TWI376890B - Method for generating a spread spectrum clock and apparatus thereof - Google Patents

Description

1376890 VI. Description of the Invention: [Technical Field] The present invention relates to a method for generating and displaying a pulse, and a related display thereof, and more particularly to a method for determining a time point of a spread frequency clock switching frequency generated With the device. [Prior Art] The clock circuit is a far-reaching influence on the overall performance of the most important components of the electronic device. However, the clock signal produces a strong electromagnetic interference (EMI) at its frequency. Usually a threshold value is defined and the electromagnetic interference of the desired clock signal falls below this threshold. Therefore, 'the frequency of the clock signal is dynamically changed so that the energy of the clock signal is dispersed to different frequencies, and the prison is called a slit clock generation. [Invention] The object of the present invention It is to provide a method of generating a spread-spectrum clock and its farming to solve the problems in the prior art. Step mrr reveals a method of generating a spread spectrum clock. The method includes a reference clock having a reference period; a clock according to the Γ=Γ; according to the reference clock and the spread frequency clock production = 'two starts a first period; In the first period, according to the first-selection signal, it represents the first-first-order order; in the first period_pulse==, the _th of the first-predetermined order, the output of the different phases is outputted as the target Spreading the clock; according to the reference clock and the spread frequency control signal 'and start a second period; in the second period, according to the 5th second control signal output - the second selection signal, which represents a a second predetermined sequence, the fifth predetermined second order is substantially opposite to the first predetermined order; and in the second period, the second selected position and the second predetermined order are outputted according to the second (four) pulse A plurality of 'as the spread spectrum clock. Embodiments of the present invention further disclose a spread spectrum clock generating apparatus for generating a spread spectrum clock based on a reference clock. The spread spectrum clock generation module includes: - the control signal generation "is used to control the signal and the second control signal according to the lion reference clock and the exhibition, and correspondingly start a period - a period a second period; a selection of the signal generator 'in the first period _, according to the first control number output representative of the first-predetermined order selection signal, and in the second _, according to the second control signal output representative a second predetermined sequence of second selection signals, wherein the second predetermined sequence is substantially opposite to the first predetermined sequence; a multi-phase clock generator for generating a plurality of output clocks having different phases according to the reference clock; And a selector for rotating the plurality of phases 1376890 and the output timing pulse in the predetermined period according to the first predetermined period of the first selection signal as the spread frequency clock, and In the second period, the second predetermined sequence of the second selection signals is outputted as the plurality of output clocks having different phases as the spread-up clock. [Embodiment] FIG. 1 is a schematic view showing an embodiment of a brain of a spread spectrum clock generating apparatus of the present invention. As shown in Fig. ι, the spread spectrum clock generating device i(8) includes a reference clock generating module ιι〇 and a spread frequency clock generating touch UO. The reference clock generation remainder 11G provides a reference clock CLKref having a reference period TREF, and the spread spectrum clock generation module 12 is used to generate the pulse CLKss according to the reference clock CLKr^. The development of the pulse product includes a judgment and control unit (10) and a period setting unit (10), wherein the judgment and control is earlier than 13 (H is based on the difference between the reference clock CLKref and the spread frequency clock CLKss to generate a first selection signal SEL1 Or the second selection signal SEL2, thereby indicating that the period setting unit 140 is switched from the period D1 to the period D2 or vice versa. In the embodiment, the determination point control unit 130 performs the period m when the reference CLKref is substantially different from the sheet CLKss by W2. The switching of D2 is performed to achieve a better spread spectrum effect. The period setting unit M0 provides the spread spectrum with the second average period τ2 of the -first-average period m according to the selection signal SEL1 and the fox 2 for the period cut and the 〇2, respectively. Clock CLKSS. Please note that 'the implementation of the test time CL1Wu is equal to 50%, but the invention is not limited to this. ' Figure 2 (including Figure 2A and Figure 2B) is the first! Shows the spread-frequency clock (10) 6 1376890's not intended 'where Figure 2 is from the cycle 2 a delay time. Therefore, the spread-spectrum clock CLKss during the period, the average period of the test period Tref (four) (such as the left side of the dotted line = there is ^ Ref = the average period T2 of the reference period TREF (such as the right side In carrying out the invention in light of the disclosure of the present specification, one skilled in the art can design a total super-time (or period 2) and corresponding circuitry to implement the present invention, as long as the period: 'phase'. Period Τ1 and various average weeks = map shows, set the frequency of the spread frequency clock ^, because

