JPH0444300B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] This is a self-strobe signal generation circuit that detects changing states of a plurality of tag signals corresponding to strobe signals transferred from a host device.
For example, a change in the tag signal is detected by recording the state of the tag signal in two registers using two clock signals with opposite phases, and detecting a difference between the recorded states using a comparator. The detection signal is shifted by a predetermined timing to self-generate a strobe signal, thereby making it possible to easily take in transfer data using a simple signal line.

[Industrial application field]

The present invention relates to a self-strobe signal generation circuit that self-generates a gate signal (strobe signal) for capturing data transferred from a host device through a common bus.

For example, as a method for specifying the type of data exchanged between a host device and a plurality of input/output devices comprising a computing system through a common bus, there is a method in which a tag indicating the type of data is attached to the data itself.

On the receiving side of the transferred data, the tag of the data is checked to identify the type and the appropriate processing is performed, making it possible to process different types of data even with a small number of types of instructions. However, on the other hand, the processing becomes complicated. The development of a simple processing method using such a tag method is awaited.

[Problems to be solved by conventional technology and invention]

FIG. 4 shows a system configuration diagram, and FIG. 5 shows a conventional signal output status diagram.

A plurality of modules 1(0) to 1 shown in FIG.
(n) exchanges data with the host device 2 through the common bus a. For example, data sent from host device 2 to common bus a is sent to module 1(i).
To confirm that the data is being transferred to the tag signal line b, check the change state of the tag signal sent to the tag signal line b.

Further, the data is taken in while the strobe signal sent from the host device 2 through the strobe signal line c is "on" when the tag signal is in a changing state. This situation is shown in FIG.

The tag signal line b shown in FIG. 4 consists of a plurality of signal lines, and it is possible to transfer a large number of tag signals by combining the plurality of signal lines.
Conventionally, a strobe signal signal line c dedicated to the strobe signal was required.

On the other hand, in the conventional method that does not provide a dedicated strobe signal line c, changes in the multiple tag signal lines b are limited to only one signal line at a time, and as a result, changes in the status of the tags are controlled by the module 1(i). Although the interface unit 11(i) of ) checks the data and generates a strobe signal to take in the data, there is a problem in that it is not possible to transfer many tag signals.

[Means for solving problems]

FIG. 1 shows a principle block diagram of an interface section according to the present invention.

FIG. 1 shows a change point detection section 111 that detects the change state of a plurality of tag lines TAGi by driving them with clock signals CLKA and CLKB having different phases, and a change point detection section 111 that detects the change state of a plurality of tag lines TAGi, and a change point detection section 111 that sets a predetermined state by a change in the output of the change inspection detection section 111. flip flop 112
(hereinafter referred to as F.F112), the set state output of F.F112 is shifted by a predetermined timing T4 by a shift register 113a to generate a self-strobe signal STRB having a width of the predetermined timing T4, and the module 1(i) A strobe signal generation unit 113 that outputs the
It consists of and.

[Effect]

For example, the change point detection unit 11 detects the change state of the tag signal transferred from the host device 2 through a small number of tag lines (for example, three tag lines TAG0 to TAG2).
1 to detect.

That is, the clock signals CLKA, which have opposite phases,
Drive with CLKB, record the state of the tag signal at that time, and if there is a difference in the recorded state, even if the tag signal changes, the detection signal CMP
falls.

A strobe signal is generated using this detection signal CMP.
By self-generating STRB, there is no need to provide a dedicated strobe signal line, there is no restriction on how the tag signal changes, and even if the period of change of the tag signal is not constant, the tag line Many types of data transfer are possible depending on the combination of states.

〔Example〕

The gist of the present invention will be specifically explained below with reference to embodiments shown in FIGS. 2 and 3.

FIG. 2 is a block diagram illustrating an embodiment of the present invention, and FIG. 3 is a diagram showing the operation of each signal according to the present invention. Note that the same reference numerals indicate the same objects throughout the figures.

Next, the operation of this embodiment will be explained. The embodiment shown in FIG. 2 is based on modules 1(0) to 1 shown in FIG.
1(n) is a block diagram for generating a strobe signal STRB in interface units 11(0)O to 11(n) that control the interface with the host device 2.

Further, the strobe signal STRB is used as a signal for safely receiving data sent from the host device 2 on the module 1i side. In addition, the tag signals TAR0 to TAG2 shown in Fig. 2
is from the host device 2 to each module 1(0) to 1
(n), and the control content is displayed by a combination of three tag signals TAR0 to TAG2.

