JP2018085662A - Electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To tune phase shift caused by a temperature change between a clock of a host device and data from an external device within a limited time.SOLUTION: After starting electronic equipment, when an external device is connected to an external device first, all phase patterns that can be acquired are acquired and tuned, and the temperature of the external device is acquired at predetermined time intervals when an operation to generate data recording to the external device is performed, and phase patterns before and after a predetermined phase are acquired as many as possible within a pause time period in which recording to the external device is not performed last time, and a latch phase is selected from among the phase patterns when the temperature change after a latch phase has been corrected last time becomes equal to or more than a threshold value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic device.

  In recent years, the amount of data handled by digital electronic devices has been increasing, and accordingly, further speeding-up of data communication with external devices for storing data is required. When the host device captures the data output from the external device in synchronization with the clock supplied to the external device from the host device, the data output will be detected if there is a phase shift between the clock output from the external device and the data. There is a possibility that it cannot be latched at the valid timing. As the speed of data communication increases, there is a concern that a communication error may occur with a slight delay that was not a problem in the past.

  Taking an example of an imaging device that stores still images and moving image data on an SD card, the response from the SD card side after transmitting data and a CRC signal from the imaging device as a host to the SD card when writing to the SD card. The response output is slow, the phase shift from the clock becomes large, the host side cannot latch, and the possibility of failure in writing to the card increases. In addition, since the data output timing from the card differs depending on the type of card to be used and the temperature condition, the possibility of a write error becomes higher depending on the condition.

  With respect to this problem, Patent Document 1 discloses means for analyzing a data phase from an external device and correcting latch timing. For data that has been output predetermined calibration data to an external device, determine whether it matches the expected value of the calibration data stored in advance while changing the phase setting. Use the phase setting as the tuning result.

JP 2011-135551 A

  However, since tuning needs to read predetermined calibration data from an external device, it cannot be performed while writing to the external device. Also, real-time tuning is required in situations where the card temperature rises, such as during video recording by the imaging device. In that case, tuning can be performed only during the time when recording is not performed on the SD card until a predetermined amount of data is accumulated in the buffer memory inside the device. This time becomes shorter as card recording becomes faster.

  In the tuning according to the prior art disclosed in the above-mentioned patent document, the phase setting is not determined until it matches the expected value, so if the amount of phase deviation is large, it takes time to tune and the phase deviation due to temperature change is detected in real time. Tuning is not possible and high-speed writing cannot be performed.

  Accordingly, an object of the present invention is to provide a method for tuning a phase shift caused by a temperature change between a clock of a host device and data from an external device within a limited time, and enabling high-speed writing. is there.

  In order to achieve the above object, the present invention receives predetermined calibration data from an external device and delays a phase of a data latch by a predetermined amount with respect to the received data during a period when writing to the external device is not performed. And determining whether or not to latch each of a plurality of phase patterns acquired by changing the delay amount delayed by the delay means, and setting one of the latchable phases as a data latch phase An electronic apparatus having means for tuning a timing difference of data and means for acquiring the temperature of the external device unit, which can be acquired when the external device is first connected after the electronic apparatus is activated All phase patterns are acquired and tuned, and data recording to the external device is performed. Once the temperature of the external device unit is acquired at a predetermined time interval and the temperature change from when the previous latch phase correction was performed is equal to or greater than the threshold, the pause time during which recording to the external device is not performed the previous time, As many phase patterns as possible before and after a predetermined phase are acquired within the period, and a latch phase is selected therefrom.

  According to the present invention, it is possible to tune the phase shift of data from an external device accompanying a temperature change in a short time and perform high-speed writing to the external device.

It is a flowchart which shows the processing operation of an imaging device. It is a block diagram which shows the structure of an imaging device. It is a block diagram which shows the structure of a phase adjustment part. It is a figure which shows the tuning by all the phase acquisition. It is a figure which shows the data recording cycle at the time of moving image recording. It is a figure which shows the phase shift tuning by a temperature change. It is a figure which shows the difference in the tuning start position change presence or absence according to temperature.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[Example]
FIG. 2 is a block diagram illustrating a configuration of the lens unit exchangeable imaging apparatus 100 including the display device with a touch panel function according to the first embodiment of the present invention.

