阅读说明：本技术 存储器系统及其存储器访问接口装置 (Memory system and memory access interface device thereof ) 是由 蔡福钦 余俊锜 张志伟 周格至 于 2021-04-06 设计创作，主要内容包括：本申请涉及一种存储器访问接口装置。时钟产生电路产生命令参考时钟信号。访问信号传输电路根据命令参考时钟信号调整包括外部读取使能信号及内部读取使能信号的访问信号的相位以及工作周期,以产生包括用以驱动存储设备的输出外部读取使能信号及输出内部读取使能信号的输出访问信号。数据读取电路根据取样信号对存储设备的数据信号进行取样,产生并传送读取数据信号至存储器访问控制器。多工器在单倍数据速率模式下根据输出内部读取使能信号产生取样信号,在双倍数据速率模式下根据来自被驱动的存储设备的数据选通信号产生取样信号。(The present application relates to a memory access interface apparatus. The clock generation circuit generates a command reference clock signal. The access signal transmission circuit adjusts a phase and a duty cycle of an access signal including an external read enable signal and an internal read enable signal according to a command reference clock signal to generate an output access signal including an output external read enable signal and an output internal read enable signal to drive the memory device. The data reading circuit samples the data signal of the storage device according to the sampling signal, generates and transmits a read data signal to the memory access controller. The multiplexer generates a sampling signal according to the output internal read enable signal in a single data rate mode and generates a sampling signal according to a data strobe signal from a driven memory device in a double data rate mode.)

1. A memory access interface device, comprising:

a clock generation circuit configured to generate a command reference clock signal;

a plurality of access signal transmission circuits respectively configured to adjust a phase and a duty cycle of one of a plurality of access signals from a memory access controller according to the command reference clock signal to generate one of a plurality of output access signals, wherein the access signals include an external read enable signal and an internal read enable signal, and the output access signals include an output external read enable signal and an output internal read enable signal, wherein the output external read enable signal is used for driving a memory device;

a data read circuit configured to sample a data signal from the memory device being driven according to a sampling signal to generate and transmit a read data signal to the memory access controller; and

a multiplexer is configured to generate the sampling signal based on the output internal read enable signal in a single data rate mode and to generate the sampling signal based on a data strobe signal from the memory device being driven in a double data rate mode.

2. The memory access interface device of claim 1, further comprising;

a first clock divider circuit configured to divide the frequency of the command reference clock signal to generate a first divided clock signal; and

a second clock divider circuit configured to divide the frequency of the first divided clock signal to generate a second divided clock signal;

wherein the access signal transmission circuit adjusts the phase of the access signal according to the second divided clock signal and adjusts the duty cycle of the access signal according to the first divided clock signal.

3. The memory access interface device of claim 2, wherein each of the access signal transmission circuits further comprises:

a phase adjustment circuit configured to receive a corresponding one of the access signals from the memory access controller to adjust the phase according to the second divided clock signal to generate a phase adjusted access signal; and

a duty cycle adjustment circuit configured to adjust the duty cycle of the phase adjusted access signal in accordance with the first divided clock signal to generate a corresponding one of the output access signals.

4. The memory access interface device of claim 1, wherein the access signal further comprises a data strobe enable signal, and the output access signal further comprises an output data strobe enable signal;

wherein the memory access interface device further comprises an enable circuit configured to receive the output data strobe enable signal and the data strobe signal and enabled by the output data strobe enable signal to output an enable data strobe signal, such that the multiplexer selects the enable data strobe signal as the sampling signal in the double data rate mode.

5. The memory access interface device of claim 1, further comprising an inverter configured to receive the output internal read enable signal to generate an inverted output internal read enable signal, such that the multiplexer selects the inverted output internal read enable signal as the sampling signal in the single data rate mode.

6. The memory access interface device of claim 1, wherein the internal read enable signal and the external read enable signal have a same operating frequency;

the phases of the internal read enable signal and the external read enable signal are synchronized in a first speed operating state in the single data rate mode;

the phase of the internal read enable signal lags the phase of the external read enable signal by one-half period relative to the phase of the external read enable signal in a second speed operating state of the single data rate mode;

wherein the first speed operating state corresponds to the operating frequency being below a preset value and the second speed operating state corresponds to the operating frequency being not below the preset value.

