JP2011059762A - System and method for controlling memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set a plurality of parameters necessary for memory access between a memory and a memory controller according to an environment in a device. <P>SOLUTION: A memory control system is configured of: a memory control part 10; a memory controller 20; and a memory 30, wherein a plurality of parameters between the memory 30 and the memory controller 20 are set. An adjustment method determination means 104 of the memory control part 10 determines a calibration method matched with the environmental change of the inside of the device from the plurality of calibration methods of the parameter, and a parameter setting means 105 sets a parameter by the determined calibration method, and a setting value storage means 106 stores the set setting value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a memory control system and a memory control method, and more particularly to a memory control system and a memory control method for setting memory parameters.

In recent years, a double data rate SDRAM that operates in synchronization with a complementary clock signal is used as a main memory for a high-speed MPU. This double-rate memory is a memory in which data signals (DQ) are read and written in synchronization with both the rising timing and falling timing of the data strobe signal (DQS), and is a DDR-SDRAM (Double Data Rate Dynamic Random Access). Memory) and DDR2 and DDR3 established by the JEDEC (Joint Electron Device Engineering Council) Semiconductor Technology Association as standards for further speeding up DDR.
By the way, since the operating frequency of these memories reaches several hundred MHz, the timing margin for accessing the memory is extremely small, and the influence of the skew due to the pattern of the printed circuit board on the signal quality cannot be ignored.

Therefore, in order to deal with such problems, various on-off switching of ODT (On Die Termination), ODT resistance value setting, fine adjustment of write data latch timing, fine adjustment of read data latch timing, etc. Memory controllers with adjustment functions have been developed.
By the way, when the number of adjustment functions increases, the number of parameters set for each function increases, and accordingly, the number of parameter combinations also increases. Further, since the optimum parameter changes when the environment of the apparatus changes, it takes a lot of time to find the optimum parameter.

Therefore, a memory control system has already been proposed that adjusts the parameters at regular intervals to adjust the parameters to match the internal environment of the device that changes over time, and responds to environmental changes such as temperature and humidity. (See Patent Document 1).
The memory control system includes delay adjustment means for adjusting a delay value by delaying a data strobe signal (DQS), writing a specific value to a specific address, and changing the delay value of the delay adjustment means, Read to the same address as the address, compare both values and recognize whether or not the correct value was read, recognize the readable range, the intermediate value of the recognized readable range, that is, the range of verify OK is the delay adjustment means Is set to
Although this memory control system certainly allows readjustment of parameters, all calibrations (herein, calibration and setting of parameters are referred to as calibration) are performed at regular intervals. Even in the case where it can be completed, there is still a problem in that it takes time unnecessarily for full calibration.

For example, in recent years, multifunction devices equipped with functions such as printing, copying, scanning, and faxing in a single device have been widely equipped with an energy saving mode. During periods when it is not used, power consumption is reduced by shifting to the energy-saving mode. In this apparatus, the environment (temperature and humidity, etc.) inside the apparatus changes not only in the usage state (frequency of printing, copying, scanning, FAX, etc.) but also before and after the energy saving transition. Therefore, it is necessary to set the parameters more frequently that determine the electrical characteristics related to memory access such as DDR-SDRAM.
When such a conventionally known memory control system is adopted in such an apparatus, there is a problem that the time for full calibration becomes longer.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to perform calibration in a shorter time in a memory control system that can be calibrated.

(1) The present invention is a memory control system that includes a memory control unit, a memory controller, and a memory, and sets a plurality of parameters necessary for memory access between the memory and the memory controller. The control unit is a calibration method determination unit that determines a calibration method that matches a change in the environment inside the apparatus from a plurality of calibration methods for the parameter, and is subject to calibration according to the determined calibration method. A memory control system comprising: means for calibrating parameters; and setting value storage means for storing parameter setting values set by the calibration.
(2) Another invention of the present application includes a memory control unit, a memory controller, and a memory, and memory control in a memory control system that sets a plurality of parameters necessary for memory access between the memory and the memory controller. The memory control unit is a calibration method determining step for determining a calibration method suitable for an environmental change in the apparatus from a plurality of adjustment methods of the parameters, and the calibration according to the determined calibration method. A memory control method in a memory control system, comprising: a step of calibrating a target parameter, and a setting value storing step of storing a parameter setting value set by the calibration.
(3) Still another invention of the present application is a program for causing a computer to execute each step of the memory control method in the memory control system described in (2) above.
(4) Still another invention of the present application is a computer-readable recording medium recording the program described in (3) above.