  An image sensor 121 forms an optical image of a subject (not shown) via a lens 210, an aperture 211, lens mounts 102 and 202, and a shutter 144, and converts the optical image into an electrical signal. Reference numeral 122 denotes an A / D converter that converts an analog signal output of the image sensor 121 into a digital signal. The digital signal A / D converted by the A / D converter 122 is controlled by the memory controller 124 and the system controller 120 and stored in the memory 127.

  An image processing unit 123 performs predetermined pixel interpolation processing and color conversion processing on the digital signal data A / D converted by the A / D conversion unit 122 or the data from the memory control unit 124. The image processing unit 123 also includes a compression / decompression circuit that compresses and decompresses image data by adaptive discrete cosine transform (ADCT) or the like. It is also possible to read an image stored in the memory 127, perform compression processing or decompression processing, and write the processed data to the memory 127.

  In addition, the image calculation unit 129 can calculate the contrast value of the captured image and measure the in-focus state of the captured image from the contrast value. It is possible to calculate the correlation value between the image data stored in the memory 127 and the current captured image and search for the region with the highest correlation. A memory control unit 124 controls transmission / reception of data between the A / D conversion unit 122, the image processing unit 123, the display device 110, the external removable memory unit 130, and the memory 127. The data of the A / D conversion unit 122 is written into the memory 127 via the image processing unit 123 and the memory control unit 124, or the data of the A / D conversion unit 122 is directly written via the memory control unit 124.

  Reference numeral 137 denotes a phase adjustment unit that adjusts the data latch phase so that data is read at an appropriate timing with respect to the clock when reading data from the external removable memory 130. Reference numeral 110 denotes a liquid crystal display type display device with a touch panel function, which includes a liquid crystal panel display unit 125, a backlight illumination unit 126, and a touch panel unit 151.

  A liquid crystal panel display unit 125 can display a menu screen stored in the image display data area of the memory 127 or an image file stored in the external removable memory unit 130 according to an instruction from the system control unit 120. It is. Further, “live view” shooting can be performed by sequentially displaying through-images of imaging data obtained from the imaging device in real time. During live view shooting, an AF frame indicating an AF area can be superimposed on the image and displayed on the display device 110 so that the operator can recognize the position of the subject to be AF.

  Reference numeral 126 denotes backlight illumination that irradiates the liquid crystal panel display unit 125 with the back surface. Examples of the light source element for backlight illumination include an LED, an organic EL, and a fluorescent tube. The illumination can be arbitrarily turned on or off according to an instruction from the system control unit 120. Reference numeral 151 denotes a touch panel unit, and examples of the touch detection method include a resistance film method and a capacitance method. The touch panel unit 151 enables intuitive device operations such as touch AF for focusing on a position touched by the operator.

  A system control unit 120 controls the entire imaging apparatus 100. Reference numeral 127 denotes a memory for storing captured still images and moving images, and image data for playback display, and has a sufficient storage capacity for storing a predetermined number of still images and moving images. In the memory 127, a program stack area, a status storage area, a calculation area, a work area, and an image display data area of the system control unit 120 are secured. Various calculations are executed by the system control unit 120 using the calculation area of the memory 127.

  Reference numeral 128 denotes an electrically erasable / recordable nonvolatile memory such as a flash memory or an EEPROM. The nonvolatile memory 128 stores a program for saving the shooting state and controlling the imaging device 100.

  Reference numeral 130 denotes an external detachable memory unit for recording and reading image files on a recording medium such as a compact flash (registered trademark) or an SD card. A power supply unit 131 includes a battery, a battery detection circuit, a DC-DC converter, a switch circuit that switches a block to be energized, and the like, and detects whether or not a battery is installed, the type of battery, and the remaining battery level. Further, the DC-DC converter is controlled based on the detection result and the instruction of the system control unit 120, and a necessary voltage is supplied to each block unit for a necessary period.

  Reference numeral 141 denotes a shutter control unit that controls the shutter 144 in cooperation with the lens control unit 203 that controls the diaphragm 211 based on photometric information from the photometric unit 142. A photometric unit 142 performs AE (automatic exposure) processing. The light beam incident on the lens 210 is incident on the photometry unit 142 through the aperture 211, the lens mounts 202 and 102, and the photometric lens (not shown), thereby measuring the exposure state of the image formed as an optical image. can do.