7. The memory access interface device of claim 1, wherein in the single data rate mode, the data read circuit is configured to sample the data signal according to one of two edges of each sampling period of the sampling signal to generate the read data signal, or to sample according to the two edges of each sampling period of the sampling signal and discard a plurality of sampling results generated according to one of the two edges to generate the read data signal.

8. The memory access interface device of claim 1, wherein the memory device is a NAND flash memory operating in a single data rate mode or a double data rate mode.

9. A memory system, comprising:

a memory access controller;

a storage device; and

a memory access interface device, comprising:

a clock generation circuit configured to generate a command reference clock signal;

a plurality of access signal transmission circuits respectively configured to adjust a phase and a duty cycle of one of a plurality of access signals from the memory access controller according to the command reference clock signal to generate one of a plurality of output access signals, wherein the access signals include an external read enable signal and an internal read enable signal, and the output access signals include an output external read enable signal and an output internal read enable signal, wherein the output external read enable signal is used for driving the memory device;

a data read circuit configured to sample a data signal from the memory device being driven according to a sampling signal to generate and transmit a read data signal to the memory access controller; and

a multiplexer is configured to generate the sampling signal based on the output internal read enable signal in a single data rate mode and to generate the sampling signal based on a data strobe signal from the memory device being driven in a double data rate mode.

10. The memory system of claim 9, wherein the internal read enable signal and the external read enable signal have a same operating frequency;

the phases of the internal read enable signal and the external read enable signal are synchronized in a first speed operating state in the single data rate mode;

the phase of the internal read enable signal lags the phase of the external read enable signal by one-half period relative to the phase of the external read enable signal in a second speed operating state of the single data rate mode;

wherein the first speed operating state corresponds to the operating frequency being below a preset value and the second speed operating state corresponds to the operating frequency being not below the preset value.

Technical Field

The present invention relates to memory technologies, and in particular, to a memory system and a memory access interface device thereof.

Background

NAND flash memories used in the earliest days a low speed Single Data Rate (SDR) mode architecture. However, as the bandwidth requirement of the product gradually increases, the traditional single data rate mode architecture cannot be used and cannot achieve the speed requirement. Therefore, non-volatile double data rate (NVDDR) mode architectures have been proposed to break through the speed limitation.

Under this architecture, increasingly high speed non-volatile double data rate specifications are being proposed. However, all controllers on the market are required to be able to support all speed modes, as well as having signal correction capability.

Disclosure of Invention

In view of the problems of the prior art, it is an object of the present invention to provide a memory system and a memory access interface device thereof, so as to improve the prior art.

One object of the present invention is to provide a memory access interface device, one embodiment of which includes: the device comprises a clock generating circuit, a plurality of access signal transmission circuits, a data reading circuit and a multiplexer. The clock generation circuit is configured to generate a command reference clock signal. The access signal transmission circuits are respectively configured to adjust a phase and a duty cycle of one of a plurality of access signals from the memory access controller according to the command reference clock signal to generate one of a plurality of output access signals, wherein the access signals include an external read enable signal and an internal read enable signal, and the output access signals include an output external read enable signal and an output internal read enable signal, wherein the output external read enable signal is used for driving the memory device. The data reading circuit is configured to sample a data signal from a driven memory device according to the sampling signal to generate and transmit a read data signal to the memory access controller. The multiplexer is configured to generate a sampling signal based on the output internal read enable signal in the single data rate mode and a sampling signal based on a data strobe signal from a driven memory device in the double data rate mode.

It is another object of the present invention to provide a memory system, one embodiment of which includes: a memory access controller, a memory device, and a memory access interface apparatus. The memory access interface device comprises a clock generating circuit, a plurality of access signal transmission circuits, a data reading circuit and a multiplexer. The clock generation circuit is configured to generate a command reference clock signal. The access signal transmission circuits are respectively configured to adjust a phase and a duty cycle of one of a plurality of access signals from the memory access controller according to the command reference clock signal to generate one of a plurality of output access signals, wherein the access signals include an external read enable signal and an internal read enable signal, and the output access signals include an output external read enable signal and an output internal read enable signal, wherein the output external read enable signal is used for driving the memory device. The data reading circuit is configured to sample a data signal from a driven memory device according to the sampling signal to generate and transmit a read data signal to the memory access controller. The multiplexer is configured to generate a sampling signal based on the output internal read enable signal in the single data rate mode and a sampling signal based on a data strobe signal from a driven memory device in the double data rate mode.