  According to the present invention, from a plurality of calibration methods, calibration is performed by discriminating a calibration method suitable for the situation, such as full calibration when the environmental change is large, and simple calibration when the environmental change is small. As a result, the total time required for calibration can be shortened as compared with the prior art.

It is a block diagram which shows roughly the function structure of the memory control system which sets a memory parameter based on embodiment of this invention. It is a block diagram which shows roughly the structure of a calibration method determination means. It is a block diagram which shows roughly the structure of a parameter setting means. It is a flowchart which shows the calibration implementation procedure performed in a memory control system.

Embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a block diagram schematically showing a functional configuration of a memory control system for setting memory parameters according to an embodiment of the present invention.
This memory control unit system includes a memory control unit 10, a memory controller 20 connected to the memory control unit 10, and a double rate type memory (DDR-SDRAM, DDR2-SDRAM, DDR3- The memory control unit 10 accesses the memory 30 via the memory controller 20.

  The memory control unit 10 includes a time measuring unit 101, a temperature monitoring unit 102, a voltage monitoring unit 103, a calibration method determining unit 104, a parameter setting unit 105, a set value storage unit 106, and a calibration method storage unit 107. It consists of.

The time measuring means 101 is a means for measuring time, such as RTC (Real Time Clock).
The temperature monitoring unit 102 is a unit that monitors the temperature inside the apparatus, and is a temperature sensor installed inside the device, a thermal diode that monitors the internal temperature of the memory controller, or the like.
The voltage monitoring unit 103 is a unit that monitors the voltage value of the supply voltage of the memory or the memory controller.

  As shown in FIG. 2, the calibration method determination unit 104 is a calibration necessity determination unit 104 (1) that determines whether adjustment is necessary from various pieces of input information, and a method for readjusting a plurality of memory parameters. Calibration method determining means 104 (2) for determining a calibration method from the inside, and notification means 104 (3) for notifying the parameter setting means of the calibration method and the calibration execution command are provided.

  Here, information used for determining whether or not calibration is necessary includes (i) time information by the time measuring means 101, (ii) temperature information from the temperature monitoring means 102 by the temperature sensor, and (iii) from the voltage monitoring means 103. The calibration method determination unit 104 is programmed to perform parameter recalibration at a predetermined timing.

  As shown in FIG. 3, the parameter setting unit 105 includes a parameter management unit 105 (1), a test unit 105 (2) that performs a read / write / verify test, and a parameter determination unit 105 ( 3) and parameter setting means 105 (4) for setting parameters, etc., and a read / write / verify test is performed according to the calibration method determined by the calibration method determining means 104, and the memory is Set the parameters. Also, it has a function of reading or writing setting values with the setting value storage means 106.

The set value storage means 106 may also store test results when performing a read / write / verify test in calibration of parameters for recording / holding memory parameter setting information.
Examples of storage means include programs stored in non-volatile storage devices such as HDD (hard disk drive) and SSD (solid state drive or solid state disk), or DRAM (Dynamic Random Access Memory) in which the program is expanded, etc. Such as volatile memory.

The calibration method storage means 107 is a means for storing a calibration method in a parameter, and stores a plurality of calibration methods.
As a calibration method, for example, there are the following methods.
(1) Full calibration: a calibration method for testing all parameter combinations.
(2) Detailed calibration: A calibration method in which adjustment time can be shortened compared to full calibration by narrowing down the combination of parameters.
(3) Simple calibration: a calibration method that can significantly reduce the adjustment time by further narrowing down the combination of parameters than the detailed calibration. It is assumed to be implemented when the environmental change is small.
As the storage means, there is a nonvolatile storage device such as an HDD or an SSD in which a program is stored, or a volatile memory such as a DRAM in which the program is expanded.

  The memory controller 20 includes parameters (registers), has a function of transmitting a signal to the memory 30 and a function of receiving a signal from the memory 30, and serves as an interface between the memory 30 and the memory control unit 10.

FIG. 4 is a flowchart showing a calibration execution procedure executed in the memory control system having the above configuration.
In FIG. 4, first, the power of the device is turned on (S101), and the parameter setting means 105 performs initial parameter settings (S102). As a result, the device enters a standby state (S103). Here, the necessity of the parameter calibration method is determined by the calibration method determination means 104 (S104).
If calibration is not necessary (S104, NO), the process returns to the standby state in step S103. If calibration is necessary (S104, YES), the calibration method determination unit 104 then performs full calibration for the calibration method. Whether the calibration is detailed calibration or simple calibration (S105), the calibration method and the calibration execution instruction are notified to the parameter setting means 105. Full calibration is performed to determine memory parameters (S106). If it is a detailed calibration, a detailed calibration is performed by the parameter setting means 105 to determine a memory parameter (S107). If it is simple calibration, simple calibration is performed by the parameter setting means 105 to determine a memory parameter (S108). Thereafter, parameters are set by the parameter setting means 105 (S109).

