 16. The problem evolves into a user having to wait.

Therefore, in this embodiment, the amount of the FIFO 8 to be used and the threshold level are kept to minimum values, and the recording unit 16
The impact on the environment is minimized. Encoder 2
Can perform several types of coding such as MR and MH.The coding is performed according to the coding method selected by the partner receiver or the user of the own device, and the amount of the FIFO 8 and the threshold are determined according to the coding. Level is decided.

Further, in this embodiment, the data encoded by the encoder 2 is transferred to the image memory 4. However, as shown in FIG. 8, the data may be transferred directly from the transfer buffer 2 'to the memory 4. In this case, the data stored in the image memory 4 can be displayed or recorded as it is, as compared with the method of decoding and displaying or recording the read and encoded data, so that the processing time is shortened and suitable for real-time display and the like. I have. Further, the hardware configuration is simple, and an inexpensive facsimile apparatus can be provided.

The transfer buffer 2 'shown in FIG. 8 adjusts the timing when the image data is transferred to the image memory 4, and the flow of image data is the same as in this embodiment, as shown in FIG. is there.

As described above, according to the present embodiment, the following effects can be obtained.

(1) Simultaneously storing the encoded data in the image memory and transferring and storing the data on a floppy disk, the image memory was successfully reduced, the production cost of the device was reduced, and the facsimile machine was inexpensive. Can be provided to the user.

At the same time, the time required for the encoded data to be transferred to the floppy disk drive was shortened, enabling high-speed operation of the apparatus.

(2) The highest priority is given to the DMA transfer of the encoded image data to the image memory, so that there is no need to temporarily stop reading and encoding the transmission original due to the influence of other DMA processing. This makes it possible to operate the paper feeding of the transmission original at a low speed, and minimizes the damping of the motor for feeding the paper of the transmission original. As a result, the accuracy of image reading can be improved.

(3) By providing the FDC7 with the FIFO8, it is possible to transfer the data from the FDC7 to the FDD9 at a low speed even when the encoded data is DMA-transferred to the image memory, and to guarantee the write operation to the FDD9. Become.

(4) By varying the amount of FIFO 8 and the threshold level, fine timing control according to the state of the system becomes possible, and stable operation of the apparatus can be guaranteed.

(5) The amount of FIFO 8 and the threshold level can be adjusted even if an image signal whose encoding information compression rate is the lowest is input to the encoder and the time during which lower-order DMA processing cannot be accepted is the longest. Since the floppy disk can be set so as not to cause an overrun or underrun error, the write operation of the FDD 9 can be guaranteed even if any image is input.

(6) By changing the amount of the FIFO 8 and the threshold level according to the type of floppy disk, it is possible to construct a system corresponding to diversified floppy disks.

(7) By changing the amount of FIFO8 and the threshold level according to the document size, it is possible to select the necessary minimum amount of FIFO and the threshold level, thereby minimizing the effect on the lower DMA. Can be.

(8) By changing the amount of FIFO 8 and the threshold level according to the encoding method, it is possible to select the necessary minimum amount and threshold level and minimize the influence on the lower DMA. Can be.

[Effects of the Invention] As described above, according to the present invention, first, the transfer of image data from the input unit to the image memory is preferentially executed, so that there is no data to transfer in the image memory. By adjusting the variation in the transfer of image data from the image memory to the storage medium in the buffer memory, underflow or overflow of the image data may occur even when two transfer processes are apparently executed in parallel. The image data can be appropriately stored in the storage medium without performing.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing the configuration of a facsimile apparatus according to the present embodiment, FIG. 2 is a diagram for explaining the flow of image data in the present embodiment, FIG. 3 is a diagram showing the detailed configuration of FIG. 4 and 5 are timing charts showing the timing of each control signal shown in FIG. 3, FIG. 6 is a diagram showing a transfer state of image data in this embodiment, and FIG. 7 is a timing chart in this embodiment. FIG. 8 is a diagram showing a relationship between a FIFO and a DMA request, FIG. 8 is a diagram showing a modification of the facsimile apparatus in the present embodiment, and FIG. 9 is a view showing a flow of image data in the apparatus shown in FIG. In the figure, 1... Original reading unit, 2... Encoder, 3.
…… Image memory, 7… FDC, 8… FIFO, 9… FDD,
21 ... DMA controller, 22 ... Image memory controller.

Claims (8)

(57) [Claims] 1. A facsimile apparatus for storing image data in a removable storage medium, comprising: input means for inputting image data; an image memory for storing image data input by the input means; A first transfer unit that transfers the image data input by the input unit to an image memory; a buffer memory that temporarily stores the image data to the storage medium; and an image data that is stored in the image memory. A second transfer unit that transfers the image data stored in the buffer memory to the storage medium; and a second transfer unit that transfers the image data stored in the buffer memory to the storage medium. The transfer by the first transfer means and the transfer by the second transfer means are executed in parallel by using the bus which is The use of the bus for the transfer by the first transfer means,
A facsimile machine wherein the transfer by the first transfer means is performed prior to the transfer by the second transfer means by giving priority to the use of a bus for transfer by the second transfer means. apparatus. 2. The facsimile apparatus according to claim 1, wherein said storage medium is a floppy disk. 3. The transfer by the first transfer means and the transfer by the second transfer means are transfers by direct memory access (DMA) processing, and the transfer by the first transfer means is performed by the input means. A high-speed DMA process that preferentially uses a bus used for data transfer between the image memory and the buffer memory, and the transfer by the second transfer unit performs data transfer when the bus is free. 2. The facsimile apparatus according to claim 1, wherein the normal DMA processing is performed. 4. The facsimile apparatus according to claim 1, wherein said buffer memory is a first-in first-out (FIFO) memory. 5. A data transfer method for a facsimile apparatus for storing image data in a removable storage medium, comprising: an input step of inputting image data; and storing the image data input in the input step. A first transfer step of transferring the image data stored in the image memory to a buffer memory that temporarily stores the image data in the storage medium. And a storage medium control step of storing the image data stored in the buffer memory in the storage medium, by using a bus used for transfer in the first and second transfer steps in a time-division manner. Causing the transfer in the first transfer step and the transfer in the second transfer step to be performed in parallel, and using a bus for the transfer in the first transfer step;
A facsimile machine wherein the transfer in the first transfer step is executed prior to the transfer in the second transfer step by giving priority to the use of a bus for transfer in the second transfer step. Device data transfer method. 6. The data transfer method for a facsimile apparatus according to claim 5, wherein said storage medium is a floppy disk. 7. The transfer in the first transfer step and the transfer in the second transfer step are transfer by direct memory access (DMA) processing, and the transfer in the first transfer step is performed by the input step. A high-speed DMA process in which a bus used for data transfer between the image memory and the buffer memory is preferentially used, and the transfer in the second transfer step performs data transfer when the bus is free. 6. The data transfer method for a facsimile apparatus according to claim 5, wherein the normal DMA processing is performed. 8. The data transfer method for a facsimile apparatus according to claim 5, wherein said buffer memory is a first-in first-out (FIFO) memory.