The features, implementations and functions of the present disclosure will be described in detail with respect to preferred embodiments with reference to the accompanying drawings.

Drawings

FIG. 1 is a block diagram of a memory system according to an embodiment of the present invention;

FIG. 2 is a more detailed block diagram of the memory access interface device of FIG. 1 according to one embodiment of the present invention;

FIGS. 3A, 3B, and 3C are waveform diagrams illustrating signals associated with operation of the memory access interface device in a single data rate mode according to an embodiment of the present invention; and

FIG. 4 is a waveform diagram illustrating signals associated with operation of the memory access interface device in double data rate mode according to an embodiment of the present invention.

Detailed Description

An object of the present invention is to provide a memory system and a memory access interface device thereof.

Please refer to fig. 1. FIG. 1 shows a block diagram of a memory system 100 according to an embodiment of the invention. The memory system 100 includes a memory access controller 110, a memory access interface device 120, and a storage device 130.

Memory system 100 may be electrically coupled to other modules through, for example, but not limited to, a system bus (not shown). For example, memory system 100 may be electrically coupled to a processor (not shown) through a system bus to enable the processor to access memory system 100.

In one embodiment, the memory access interface device 120 may be, for example, but not limited to, a physical layer circuit.

Preferably, memory device 130 is a NAND flash memory that is supportable from a lower speed single data rate mode to a higher speed double data rate mode such as NVDDR1, NVDDR2, or NVDDR 3.

External access signals, such as access signals from a processor, may be received by the memory access controller 110 and then transmitted to the memory access interface device 120. Further, the access signal may be transmitted from the memory access interface device 120 to the memory device 130, or may be used as a reference signal at the memory access interface device 120 to access the memory device 130.

In more detail, in one embodiment, the memory access controller 110 may receive and transmit access signals, wherein the access signals may include, for example, but not limited to, an external read enable signal EREN, an internal read enable signal IREN, and a data strobe enable signal (data strobe enable) DSEN.

Based on the signals, the memory access interface 120 may drive (activate) the memory device 130, receive the data signal DQ from the driven memory device 130 and sample the data signal DQ to generate the read data signal RDQ, and transmit the read data signal RDQ to the memory access controller 110.

Thus, the internal data stored in the memory device 130 can be accessed according to the correct timing of the signals.

The memory access interface means 120 actually comprise a receiver RX and a transmitter TX. The following paragraphs describe the structure and operation of the receiver RX in more detail.

Please refer to fig. 2. FIG. 2 is a more detailed block diagram of the memory access interface device 120 of FIG. 1 according to one embodiment of the present invention. It is noted that in fig. 2, only the receiver RX of the memory access interface device 120 is shown, and the transmitter TX is not shown.

The memory access interface device 120 includes a clock generating circuit 200, a plurality of access signal transmitting circuits 210-230, a data reading circuit 240 and a multiplexer 250.

The clock generation circuit 200 is configured to generate a command reference clock signal CMDCLK.

In one embodiment, the memory access interface device 120 further includes a first clock divider circuit 260A and a second clock divider circuit 260B. The first clock division circuit 260A is configured to divide the frequency of the command reference clock signal CMDCLK to generate a first divided clock signal CMDCD 1. The second clock dividing circuit 260B is configured to divide the frequency of the first divided clock signal CMDCD1 to generate a second divided clock signal CMDCD 2.

Each of the access signal transmission circuits 210-230 adjusts the phase (phase) of one of the access signals according to the second frequency-divided clock signal CMDCD2, and adjusts the duty cycle (duty cycle) of one of the access signals according to the first frequency-divided clock signal CMDCD 1.