; CLKss "I recorded), and in __, exhibit (four) pulse in the average period T2 of the corresponding frequency (four) (ie (10). So - come, because the frequency of ZCLKSS is not concentrated on a single frequency, so the dispersion energy can be achieved In addition, in order to prevent the frequency of the spread spectrum clock CLKss from being too fast or slow compared to the frequency of the spring test, the data output rate (data th_ghput) before and after the spread spectrum is inconsistent, This embodiment sets the period_equal to 'to prevent this phenomenon', but this is not a limitation of the present invention, as long as the period (or phase) is equal to the total lead time (or phase) accumulated in the period D2. , to prevent this phenomenon.夂 Fig. 3 is a schematic diagram of an example of the judgment and control unit 13 of Fig. 1. As number 7

Ttotal + step 6n., the total delay time can be expressed by the total delay phase.乂·= in the second period, 'set the spread spectrum_has—the second period, i step 606, the second period is less than the reference period, and the cumulative total lead time is the parent period and each reference period The cumulative total of differences) is also T_ 'this total delay time can be expressed by the total delay phase. Returning to Step 1: The steps shown in the figure can be performed by using the components shown in Figures 3 or 5 and 4, and the step 608 is performed by the judgment and control unit 13〇, and the steps (10) to 612 are performed. It is executed by the cycle setting unit (10). Please refer to the detailed operation of each component.

Figure 7 is a schematic diagram of an embodiment of the spread spectrum clock generating device 7GG of the present invention, the architecture of the device 700 and the first! The device of the figure is similar, and the differences between the two are described below. In Fig. 7, the 'judgment and control unit, (for example, finite state machine, coffee machine), according to the reference pulse CLKref, the spread spectrum clock CLKss, and a phase sustain signal PH1 to generate the selection signal SEU, arc 2 Or SEU decides to switch to period D Bu D2 4 D3 'where phase maintaining signal PH1 is a timing signal for indicating whether a predetermined time has been reached. In this embodiment, during the period D1, if CL

When SS lags CLKREF to TREF/2, it switches from D1 to D3. When phase hold signal PH1 indicates that D1 switches to D3 for the predetermined time, it switches from D3 to d2. When switching to D2, if CLKSS leads CLKREF. When TREF/2 is reached, it is switched from D2 to D3; when the phase maintenance signal PH1 indicates that D2 is switched to D3 for the predetermined time, the inspection 740 is in the period of the sound map H (including FIG. 8A and FIG. 8B) as the seventh diagram. The exhibition _ _ _ _ _ 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 ~Τ2,". As shown in the figure, the frequency of CLl/like % is f'. Therefore, during the period m, still and D2, the frequencies of the spread spectrum SS are fl (ie f - d ), β (ie f) and β ( That is, f + d ). Here, she is shown in Fig. 2, this embodiment can further spread the frequency at the time of spreading to achieve the purpose of dispersing energy and reducing electromagnetic interference. In addition, in the example, the total delay time (or phase) accumulated during the period D1 is equal to the total lead time (or phase) of the period m ^ accumulation, so as to prevent the data output rate before and after the spread spectrum from being different from the month to the month. The 'described embodiment' describes the situation of two and three periods, respectively. However, those skilled in the art can use the three inventions in accordance with the disclosure of the present invention. Heart Test Figure 9 '9th ® is the method of generating a spread-spectrum clock for the present invention. 4 I&Uiil' is different from the flow chart shown in Figure 6 in the following steps: 12 1376890: Step 91〇:== pulse, the spread spectrum clock, and a phase sustain signal to determine. == period, the second period, and the third period, wherein the phase i92〇: in the = three period, the spread spectrum is set The clock has a third period, and the third period is equal to the reference period. Go back to the steps. And the implementation of the above steps ^ and 7820 can use the judgment and control unit of Figure 7 - this does not repeat = early realization 'The detailed operation of these units, please refer to the above, in the case of the example of riding the branch (4) Under the implementation of the line, the explicit conditions 'and the steps that do not violate the spirit of the present invention: appropriate = his intermediate step can be combined into several steps - the proud of the 1 is the handle of her real paste, where According to the (4) cap patent range, the average (4) tilting modification is based on the invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a first embodiment of a spread spectrum clock generating apparatus of the present invention. Fig. 2 (including Fig. 2A and Fig. 2B) is a schematic diagram of the spread spectrum clock shown in Fig. 1.丄:)/Οδβυ • Fig. 3 is a schematic diagram of an embodiment of the judgment and control of the first figure. The diagram is a schematic diagram of the -$! example of the cycle setting unit of Fig. 1. Fig. 5 is a view showing another embodiment of the judgment and control unit of Fig. 1. Lu 6 shows a flow chart of an operation example of a method for generating a spread spectrum clock according to the present invention. Figure 7 is a schematic view showing a second embodiment of the spread spectrum clock generating apparatus of the present invention. Fig. 8 (including Fig. 8A and Fig. 8A) is a schematic diagram of the spread spectrum clock shown in Fig. 7. Figure 9 is a flow chart showing another example of the operation of the method for generating a spread spectrum clock according to the present invention. ▲ [Main component symbol description] 100, 700 spread spectrum clock generation device 110 reference clock generation module 120, 720 spread spectrum clock generation module 130, 730 judgment and control unit 140, 740 cycle setting unit CLKREf reference clock CLKSS spread spectrum clock 1376890