  A distance measuring unit 143 performs AF processing. Focusing of an image formed as an optical image by causing the light beam incident on the lens 210 to enter the distance measuring unit 143 via the aperture 211, the lens mounts 202 and 102, and a distance measuring mirror (not shown). The state can be measured. During live view shooting, it is possible to measure the in-focus state of the shot image according to the contrast value obtained from the image data output from the image calculation unit 129.

  Reference numeral 140 denotes a camera control unit that controls a series of operations as a camera by transmission and reception communication with the shutter control unit 141, the photometry unit 142, and the distance measurement unit 143. The camera control unit 140 can also control the lens unit 200.

  Reference numerals 132 and 133 denote a mode changeover switch and an operation unit, which are operation means for inputting various operation instructions to the system control unit 120. The mode switch 132 switches the operation mode of the system control unit 120 to any one of a still image recording mode, a moving image recording mode, a reproduction mode, and the like. As a mode included in the still image recording mode, an auto shooting mode, a manual mode, various scene modes that are shooting settings for each shooting scene, a program AE mode, and a live display that displays a through image in real time of imaging data obtained from the image sensor 121. View mode etc. Each operation member of the operation unit 133 is appropriately assigned a function for each scene by selecting and operating various function icons displayed on the display device 110, and functions as various function buttons.

  A release switch 134 is a switch that is turned on when the release button is half-pressed (SW1) and fully pressed (SW2). In the half-pressed state, the start of operations such as AF processing, AE processing, AWB (auto white balance) processing, and EF (flash dimming) processing is instructed. In the fully-pressed state, the image reading process for writing the signal read from the image sensor 121 to the memory 127 via the A / D converter 122 and the memory controller 124, and the calculation in the image processor 123 and the memory controller 124 are performed. The used development processing is performed.

  Further, the image data is read from the memory 127, compressed by the image processing unit 123, and instructed to start a series of processing operations such as recording processing for writing the image data to a recording medium (not shown) attached to the external removable memory unit 130. . Reference numeral 135 denotes a power switch that can switch and set the power-on and power-off modes of the imaging apparatus 100. In addition, the lens unit 200 connected to the imaging device 100 and various accessory devices such as a recording medium can be switched and set together.

  A timer 136 has a clock function, a calendar function, a timer counter function, and an alarm function, and is used for system management such as a transition time to the sleep mode and alarm notification. Reference numerals 102 and 202 denote lens mounts, which are interfaces for connecting the imaging apparatus 100 to the lens unit 200. Reference numerals 101 and 201 denote connectors that electrically connect the imaging apparatus 100 to the lens unit 200, and are controlled by the camera control unit 140.

  An interchangeable lens type lens unit 200 guides an optical image of a subject (not shown) from a lens 210 through an aperture 211, lens mounts 202 and 102, and a shutter 144, and forms an image on the image sensor 121. . A lens control unit 203 controls the entire lens unit 200. The lens control unit 203 is a memory for storing operation constants, variables, programs, etc., identification information such as numbers unique to the lens unit 200, management information, function information such as an open aperture value, minimum aperture value, focal length, And a function of a nonvolatile memory for holding past setting values and the like.

  The lens control unit 203 controls the focusing of the lens 210 according to the focus state of the image measured by the measurement distance unit 143 or the image processing unit 123, and changes the imaging position of the subject image incident on the image sensor 121. By doing so, it is possible to perform the AF operation. The lens control unit 203 also has a function of controlling the diaphragm 211 and zooming of the lens 210.

  Next, the configuration of the phase adjustment unit 137 will be described. FIG. 3 is a block diagram of the phase adjustment unit. A frequency divider 301 divides the PLL clock input from the clock generation unit to the latch phase adjustment unit to generate an SD clock. Reference numerals 302 and 305 denote flip-flops, and 302 delays the SD clock by one period with the PLL clock. Reference numeral 305 latches the SD data signal by a signal obtained by adding a predetermined delay to the clock signal output from the selector 303 by the delay circuit 304. A selector 303 outputs either the SD clock or the flip-flop 303 output.