The access signal transmitting circuits 210-230 include an external read enable signal transmitting circuit 210, an internal read enable signal transmitting circuit 220, and a data strobe enable signal transmitting circuit 230.

Taking the external read enable signal transmission circuit 210 as an example, the external read enable signal transmission circuit 210 includes a phase adjustment circuit 212 and a duty cycle adjustment circuit 214.

Phase adjustment circuit 212 is configured to receive external read enable signal EREN from memory access controller 110 to adjust the phase of external read enable signal EREN based on second divided clock signal CMDCD2 to generate phase adjusted access signal ERP.

In one embodiment, the phase adjustment circuit 212 may include at least one flip-flop (flip-flop) to sample the external read enable signal EREN according to the phase of the second divided clock signal CMDCD2 to achieve the phase adjustment mechanism.

In one embodiment, when the rising edge (rising edge) of the second frequency-divided clock signal CMDCD2 is within the set-up and hold time (set-up and hold time) of the waveform of the external read enable signal EREN, a timing violation problem easily occurs since the set-up and hold time is a transition time of the waveform of the external read enable signal EREN transitioning from a low state to a high state.

Therefore, in one embodiment, the phase adjustment circuit 212 may adjust the phase of the external read enable signal EREN according to sampling results of rising and falling edges (falling edges) of the second divided clock signal CMDCD 2. In one embodiment, when transitions of the signals are not sampled by a rising edge of the second divided clock signal CMDCD2, but are sampled by a falling edge of the second divided clock signal CMDCD2, the phase adjustment circuit 212 may adjust the phase of the external read enable signal EREN based on, for example, but not limited to, the falling edge of the second divided clock signal CMDCD 2.

It should be noted that the structure of the phase adjustment circuit 212 is merely an example. In other embodiments, the phase adjustment circuit 212 may have a different structure.

The duty cycle adjustment circuit 214 is configured to adjust the duty cycle of the phase adjusted access signal ERP according to the first divided clock signal CMDCD1 to generate and transmit the output external read enable signal ERENO to the memory device 130. The memory device 130 is thus driven by outputting the external read enable signal ERENO to transfer the data signal DQ to the memory access interface device 120.

To support the double data rate mode, in which data is sampled on both rising and falling edges, the duty cycle adjustment circuit 214 operates according to the first divided clock signal CMDCD1 having a higher speed. The duty cycle adjustment circuit 214 may be used to fine tune the duty cycle of the phase adjusted access signal ERP to be 50-50, i.e., half cycles. The adjusted result may be output as an output external read enable signal ERENO. It should be noted that in practice, the duty cycle may have reasonable errors from the full precision half cycle period due to component errors.

On the other hand, the internal read enable signal transmission circuit 220 receives the internal read enable signal IREN and adjusts the phase and duty cycle of the internal read enable signal IREN to output the internal read enable signal IRENO.

Further, the data strobe enable signal transfer circuit 230 receives the data strobe enable signal DSEN and adjusts a phase and a duty cycle of the data strobe enable signal DSEN to generate the output data strobe enable signal DSENO.

In one embodiment, the internal read enable signal transmitting circuit 220 and the data strobe enable signal transmitting circuit 230 each include the same elements and operation mechanisms as the external read enable signal transmitting circuit 210, and thus are not described in detail.

The data read circuit 240 is configured to sample the data signal DQ from the driven memory device 130 according to the sampling signal SS to generate and transmit a read data signal RDQ to the memory access controller 110.

The multiplexer 250 is configured to generate the sampling signal SS according to at least one signal from the access signal transmission circuits 210-230 and the driven memory device 130 in different operation modes, such as a single data rate mode and a double data rate mode.

Please refer to fig. 3A, fig. 3B, and fig. 3C. FIGS. 3A-3C are waveform diagrams illustrating signals associated with the operation of the memory access interface device 120 in the single data rate mode according to an embodiment of the present invention.

In more detail, in fig. 3A and 3B, waveforms of the external read enable signal EREN, the internal read enable signal IREN, and the data signal DQ are shown. In fig. 3C, waveforms of the internal read enable signal IREN, the inverted output internal read enable signal IRENV, and the data signal DQ are shown.