Tref reference period Ή, T2, T3 averaging period m, D2, D3 period f, Ω, f2, β frequency d difference Td delay time 310 judgment circuit 320 control signal generator 340 selects signal generator DR judgment result SCI, SC2 SC control signal SEU, SEL2, SEL3 select signal CNT count signal 410 multi-phase clock generator 420 selector 430 multiplexer DL1 ~ DLn delay CK1 ~ CKn output clock 510 oscillator 520, 540 counter 530 finite state machine 532 Operation circuit CN1 Oscillator count value 15 1376890 CN2 Reference clock count value CN3 Spread spectrum clock count value 602~612, 910, 920 Step PH1 Phase maintenance signal

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Claims (1)

1376890 VII. Patent application scope: The method of spreading spread frequency clock (providing a reference clock with one reference period); and including: generating a spread spectrum clock according to the reference clock, The method includes: generating a plurality of outputs having different phases according to the reference clock, and referring to the clock and the generating a first period: in the first period, according to the first control The signal outputs a first selection signal, and the first selection signal represents a first predetermined sequence; During the first period, a plurality of the output clocks having different phases are sequentially rotated according to the first predetermined sequence of the first selection signal, and the _ frequency clock is used according to the reference clock. The spread spectrum clock generates a second control signal, and correspondingly starts a second period; ^ during the first period, 'outputs a second selected ton according to the second control signal; f' The second predetermined order is based on a plurality of output clocks having different phases to serve as the orbit. 2. The method of claim 1, wherein the output of the output period of the output clock is outputted by the output clock corresponding to one of the output clocks. ^ bit. 3. The street described in item 1 of the side, (4) _- and/or the second step of the signal consisting of: - step control determines whether the first edge of one of the reference clocks corresponds to one of the spread spectrum clocks Second, the edge produces a judgment result, wherein the first edge and the second edge respectively have a JE edge and a negative edge or a negative edge and a positive edge; and the Tianyuan judgment result indicates that the first edge corresponds to The second edge generates the second/first control signal from the state of the first period/second period, and starts the second/first period relative to the library. The method of claim 3, wherein the working period of the reference clock is equal to 50 ο/ρ. 5. The method of claim 1, wherein the method further comprises: And the Lai clock generates a third control ship number, and correspondingly starts a third period; in the third_, according to the third control, the n selection signal #•和~' During the period, at least one of the reference clocks and the rounded clocks different from the phases are outputted according to the third selection signal as the material of the step. The method of claim 5, further comprising: generating a first or second control signal according to a timing signal during a second period, and correspondingly starting the first Or the second period. A method for generating a spread spectrum clock (spreadspectrunid 〇ck) includes: providing a reference clock having a reference period; and generating a spread spectrum clock according to the reference clock, including: according to the reference The pulse generates a plurality of round-trip clocks having different phases; generating a first control signal according to the 4-number signal, and correspondingly starting - the first period; in the second period, according to the brother-control signal outputting a selection signal, the first selection signal represents a first predetermined sequence; in the "first period", according to the first apology sequence of the first selection signal, sequentially outputting a plurality of output clocks having different phases, As the spread spectrum clock; And generating a first control signal according to the counting signal, and correspondingly starting a second period; and during the second period, outputting a second selection signal according to the second control signal. The second selection signal represents a first box-order sequence, the first-order and the first-predetermined sequence are mixed, and the predetermined Chuanbei is in the second_inner (four) quality 4th order reverse; and the sequence is different from the phases ; choose to reduce the frequency of the clock to a pre-order. A plurality of the clocks are read as the method of the present invention, which is described in claim 7, wherein the method of claim 7 wherein the cumulative delay phase corresponds to the cumulative delay phase is substantially equal to the material 2 One of the output clocks outputted therein accumulates the leading phase. ζ一··9· The method of claim 7, wherein the method further comprises: generating a third control signal according to the ^counting signal, and correspondingly starting - the third period is in the third_inner According to the third control signal output-the third selection signal and the u-person 1〇. The spread-spectrum clock generation device includes: One reference clock; a reference clock generation module' provides a reference period and a spread spectrum clock generation module, and is connected to the reference clock generation module for generating according to the reference clock - The spread spectrum clock generation module includes a wide-ranging judgment and control unit, and includes: control. The fU tiger generator is