  Which is output is selected by an instruction from the system control unit 120. Reference numeral 304 denotes a delay circuit. A plurality of delay elements that are delayed by a predetermined time shorter than one cycle of the SD clock are mounted, thereby adding a predetermined delay to the output signal of the selector 303. The amount of delay can be arbitrarily set by changing the number of stages of delay elements through which signals pass. In the present embodiment, description will be made assuming that the maximum number of stages of the delay circuit is 100.

  The presence or absence of garbled data when a predetermined test pattern signal is received from the SD card 130 according to an instruction from the system control unit 120 and the received data is latched with various delay amounts obtained by changing the settings of the selector 303 and the delay circuit 304. Judgment is performed, and tuning is performed by selecting and setting the optimum latch phase from among the latchable phases.

  A latch timing tuning method for the SD card 130 in the imaging apparatus 100 according to the first embodiment of the present invention will be described below with reference to the flowchart of FIG. In step S <b> 101, it is determined whether the SD card 130 is inserted after the imaging apparatus 100 is powered on. If it is detected that the SD card 130 is inserted, the process proceeds to step S102.

  In step S102, after the SD card 130 is mounted, the latch phase is tuned. Here, all the obtainable phase patterns are obtained, and an optimum latch phase is set from them. Such tuning by acquiring all phases is hereinafter referred to as “full tuning”. FIG. 4 shows the relationship between the clock signal, the SD data signal, and all acquired phase patterns. For the phase pattern, a total of 200 phase patterns are obtained for 100 stages of delay circuits for each of the two outputs from the selector. Areas indicated by 401, 403, 405, and 407 surrounded by solid lines are latchable areas.

  This is a place where data is stable, and if it is latched in this area, data corruption will not occur. Areas indicated by 402, 404, and 406 surrounded by broken lines are areas that cannot be latched. This is a data switching part, and if it is latched in this area, there is a possibility that data will be garbled. In the example shown in FIG. 4, the center phase 408 of the widest area 403 in the latchable areas is set as the optimum latch phase. The temperature To 139 of the SD card 130 at this time is acquired by the temperature sensor 139. Also record the time taken for full tuning.

  In step S103, the imaging apparatus 100 starts moving image recording. In step S104, the time during which recording on the SD card 130 is not performed during moving image shooting is calculated from the code rate, the recording speed on the SD card 130, and the recording unit. The code rate is a speed at which the imaging apparatus 100 performs the codec of the moving image, and is determined according to the resolution and the frame rate set by the user. The recording speed is a speed at which the coded moving image data is written to the SD card 130, and is set according to the SPEED CLASS of the SD card 130.

  The recording unit is the minimum data size written to the SD card 130 and is set by the system control unit 120. When the moving image file coded by this size is stored in the memory 127, writing to the SD card 130 is started. Here, the recording cycle of the SD card 130 during moving image shooting will be described with reference to FIG. The code rate is 12.5 MB / s, the recording speed is 15 MB / s, and the recording unit is 6 MB. A period of 480 msec indicated by t1 in the figure is a period in which moving image shooting is started, moving image data is encoded at 12.5 MB / s, and the data is stored in the memory 127.

  When 6 MB, which is a recording unit, is stored in the memory 127, recording of the data on the SD card 130 is started. A period of 400 msec indicated by t2 is a period in which writing to the SD card 130 and encoding are performed simultaneously. The amount of moving image data stored in memory decreases at 2.5 MB / s, which is the difference between the recording speed and the code rate. When 6 MB of data has been recorded on the SD card 130, recording on the SD card 130 is stopped and only encoding is performed. The period is a period of 80 msec indicated by t3. This is a period in which data is accumulated in the memory 127 by the amount decreased in the period t2.

  Since the accumulated amount of the buffer memory becomes 6 MB again in the period of t3, the recording to the SD card is started again. When the recording is completed, the recording is paused and the buffer memory is accumulated until the accumulated amount becomes 6 MB. Thereafter, the period of t2 and t3 is repeated until the moving image shooting is completed. As described above, the period t3 is a period in which recording to the SD card 130 is not performed, and is a tunable time during moving image shooting. In step S104, the time t3 is calculated.