Next, details of the processing of steps S104, S105, and S108 will be described.
Explanation of Processing in (Step S104) As a method for determining the necessity of calibration by the calibration method determining means 104, there are the following methods.
(1) A method for determining whether calibration is necessary based on input information from the temperature monitoring unit 102, the voltage monitoring unit 103, and the time measuring unit 101. In particular,
(I) A method of determining that calibration is necessary when the time change of temperature is large based on information of the temperature monitoring unit 102 and the time measuring unit 101.
(Ii) A method of determining that the calibration is necessary when the time change of the voltage is large based on the information of the voltage monitoring unit 103 and the time measuring unit 101.
(2) A method of programming to perform calibration at a predetermined timing.
According to this method, the temperature monitoring means and the voltage monitoring means as described in the above (1) are unnecessary, and the cost can be reduced accordingly.

In the method (2) above, in the case of an image forming apparatus such as a multifunction peripheral,
(i) After completion of a job such as printing, copying, scanning, and faxing, it is determined that calibration is necessary, and calibration is performed. It rises and changes in the environment increase. Therefore, programming is performed in advance so that calibration is performed at an appropriate timing after these operations.
(ii) After printing, copying, scanning, and faxing, when there is no new job for a certain period, it is determined that calibration is necessary, and calibration is performed, that is, the temperature inside the device rises due to execution of the job. After that, when there is no new job for a certain period, the temperature inside the device is lowered, and it is determined that calibration is necessary.

Explanation of processing in (Step S105) Basically, the calibration method is determined by full calibration when the environmental change is large, detailed calibration when the environmental change is middle, and simple calibration when the environmental change is small. desirable.
As a determination method of the calibration method, there are the following methods.
(1) A method for determining full, detailed, or simple calibration based on input information from the temperature monitoring unit 102, the voltage monitoring unit 103, and the time measuring unit 101. In particular,
(I) Based on the information of the temperature monitoring means 102 and the time measuring means 101, full, detailed or simple calibration is determined according to the magnitude of the temperature change over time.
(Ii) A method for determining full, detailed, or simple calibration based on the magnitude of the time change in voltage based on information of the voltage monitoring unit 103 and the time measuring unit 101.
(2) A method of programming so as to determine whether full calibration, detailed calibration, or simple calibration is performed at a predetermined timing.

In the method (2) above, in the case of an image forming apparatus such as a multifunction peripheral,
(I) After printing, copying, and FAX reception, in the case of full calibration, scanning, and FAX transmission, it is determined that simple calibration is performed.
That is, in the former case, since the engine operates, the temperature rise inside the device increases. Therefore, it is determined to be full calibration.
In the latter case, the memory controller 20 operates, but the engine does not operate. Therefore, the temperature rise inside the device is considered to be limited, and it is determined that the simple calibration is performed.
(Ii) Immediately after the power is turned on, it is determined as full calibration. In this case, it is better to perform full calibration since there is a rapid temperature change after the power is turned on.
(Iii) When returning from the energy saving mode, it is determined to be simple calibration.

  In the above (iii), that is, at the time of return from the energy saving mode, the internal environment change (for example, temperature rise) increases rapidly. On the other hand, returning from the energy-saving mode means that there is a request to execute some job, so calibration is performed because there is a sudden temperature change, but it takes time. If it passes, the execution of the job will be delayed, and the user will be stressed. Therefore, by determining that the simple calibration is performed when returning from the energy saving mode, it is possible to improve the memory access quality to a certain degree and to prevent the user from feeling stress. At that time, in order to improve the memory access quality even when performing simple calibration, the setting value set by full calibration immediately after the power is turned on is set as the default, and then the method of performing simple calibration is adopted. Good.

Explanation of Processing in (Step S108) Next, simple calibration will be described.
(1) Calibration is performed by narrowing the setting value candidates of each parameter to values close to the current setting. Thereby, the number of parameter combinations is greatly reduced, and the calibration time can be greatly reduced. Parameters that are susceptible to environmental changes have a relatively wide setting range (for example, up to ± 3 levels of the current setting value), and parameters that are not easily affected have a relatively narrow setting range (for example, ± 1 of the current setting value). By changing the swing width (setting range) according to the parameter as in the case of the stage, it is possible to improve the parameter setting quality and improve the time reduction effect.

