JPH0338985A - Method of access to memory card for picture data recording - Google Patents

Abstract

PURPOSE:To reduce the number of address lines between the main body of a camera or the main body of a reproducing machine and a memory card and to improve reliability by accessing the memory card for each block to be determined by high-order bits when the memory card for picture data recording is accessed. CONSTITUTION:The address of a memory in the memory card is divided into the high-order bits and low-order bits. Then, an address counter 11 is provided as a high-order bit address means to take in charge of the high-order 16 bits and an address counter 12 is provided as a low-order bit address means to take in charge of low-order 8 bits. These address counters are connected to the address bus of a memory 13. When the memory is accessed, only the high- order bits of the address are designated from an external part and simultaneously with this designation, the low-order bit address means is reset to an initial value. Then, the access is started and afterwards, the address is successively counted up or down by the counter 12 and sequentially accessed. Then, picture data are written or read. Thus, the number of the address lines can be reduced and the reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a method of accessing a memory card for recording image data.

<Prior art> Some electronic still cameras convert image signals from an image sensor such as a CCD into A/D and record them on a memory card that is removably attached to the camera body. Publication No. 63-72283.

(See Japanese Patent Application Laid-open No. 10784/1984).

This memory card is usually a business card-sized board with SRAM, D
A memory chip such as RAM, EPROM or EEPROM is incorporated and covered with a plastic sheet, and a connector is formed at the end.

<Problems to be Solved by the Invention> By the way, when accessing such a memory card from the camera body or the playback device body, the number of address bits increases in accordance with the memory capacity, so the address line becomes This increases the number of connector pins, which increases the chances of poor contact, etc.
There are problems with reliability.

In view of these conventional problems, the present invention focuses on the special feature that the data to be recorded is image data, thereby making it possible to reduce the number of address lines (number of pins) and improve reliability. , an object of the present invention is to provide a method of accessing a memory card for recording image data.

<Means for Solving the Problems> Therefore, the present invention provides the following first and second methods.

The first method is to divide the memory address in the memory card for recording image data into upper bits and lower bits, and when accessing the memory, only the upper bits of the address are specified externally. The access is started by setting the bit address means and at the same time resetting the lower bit address means to the initial value;
Image data is written or read by sequentially accessing the address by sequentially increasing or decreasing the address by the address means.

The second method is to divide the memory address in the memory card for recording image data into upper bits and lower focus bits, and store the upper bits of each memory address for each screen worth of image data in the memory card. A management memory is provided, and when accessing the memory, the management memory is accessed externally, the upper bits of the address on the memory are obtained, the upper bit address means is set, and at the same time, the lower bits are set. The address means is reset to an initial value to start accessing the memory, and then the address is sequentially raised or lowered by the lower bit address means for sequential access to write or read image data.

Since the image data is continuous within the range equivalent to one screen and there is no need to read it out from the middle, the first method manages each block determined by the upper bits, and the second method manages the data block by block. Writing or reading is performed for each block determined by the upper bits through the memory, thereby reducing the number of address lines (number of pins) between the camera body or playback device body and the memory card.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 3 shows an example of an electronic still camera system. This system operates under the control of a control block 1 and a clock generation circuit 2, and an optical image of a subject is provided to an image pickup device 4 such as a CCD through an optical system 3. and the image sensor drive circuit 5
A photoelectrically converted analog image signal is transferred from the image sensor 4 by a transfer pulse from the image sensor 4 .

The analog image signal from the image sensor 4 is subjected to signal processing in an analog processing circuit 6, and then converted to digital image data in an A/D converter 7.

The digital image data from the A/D converter 7 is
After the signal is processed by the digital processing circuit 8, it is written to the memory card 10, which is detachably attached to the camera body, via the interface 9. Further, the image data written to the memory card 10 is read into the camera body side as necessary.

At the time of reproduction, the memory card 10 is attached to a reproduction machine, and the image data is read and reproduced by the reproduction machine.

The present invention provides a method for accessing such a memory card, and hereinafter, the memory addresses of the memory card are assumed to be 0OOOOOH to FFFFFFH (H represents a hexadecimal number).

First, an example corresponding to the first method will be described.

In the first method, the memory address in the memory card is divided into upper bits and lower bits.
The address is divided into 6 bits and the lower 8 bits, and when accessing the memory, only the upper 16 bits of the address are specified from outside, and a block of 256 words (as shown in Figure 2) is created.
(OOH-FFH).

In the example shown in FIG. 1, the memory card is provided with an address counter 11 that handles the upper 16 bits as an upper bit address means, and an address counter 12 that handles the lower 8 bits as a lower bit address means. It is connected to the address bus of the memory 13. .

When accessing the memory, a 16-bit address is sent from the camera side via the address bus, and is preset in the address counter 11 by a preset signal. At the same time, the address counter 12 is reset,
The initial value is set to OOH.

As a result, the 16-bit address from the camera side becomes 1
If it is 00OH, access to address 100000H of memory 13 is started. That is, depending on the control signal (R/W signal, C5 signal, etc.), data on the data bus is written to this address in the memory 13, or data at this address is read out through the data bus.