In step S105, the execution time for the full tuning recorded in step S102, the total number of phase patterns, and the number of phase patterns that can be acquired within the SD card 130 recording pause time from the SD card 130 recording pause time calculated in step S104 are as follows. Calculated by the formula.
p1 = p0 × (tc1 / tc0)

  P1 represents the number of phase patterns acquired during the recording pause time of the SD card 130, and P0 represents the total number of phase patterns acquired in the full tuning in step S102. tc0 represents the total time required for the full tuning in step S102, that is, the time required for acquisition and selection and setting of all phase patterns, and tc1 represents the tunable time calculated in step S104.

  Here, it is assumed that in step S102, all 200 phase patterns are acquired in 200 msec in full tuning, and a total of 250 msec, which is 50 msec, is required for full tuning from that time to selection and setting of the latch phase. In this case, if the recording pause time of the SD card 130 calculated in step S104 is 80 msec, the number of acquired phase patterns is calculated to be 64 in 80 msec.

  In step S106, the temperature of the SD card 130 unit is acquired by the thermometer 139. In step S107, the difference between the temperature Tn acquired in step S106 and the temperature To acquired in step S102 is calculated, and it is determined whether or not the temperature increase amount after full tuning has reached a predetermined threshold or more due to the temperature increase due to moving image shooting. . If it is equal to or greater than the threshold value, the process proceeds to step S108.

  From step S108, since the temperature rise has become more than a predetermined value in step S107, latch phase tuning is performed during the tunable time calculated in step S104 in order to correct the data timing shift with respect to the SD clock caused by the temperature.

  In step S108, when the SD card 130 recording pause time is reached, the number of phase patterns before and after the currently set latch phase is acquired by the number calculated in step S105. In step S109, it is determined whether or not an unlatched area exists in the phase pattern acquired in step S108. If there is an area that cannot be latched, the process proceeds to step S110, and if there is no area that cannot be latched, the process proceeds to step S111.

  In step S110, since there is a non-latching area in the phase pattern acquired in step S108, the latch phase is changed to a phase farthest from the non-latching area in order to secure a margin for the non-latching area. In step S111, since there is no NG area in the phase pattern acquired in step S108, it is determined that the correction of the latch phase is unnecessary, and the tuning is finished without changing the latch phase.

  The tuning control in steps S108 to S110 will be described in detail with reference to FIG. FIG. 6 shows the relationship between the SD clock, the SD data signal before and after the temperature change, and the phase pattern. Reference numeral 408 denotes a latch phase before the change in step S110 set by the full tuning in step S102. The phase drawn with a solid line within the range indicated by 601 is the phase pattern acquired within the recording pause of the SD card 130 in step S108. Centering on 408, as many phase patterns as the number calculated in step S105 are applied. A phase drawn with a dotted line outside the range indicated by 601 is not acquired in step S108.

  Reference numerals 602 and 604 denote latchable areas, and 603 denotes an unlatching area. A non-latching area 603 exists near the current latch phase 408 in the range 601. Therefore, the latch phase is set to the phase indicated by 605 which is the maximum phase in the opposite direction to the non-latched area in the acquired phase pattern range 601.

  In this way, in a situation where the phase shift due to temperature change needs to be tuned in real time, full tuning is performed before the temperature rises, and the phase pattern is acquired as much as possible around the set latch phase. Among them, the latch phase is changed in a direction having a margin with respect to the unlatched area. In this way, even when there is no time for full tuning, it is possible to correct the latch phase in a direction that secures a timing margin against a temperature change and to perform high-speed writing.

  Note that the range of the latchable area and the non-latching area is different depending on the type of the SD card 130 to be used. Therefore, the range of the latchable area and the non-latching area is recorded at the time of the full tuning in step S102, and the temperature change amount threshold value for determining whether or not the tuning is performed in step S107 is changed according to the range. May be. Since the SD card 130 with a wide latchable area originally has a large timing margin and does not need to be tuned so frequently, the temperature change threshold is increased, and the SD card 130 with a narrow latchable area has a small timing margin. Since tuning needs to be performed frequently, the temperature change threshold value is reduced.