(2) Calibration is performed by reducing the number of calibration target parameters themselves. In this case, a plurality of parameters are classified into parameters that are easily affected by environmental changes and parameters that are difficult to be affected, and only the parameters that are easily affected are calibrated.
(3) Calibration time can be further reduced by a combination of (1) and (2) calibration.

The detailed calibration performed in step S107 can allow the operator to arbitrarily select a calibration item between full calibration and the above-described simple calibration, for example.
Note that this detailed calibration can be omitted and only full calibration and simple calibration can be performed.

The calibration execution procedure executed in the memory control system has been described above. These processes create a computer program that records the calibration execution procedure and instructions, and this is a computer that controls the entire memory control system unit ( (Not shown).
The computer program can be recorded on a known recording medium such as a computer-readable CD-ROM or DVD-ROM.

Although the embodiment of the present invention has been described, the features are summarized as follows.
(1) In a memory control system, a plurality of parameters calibration methods are set in a memory control system for setting a plurality of parameters for determining a memory operation between a memory and a memory controller. Calibration according to the situation can be performed.
(2) Since at least one of the plurality of calibration methods is a simplified version of the other calibration methods (hereinafter referred to as simple calibration), the calibration time can be shortened when simple calibration is selected.
(3) Since the simple calibration can narrow the set value candidates of each parameter to a value close to the current set value, that is, for example, by narrowing down to the set value of ± 1 step of the current set value, The number of combinations is greatly reduced and the calibration time can be greatly reduced.
(4) In the detailed or simple calibration, since the types of target parameters to be calibrated are limited, the number of parameter combinations can be reduced to a certain level or greatly, and the calibration time can be reduced to a certain level or greatly.

  DESCRIPTION OF SYMBOLS 10 ... Memory control part, 20 ... Memory controller, 30 ... Memory, 101 ... Time measuring means, 102 ... Temperature monitoring means, 103 ... Voltage monitoring means, 104 ... Calibration Method determining means, 105... Parameter setting means, 106... Setting value storage means, 107.

JP 2003-99321 A

Claims (12)

A memory control system comprising a memory control unit, a memory controller, and a memory, and sets a plurality of parameters necessary for memory access between the memory and the memory controller,
The memory control unit includes a calibration method determination unit that determines a calibration method that matches a change in environment inside the apparatus from a plurality of calibration methods for the parameter;
Means for calibrating the parameters to be calibrated according to the determined calibration method;
Setting value storage means for storing setting values of parameters set by the calibration;
A memory control system comprising: The memory control system of claim 1, wherein
The memory control system according to claim 1, wherein the environmental change is at least one of a temperature change in the machine, a change in the same voltage, a lapse of time, a power ON, a return from an energy saving state, and an operation stop. The memory control system according to claim 1 or 2,
At least one of the plurality of calibration methods is a memory control system in which the number of parameters in other calibration methods is limited. The memory control system according to claim 1 or 2,
A memory control system characterized in that simple calibration is performed by narrowing the set value candidates for each parameter to a value close to the current set value. The memory control system according to claim 1 or 2,
The simple calibration is performed by limiting the number of parameters to be adjusted. A memory control method in a memory control system, comprising a memory control unit, a memory controller, and a memory, and sets a plurality of parameters required for memory access between the memory and the memory controller,
The memory control unit is a calibration method determination step for determining a calibration method suitable for an environmental change inside the apparatus from a plurality of adjustment methods of the parameters;
Calibrating the parameters to be calibrated according to the determined calibration method;
A set value storing step for storing set values of parameters set by the calibration;
A memory control method in a memory control system. A memory control method in the memory control system according to claim 6, comprising:
The memory control method in a memory control system, wherein the environmental change is at least one of a temperature change in the machine, a change in the same voltage, a lapse of time, a power ON, a return from an energy saving state, and an operation stop. A memory control method in a memory control system according to claim 6 or 7, comprising:
A memory control method in a memory control system, wherein at least one of the plurality of calibration methods has a limited number of parameters in another calibration method. A memory control method in a memory control system according to claim 6 or 7, comprising:
A memory control method in a memory control system, wherein the simple calibration is performed by narrowing the set value candidates of each parameter to a value close to a current set value. A memory control method in a memory control system according to claim 6 or 7, comprising:
The memory control method in a memory control system, wherein the simple calibration is performed by limiting the number of parameters to be adjusted.   A program for causing a computer to execute each step of the memory control method in the memory control system according to claim 6.   A computer-readable recording medium on which the program according to claim 11 is recorded.

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