The following paragraphs will describe the operation of the memory access interface device 120 in the single data rate mode in more detail.

In the single data rate mode, the external read enable signal transfer circuit 210 receives the external read enable signal EREN and generates an output external read enable signal ERENO as a clock signal to drive the memory device 130 to provide a strobe function. The memory device 130 transfers the data signal DQ to the memory access interface device 120.

Meanwhile, the internal read enable signal transfer circuit 220 receives the internal read enable signal IREN and generates an output internal read enable signal IRENO. In one embodiment, the internal read enable signal IREN and the external read enable signal EREN have the same operating frequency.

In one embodiment, in the single data rate mode, the memory device 130 may operate in a first speed operating state, wherein the first speed operating state corresponds to an operating frequency that is less than a preset value. In one numerical example, the first speed operating state may correspond to an operating frequency of 10 megahertz (MHz).

In this case, since the speed is slow, the sum of the time for which the transfer of the external read enable signal ERENO, the driving of the memory device 130, and the transfer of the data signal DQ are output may be within a half period of the external read enable signal EREN as shown in fig. 3A.

Thus, as shown in FIG. 3A, the phases of the internal read enable signal IREN and the external read enable signal EREN from the memory access controller 110 are synchronized for the first speed operating state in the single data rate mode. The internal read enable signal transmitting circuit 220 generates an output internal read enable signal IRENO according to the internal read enable signal.

On the other hand, in the single data rate mode, the storage device 130 may operate in a second speed operation state, wherein the second speed operation state corresponds to an operation frequency not less than a preset value. In one numerical example, the second speed operating state may correspond to an operating frequency of 33 megahertz (MHz).

In this case, since the speed is fast, the sum of the time for the transfer of the output external read enable signal ERENO, the driving of the memory device 130, and the transfer of the data signal DQ may exceed a half period of the external read enable signal EREN as shown in fig. 3B.

Therefore, as shown in fig. 3B, in order to compensate for the signal transmission time in the high speed operation state, the phase of the internal read enable signal IREN is lagged by a half period with respect to the phase of the external read enable signal EREN in the second speed operation state of the single data rate mode. The internal read enable signal transmitting circuit 220 generates an output internal read enable signal IRENO according to the internal read enable signal.

In one embodiment, memory access interface device 120 also includes an inverter 270. The inverter 270 is configured to receive the output internal read enable signal IRENO and, as shown in fig. 3C, output an inverted output internal read enable signal IRENV.

Then, the multiplexer 250 selects the inverted output internal read enable signal IRENV as the sampling signal SS, so that the data reading circuit 240 can sample the data signal DQ.

In one embodiment, in the single data rate mode, the data reading circuit 240 may sample the data signal DQ on one of two edges of each sampling period according to the sampling signal SS to generate the read data signal RDQ. In one embodiment, the edge used to sample the data signal DQ is a falling edge, such as the falling edge shown in fig. 3C.

In another embodiment, in the single data rate mode, the data reading circuit 240 can sample the data signal DQ according to the two-wave edge, i.e. the rising edge and the falling edge, of the sampling signal SS in each sampling period. Further, the data reading circuit 240 discards a sampling result generated according to one of two wave edges (e.g., a rising edge) of the sampling signal SS to generate the read data signal RDQ.

Please refer to fig. 4. FIG. 4 is a waveform diagram illustrating signals associated with the operation of the memory access interface device 120 in the double data rate mode according to an embodiment of the present invention.

In more detail, in fig. 4, waveforms of the data strobe enable signal DSEN, the data strobe signal DQS, and the enable data strobe signal DQSE are shown.

The following paragraphs will describe the operation of the memory access interface device 120 in the double data rate mode in more detail.

In the double data rate mode, the external read enable signal transfer circuit 210 receives the external read enable signal EREN and generates an output external read enable signal ERENO to drive the memory device 130. The memory device 130 thus transfers not only the data signal DQ, but also the data strobe signal DQs to the memory access interface apparatus 120.

Meanwhile, the data strobe enable signal transfer circuit 230 receives the data strobe enable signal DSEN and generates the output data strobe enable signal DSENO.