Furthermore, the clocks CLKA, CLKB, and CLK1 are signals generated internally in the module 1(i), and in particular, the clocks CLKA and CLKB are clock signals having opposite phases to each other as shown in FIG.

Each module 1 (0) to 1 from the host device 2
Tag signal TAR0~ sent to (n)
TAG2 are sent out almost simultaneously, but arrive at the interface section 11(i) with a maximum variation of T1 due to the influence of the distributed capacitance of each tag line.

The register 111a is driven by the clock CLKA and stores the changing state of the tag signals TAR0 to TAG2, and the register 111b is driven by the clock CLKB and stored. Further, the contents stored in the register 111a and the register 111b are stored in the comparison circuit 111c.
If there is a difference, the predetermined signal CMP is dropped. Note that if the contents are the same, the signal output will not change.

The fact that the contents stored in the register 111a and register 111b are different means that the tag signal TAR
0 - Indicates that there has been a change in the state of TAG2.
That is, this indicates that there is data transmission on the common bus a, and that a predetermined control signal is accordingly transmitted from the tag signals TAR0 to TAG2.

F.F112 activates the set shift register 113a based on a change in the predetermined signal CMP output from the comparison circuit 111c. When a predetermined period of time has elapsed after starting the shift register 113a, a predetermined signal is sent to one input terminal of the AND circuit 113c,
As a result, the strobe signal STRB turns "on", continues for a time T4, and then turns "off" by sending a predetermined signal to the input terminal side of the inverter 113b.
becomes.

F.F112 and shift register 113a change the output side of inverter 113b (i.e., "ON").
It is reset by "off") and ready for the next operation.

Note that the time it takes for the strobe signal STRB to turn “on” is the fastest among the changes in the tag signals TAR0 to TAG2 (in Figure 3, the time required for the strobe signal STRB to turn “on” is
0) after T2 hours have elapsed, and T2>>T
It is set as 1.

In addition, the minimum period of change of the tag signals TAR0 to TAG2, that is, the period T3 from the change point of the tag signal TAR1 to the next change point of the tag signal TAR0 in FIG.
It is assumed that T3>T4 is set.

As described above, since the strobe signal STRB is generated by itself by detecting the changing state of the tag signals TARO to TAG2 transferred from the host device 2, it is not necessary to provide a dedicated strobe signal line.

〔Effect of the invention〕

According to the present invention as described above, the tag signal can be controlled without providing a dedicated strobe signal line, without placing any restrictions on the method of changing the tag signal, and even if the period of change of the tag signal is not constant. This has the effect of allowing many types of data transfer determined by combinations of tag line states.

[Brief explanation of drawings]

FIG. 1 is a principle block diagram of the interface section according to the present invention, FIG. 2 is a block diagram explaining an embodiment of the present invention, FIG. 3 is an operation diagram of each signal according to the present invention, and FIG. 4 is a system diagram. A configuration diagram and FIG. 5 show a conventional signal output situation diagram, respectively. In Figures 2 and 4, 1(0) to 1(n) are modules, 11(0)
11(n) is an interface section, 111 is a change point detection section, 112 is an FF, 113 is a strobe signal generation section, 111a and 111b are registers, 11
1c is a comparison circuit, 113a is a shift register, 1
13b is an inverter, 113c is an AND circuit, 2
indicate the upper-level device, respectively.

Claims (1)

[Scope of Claims] 1. In a device in which a host device and a plurality of modules are connected via a common bus, and each of the modules uses the common bus as a common data transfer path, the interface unit 11 of the module ( i) records the changing states of a plurality of TAB signals sent from the host device in a plurality of registers 111a and 111b using a plurality of clock signals (CLKA, CLKB) having mutually different phases; a tag change point detection section 111 that detects the change state of the plurality of tag signals by detecting the difference between the states of the plurality of registers 111a and 111b in a comparison circuit 111c; A flip-flop 112 that sets and holds the flip-flop 112 upon the first change; and a shift register 1 that takes in the output of the flip-flop 112 at a predetermined clock CLK1, shifts it by a predetermined timing T4, and outputs it.
13a to generate a strobe signal having the shift width of the shift register 113a, a strobe signal generating section 113 is provided, and the changing state of the plurality of tag signals is detected by the tag change point detecting section 111, and the above-mentioned The first change in the detection signal detected by the tag change point detection unit 111 is set and held in the flip-flop 112;
Self-strobe signal generation characterized in that the output of the held flip-flop 112 is input to the strobe signal generation section 113 to generate a stove signal with a predetermined width T4 and to take in data from the common bus. circuit.