  This makes it possible to perform tuning at a timing that matches the characteristics of the SD card 130. Further, the data phase shift amount data of the SD card 130 corresponding to the temperature change amount is previously stored, and the start position when acquiring the phase pattern in step S108 is not the previous tuning position but the temperature change amount. It is good also as a phase shifted only. By doing so, it is possible to secure a margin in the tuning in a short time when the number of phases that can be acquired is limited. Details will be described with reference to FIG. Reference numeral 701 denotes a phase pattern range acquired during the recording pause period of the SD card 130.

  Reference numeral 702 denotes a tuning start phase when phase shift amount data based on a temperature change amount is not used, that is, a phase set in the previous tuning. In this case, since there is no non-latching area 704 within the phase acquired range, the latch phase is not changed from 702, but the non-latching area 704 is close to the position 702 and the margin is small. Next, reference numeral 703 denotes a phase shifted from 702 by a phase shift amount corresponding to the temperature change amount. Also in this case, since there is no unlatched area 704 within the phase acquired range, the latch phase is not changed from 703, but a margin can be secured for the latchable area 704 from the position 702.

  Thus, by performing tuning around the phase considering the amount of phase shift depending on the amount of temperature rise, it is possible to secure a margin in tuning in a shorter time. As for the data of the phase shift amount due to the temperature change amount at this time, an appropriate value may be given as a fixed value, or full tuning is performed at the end of moving image recording, and at that time, from the time of full tuning in step S102 You may make it predict based on the variation | change_quantity of the temperature change amount, and the optimal latching phase set.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

121 Image sensor 210 Lens 211 Apertures 102 and 202 Lens mount 144 Shutter 122 A / D converter 144 Memory controller 120 System controller 127 Memory

Claims (7)

A delay means for receiving predetermined calibration data from an external device and delaying a phase of a data latch by a predetermined amount with respect to the received data in a period in which writing to the external device is not performed;
It is determined whether or not to latch each of a plurality of phase patterns acquired by changing the delay amount delayed by the delay means, and one of the latchable phases is set as a data latch phase, so that the timing deviation between the clock and the data is reduced. Means to tune,
Means for obtaining the temperature of the external device,
When the external device is connected for the first time after startup, all the obtainable phase patterns are acquired and tuned, and when an operation for generating data recording to the external device is performed, the external device is set at a predetermined time interval. When the temperature change from when the previous latch phase correction was performed is equal to or greater than a threshold value, the phase before and after the predetermined phase is centered during the pause time when recording to the external device is not performed. An electronic apparatus characterized by acquiring as many patterns as possible within the period, and selecting a latch phase from the patterns.   If the phase pattern that is not latchable is not included in the phase pattern acquired during the recording pause time to the external device, the latch phase is not changed, and if the phase area that is not latchable is included, The electronic device according to claim 1, wherein a phase farthest from the latch phase impossible region is set as a latch phase.   The number of phase patterns acquired during the recording pause time to the external device is calculated from the number of acquired phases and the tuning execution time and the recording pause time to the external device in the tuning performed by acquiring all the phase patterns. The electronic device according to claim 1, wherein:   During tuning performed by acquiring all the phase patterns, the ranges of the latchable phase region and the non-latching phase region are recorded, and the temperature change threshold is changed according to the size of each range. The electronic device according to claim 1.   During tuning when the temperature change occurs, the number of phase patterns before and after the currently set phase is acquired as many as possible within the period, and a latch phase is selected from the obtained number. The electronic device according to claim 1. Having data output timing data from the external device with respect to the temperature change amount;
The phase as the center of phase acquisition at the time of tuning when the temperature change occurs is a phase shifted from the currently set phase by an amount calculated from the temperature change amount by the timing data. The electronic device according to claim 1. When the operation to generate data recording to the external device is completed, perform the tuning to obtain all the phase patterns, calculate the phase shift amount with respect to the temperature change amount from the temperature information and the phase correction amount at that time,
The phase as the center of phase acquisition at the time of tuning when the temperature change occurs is a phase shifted from the currently set phase by an amount calculated from the phase shift amount with respect to the temperature change amount. The electronic device according to claim 1.