In one embodiment, the memory access interface device 120 further includes an enable circuit 280 configured to receive the output data strobe enable signal DSENO and the data strobe signal DQS. The memory access interface device 120 is further enabled by the output data strobe enable signal DSENO to generate an enable data strobe signal DQSE.

In one embodiment, enable circuit 280 is implemented by an AND (AND) logic gate.

As shown in FIG. 4, the data strobe signal DQS may include tri-state sections TS1 and TS 2. According to the enabling of the enabling circuit 280 by using the output data strobe enable signal DSENO, a clean leading (preamble) section PR and a clean trailing (postamble) section PO corresponding to the tri-state sections TS1 and TS2, respectively, are generated at the enable data strobe signal DQSE. Such a design will avoid unstable signal drift due to process, voltage and temperature variations.

Then, the multiplexer 250 selects the enable data strobe signal DQSE as the sampling signal SS in the double data rate mode, so that the data reading circuit 240 can sample the data signal DQ. As a result of operating in the double data rate mode, the data read circuit 240 samples the data signal DQ using two edges of the data strobe signal DQSE.

It is noted that, in the above-described configuration, the edge of the inverted output internal read enable signal IRENV generated by the inverter 270 has the same relationship with the data signal DQ in the single data rate mode, as the edge of the data strobe signal DQS has with the data signal DQ in the double data rate mode. Therefore, the data reading circuit 240 can perform data sampling in the single data rate mode and the double data rate mode using the same circuit structure.

In one embodiment, the data read circuit 240 may include a read data receiving circuit 242, a read data FIFO circuit 244, and a read correction circuit 246 that operate according to, for example, but not limited to, the second divided clock signal CMDCD 2.

The read data receiving circuit 242 is configured to sample the data signal DQ according to the sampling signal SS. The read data FIFO 244 is configured to perform clock domain (clock domain) conversion on the data sampled by the read data receiving circuit 242 to generate the read data signal RDQ.

In one embodiment, the clock domain conversion is a clock domain used to convert data between the read data receive circuitry 242 and the memory access controller 110.

The read calibration circuit 246 is configured to operate on the data stored in the read data FIFO 244 according to a predetermined calibration algorithm and generate a feedback calibration signal (not shown) to the read data receiver circuit 242.

It should be noted that the above-mentioned embodiments are only examples. In other embodiments, modifications may be made by one of ordinary skill in the art without departing from the spirit of the invention.

In summary, the memory system and the memory access interface apparatus thereof of the present invention can provide the reference signal no matter in the single data rate mode or the double data rate mode to adjust the timing of the access signal, and realize the access of the memory device with accurate and adjustable timing in a low cost manner.

Although the embodiments of the present invention have been described above, these embodiments are not intended to limit the present invention, and those skilled in the art can apply variations to the technical features of the present invention according to the contents of the present invention, which are obvious or implicit, and all such variations fall within the scope of the patent protection sought by the present invention, that is, the scope of the patent protection sought by the present invention is defined by the claims of the present invention.

Description of reference numerals:

100: memory system

110: memory access controller

120: memory access interface device

130: storage device

200: clock generation circuit

210-230: access signal transmission circuit

212: phase adjustment circuit

214: duty cycle adjusting circuit

240: data reading circuit

242: read data receiving circuit

244: read data FIFO circuit

246: read correction circuit

250: multiplexer

260A: first clock frequency dividing circuit

260B: second clock frequency dividing circuit

270: reverser

280: enable circuit

CMDCD 1: first frequency-divided clock signal

CMDCD 2: second frequency-divided clock signal

CMDCLK: command reference clock signal

And (3) DSEN: data strobe enable signal

DSENO: outputting a data strobe enable signal

DQ: data signal

DQS: data strobe signal

DQSE: enabling data strobe signals

EREN: external read enable signal

ERENO: outputting an external read enable signal

ERP: phase adjusted access signal

IREN: internal read enable signal

IRENO: outputting an internal read enable signal

IRENV: inverting output internal read enable signal

PO: rear guide section

PR: leading segment

RDQ: reading data signals

RX: receiver with a plurality of receivers

And SS: sampling signal

TS 1-TS 2: three state section

TX: conveyor