Thereafter, the address counter 12 is counted up one after another by the clock signal, and the next address is accessed.

When the address counter 12 goes from FFH to OOH, a carry signal is generated, which makes the clock signal for the address counter 11 valid, and the address counter 1
The count is incremented by 1, and the next block is successively accessed.

This allows image data to be written and read.

The examples in FIGS. 4 and 5(a) and 5(b) show a case where image records in a memory card are organized by applying the access method shown in FIG. 1.

Although image data is stored in the memory of the memory card in the order in which it was taken, specific image data may be erased by the erase function of the camera or playback device after the image is taken. In such case,
For example, if you delete the fifth image after taking six pictures, an empty area will be created in the recorded area of the memory, so as shown in Figure 6, the image data in the area of the sixth picture will be deleted from the fifth picture. It is desirable to move it to an empty area and fill up the empty area. This example meets this demand.

First, the upper 16 bits (for example, 600
0H) is sent, and the address counter 11 is preset by the preset signal.

Next, the copy destination (D) is 5 through the address bus.
The upper 16 bits (for example, 5000H) of the start address of the th area are sent and preset in the address counter 11' by the preset signal . At the same time, the address counter 12 is reset by the reset signal and set to the initial value 00).

Here, in response to the S/D switching signal, S/D switching switch 1
4 is switched, first it is switched to the S side, and data is read.

That is, access is started to the address 600000H of the memory 13, and the control signal (R/
W signal, etc.), the data at this address is read out and latched into the latch circuit 15.

Next, the S/D changeover switch 14 is switched to the D side, and data is written.

That is, access is started to the address of 500000H in the memory 13, for example, and the control signal (R/
W signal, etc.), the latch circuit l1 is
The data on 115 is written.

Thereafter, the address counter 12 is counted up one after another by the clock signal, and with the operation of the S/D changeover switch 14, access is made to each next address, and image data is successively copied.

When address counter 12 goes from FFH to OOH, it generates a carry signal, which causes address counter 11 .
The clock signal for 11'' becomes valid, the address counter 11.11° counts up, the next block is accessed successively, and the image data is further copied one after another.

This allows the image data to be packed.

The example of FIGS. 7 and 8 uses the address counter 11.11'' as the two upper bit address means of the example of FIG.
is changed to an address latch of 16.16°.

According to this, the burden on hardware is reduced.

However, for each block (256 words) copied, the top 1
It is necessary to preset 6 bits, which increases the software burden.

Further, when accessing a memory card for recording image data, it is preferable to place management data as illustrated in FIG. 9 in a specific area in the image memory.

Here, if N sheets are to be recorded, all data from the Nth sheet onwards is set to "O".

Therefore, by performing sequential access from OOH,
When a word L″O++ is detected, the previous word is the last recorded address.
The remaining capacity can be calculated from the contents of OH and OIH.

Also, when a memory card is inserted into the camera, this area is first read out and placed in the camera's memory.

While the camera's power switch is on,
It is preferable to rewrite data only in the memory on the camera side, and when the power switch is turned off, transfer this data to the memory card side and then turn off the power. In this case, it is necessary to prevent the memory card from being forcibly pulled out suddenly.

Alternatively, during periods of high-speed operation such as high-speed continuous shooting, rewrite only the data in the camera's memory but do not rewrite the memory card, and immediately after the high-speed operation ends and you have time to spare. It is a good idea to rewrite the memory card as well. This makes it safe even if the card is removed at any time.

Next, an example corresponding to the second method will be described.

Referring to FIG. 10, in the second method, image data is sequentially stored in the memory 13 in the memory card, and each image data corresponding to one screen is stored in the memory card at an address (for example, the final address) on the memory 13. ) is provided with a management memory 17 that stores the upper bits of the data. Then, access is made via this management memory 17. Figure 11 shows an example of the contents of the management memory.
It is 16 bits. Furthermore, FFH of the management memory 17
Addresses have a counter function.

First, the procedure for calculating the remaining capacity of the image memory will be explained.

(1) Control signals ■, ■ R/W=R (read/
When the write signal is read, 0E=DIS (output enable signal non-output state), OOH is output from the camera side to the data bus, and a pulse is output to the clock (2).

(2) Set the data bus to the input state and set the control signal to 0E=E (output enable signal output state). As a result, the contents (16 bits) of the address OOH are output from the management memory 17.

(3) While switching the select switch 18 using the select signal, read the upper 8 bits and lower 8 bits to the camera side through the data bus. This allows the capacity of the memory card, which is the content of the address OOH, to be known.

(4) Next, control signals ■ and ■ are R/W=R,0
Set E=DrS, output FFH from the camera side to the data bus, and output a pulse to the clock.

(5) Put the data bus into the manual state and control signal■
Let 0E=E. As a result, the contents of the address FFH are output from the management memory 17, and the select switch 1
Only the upper 8 bits (or 8 bits) are taken out via 8.