configured to generate a first control signal according to the reference clock and the spread spectrum clock, and correspondingly start a first period, and generate a first according to the reference clock and the spread frequency clock a second control signal, and correspondingly starting a second period; and 20 a selection signal generator for outputting a -selection signal according to the first control signal during the first period, the first selection signal representative a first predetermined sequence, and in the second period, according to the second control signal output-second selection signal, the second selection signal represents a second predetermined sequence, the second predetermined sequence and the first predetermined sequence Substantially opposite; and a period setting unit, comprising: a multi-phase clock generating H, the county according to the Wei reference Wei generating a plurality of output clocks having different phases; selecting 'for the first period, according to the The first-predetermined sequence of the first selection signal sequentially outputs a plurality of the different output clocks of the plurality of selection signals as the spread-time clock, and in the second period The optional second predetermined sequence of signals sequentially output the plurality of outputs of different phases of a plurality of veins, as to the spread spectrum clock. The apparatus of claim 10, wherein the selected one of the output clocks outputted in the first period gate has a cumulative delay phase substantially equal to that in the first period One of the output clocks corresponding to the output accumulates the leading phase 0, wherein the judging and controlling unit further includes: as described in claim 1 of the patent scope: 21 judging circuit 'for repaying the reference Whether the first edge of the pulse corresponds to the edge of the _%· pulse to generate a judgment result, wherein the first edge and the first edge of the basin are a positive edge and a negative edge or a negative edge respectively And a positive edge; wherein 'when the judgment result of the judgment circuit indicates that the first edge corresponds to the second edge, the control signal generator is in the state of the first period/second period, - Control signal 'and correspondingly start the second/first period. 13. The device of claim 12, wherein the reference clock has a working period equal to 50%. K is the device described in the Japanese Patent Application (4), wherein the control signal generator is additionally used to generate a third control according to the fresh tree vein and the secret vein, and correspondingly start the $2 period; The selection signal generating unit is further configured to output the third control signal according to the third control signal during the third period; and the selector is further configured to output the signal according to the third selection signal during the third period The reference clock is at least one of the different (four) pulses different from the phases, as the spread spectrum clock. ' 15. If the application is as described in item 14, the control signal generator is additionally used to generate the first or second control signal according to the timing signal during the third period. The first or second period is started correspondingly. 16. A spread spectrum clock generating apparatus comprising: 22 j37689 〇 reference clock generation module for providing a reference clock having a reference period; and a 'spreading frequency clock generation group' The reference clock generation surface is configured to generate and display a pulse according to the reference clock. The spread spectrum clock generation module includes “a judgment and control unit, including: a control signal generator for generating a first control signal according to a counting signal and correspondingly starting a first period, and generating a second control signal according to the counting signal, and correspondingly starting a second room And a selection signal generator for outputting the first-selection signal according to the first-control signal output-first selection signal in the first__, and in the second period _ According to the second control signal output-second selection signal, the second selection signal represents a first The second predetermined sequence 'the second predetermined order is opposite to the first-order sequence; and the negative one-time setting unit includes: - multi-phase miscellaneous generation n, and the number of the nano-scales is different. The round of the phase of the phase; and the selection of the 'for the first period', according to the first selection signal, the first predetermined order of the first selection signal sequentially outputs the recurring texts of the different rounds of the phase And as the spread frequency clock, and in the second period, the plurality of output clocks of the second snack according to the second selection signal are different according to the phase 4, as the spread frequency 23 Clock. Such as the device described in claim 16 of the 5th patent scope, The device according to claim 16, wherein the control signal generator further includes the selector in the first phase of the cumulative delay phase. Substantially generating a third control signal according to the counting signal, and correspondingly starting a second period; the selecting signal generating unit is further configured to output a second according to the second control signal during the third period a third selection signal; and the selector is further configured to: during the third period, output at least one of the reference clocks different from the phases according to the second selection signal as the spread spectrum pulse. Eight, round: 24