The "address of the last recorded image" stored in address FFH is an address (8 bits) in the management memory 17, and is 06H if up to the 6th image has been photographed.

Here, since the management memory 17 is l words - 16 bits, this data is written in either the upper 8 bits, the lower 8 bits, or both.

(6) Control signals ■, ■ R/W = R, 0E
=DIS, the data extracted in (5) is sent to the management memory 17 via the data bus, and a pulse is output to the clock.

(7) Put the data bus in the input state and set the control signal to 0E=E. As a result, the contents (16 bits) of address 06H, for example, are output from the management memory 17.

(8) While switching the select switch 18 using the select signal, read the upper 8 bits and lower 8 bits to the camera side through the data bus. This makes it possible to know the final address of the sixth image, which is the content of address 06H. In this example, this is the final address of the final recorded image.

(9) Image memory 13 from data of (3) and (8)
Calculate the remaining capacity of.

Next, the procedure for additional recording will be explained.

(1) Control signals ■, ■ R/W = R, 0E
=DIS, output FFH from the camera side to the data bus, and output a pulse to the clock.

(2) Put the data bus into the manual state and control signal■
Let 0E=E. As a result, the contents of the address FFH are transferred from the management memory 17 (16 bits, for example, if up to the 6th disc has been recorded, the upper 8 bits).

The lower 8 bits (or both are 06H) are output.

(3) Extract only the upper 8 bits (or lower 8 bits) from the output via the select switch 18.

As a result, for example, 06H is read.

(4) Set the control signal ■ to 0E=DIS, send the data read in the above (3) to the management memory 17 via the data bus, and output a pulse to the clock.

(5) Bring the data bus to the input state and set the control signal to 0E=E. As a result, the upper 16 bits (for example, 5555H) of the final address of the last recorded image, for example, the sixth image, are output from the management memory 17.

(6) Output pulses from the camera side to the set.

As a result, the address counter 11 is preset to, for example, 5555H, and the address counter 12 is preset to FFH. Then, output a pulse to the clock ■,
The address counter 12 is incremented by 1. As a result, the address counter 11 is set to 5556H, and the address counter 12 is set to OOH.

(7) Set the control signal ■ to 0E=DIS.

(8) Output image data from the camera side to the data bus,
Outputs a pulse to clock ■. This is repeated for the number of image data, thereby writing the image data.

(9) Output [data read in (3) above]=07H, for example, to the data bus. Then, the control signal is set to W/R=W, and a pulse is output to the clock.

00) A pulse is manually applied at -2 of the clock to amplify the contents of the FFH address of the management memory 17 by one count.

Next, erasure will be explained.

For example, when deleting the fifth image, first A=(05
Contents of address H) +1. B= (Contents of address 04H)+1
The contents of the image memory at address A are moved to address B.

Then, while incrementing A and B by one, the contents of the image memory at address A are transferred to address B.

This is repeated until the value of A becomes the same as the value of the content of 06H, and the value of B at this time is entered into 05H.

Next, repeat until the value of A becomes the same as the content of 07H, and then put the value of B at this time into 06H.

Then, these steps are performed on all recorded images.

Incidentally, in the above explanation, all counters have been explained using increment operations, but needless to say, they may also perform decrement operations.

<Effects of the Invention> As explained above, according to the present invention, when accessing a memory card for recording image data, data is accessed for each block determined by the upper bits, or for each block determined by the upper bits via the management memory. , the number of address lines (number of pins) between the camera body or playback device body and the memory card can be reduced, and reliability can be improved.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment corresponding to the first method of the present invention, Fig. 2 is a schematic diagram of an image memory, Fig. 3 is a system diagram of an electronic still camera, and Fig. 4 is a diagram showing another embodiment. Figure 5
Figures (a) and (b) are timing diagrams for the example in Figure 4, Figure 6 is a diagram showing how data is packed, Figure 7 is a diagram showing another embodiment, and Figure 8 is a diagram for the example in Figure 7. FIG. 9 is a schematic diagram of the management data area, FIG. 10 is a diagram showing an embodiment corresponding to the second method, and FIG. 11 is a schematic diagram of the management memory.

Claims (2)

[Claims] (1) Divide the memory address in the memory card for recording image data into upper bits and lower bits, and when accessing the memory, specify only the upper bits of the address from the outside and set the upper bit address means, At the same time, the lower bit address means is reset to the initial value to start access, and then the address is sequentially raised or lowered by the lower bit address means for sequential access to write or read image data. A method for accessing a memory card for recording image data, characterized by: (2) Management in which memory addresses in a memory card for recording image data are divided into upper bits and lower bits, and the upper bits of each memory address are stored in the memory card for each image data equivalent to one screen. When accessing the memory, the management memory is accessed externally, the upper bits of the address on the memory are obtained, the upper bit address means is set, and the lower bit address means is set at the same time. Image data recording characterized by resetting to an initial value, starting access to the memory, and then sequentially increasing or decreasing the address using lower bit address means to perform sequential access to write or read image data. How to access your memory card.