JPH01205647A - Serial communication system - Google Patents

Serial communication system

Info

Publication number
JPH01205647A
JPH01205647A JP63030344A JP3034488A JPH01205647A JP H01205647 A JPH01205647 A JP H01205647A JP 63030344 A JP63030344 A JP 63030344A JP 3034488 A JP3034488 A JP 3034488A JP H01205647 A JPH01205647 A JP H01205647A
Authority
JP
Japan
Prior art keywords
line
data
busy line
busy
transmission
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP63030344A
Other languages
Japanese (ja)
Other versions
JPH0683291B2 (en
Inventor
Shigeo Niitsu
新津 茂夫
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to JP63030344A priority Critical patent/JPH0683291B2/en
Publication of JPH01205647A publication Critical patent/JPH01205647A/en
Publication of JPH0683291B2 publication Critical patent/JPH0683291B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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  • Communication Control (AREA)

Abstract

PURPOSE:To attain very high speed communication by multiplexing a confirmation ACK output from a reception IC to a transmission IC having been on a data line in a conventional system onto a busy line controlling the start and stop. CONSTITUTION:When a reception side IC2 receives a data D1-D0 sent from a transmission side, an ACK output representing the reception is outputted to the same busy line 33 in the timing of t1-t4. Since the busy line 33 is of wired OR constitution depending on the open drain structure, even if a busy line drive 4 at the sender side is reset, the bus line is fixed to a low level. Thus, the busy line drive 4 is reset at the transmission side in the timing of t2-t3 shorter than the t1-t4 to apply acknowledgment 38. The ACK output is driven on the busy line in this way, since the drive impedance is lowered even with a capacity added thereto, then high speed data transmission is attained.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明はシリアル通信方式に関し、特にIC間のデータ
の授受を行うシリアル通信方式に関する。
DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a serial communication system, and particularly to a serial communication system for exchanging data between ICs.

〔従来の技術〕[Conventional technology]

従来、この種のシリアル通信において送信側から受信側
に送ったデータに対して受信側がら送信側に返送するア
クノレッジ信号(以下、AcX:信号)はデータライン
を共用したり、専用のラインを用いて返送するのが一般
的となっていた。
Conventionally, in this type of serial communication, the acknowledgment signal (hereinafter referred to as AcX) sent back from the receiving side to the transmitting side for data sent from the transmitting side to the receiving side has been transmitted by sharing a data line or using a dedicated line. It was common practice to send them back.

例えば第2図に示すように、データライン202で送信
側より受信側へ送ったデータに対して同じデータライン
203で受信側より送信側へアクティブロウのACK信
号203a部を送信側へ返送する。ここに202と20
3は同一ラインであり、又ライントライバ回路はオープ
ンドレイン構造である。このためデータラインはワイヤ
ードオア接続可能となっている。
For example, as shown in FIG. 2, for data sent from the transmitting side to the receiving side on a data line 202, an active low ACK signal 203a portion is returned from the receiving side to the transmitting side on the same data line 203. 202 and 20 here
3 are the same line, and the line driver circuit has an open drain structure. For this reason, the data line can be wired or connected.

〔発明が解決しようとする課題〕[Problem to be solved by the invention]

しかしながら、上述した従来のシリアル通信方式ではデ
ータラインを共用しているため、データラインをドライ
ブする送信又は受信ICの構造はプッシュプル構造をと
ることができず、オープンドレイン構造にならざるをえ
なかった。このため、高速のデータを転送しようとする
と波形がなまってしまい、高速転送に問題があった。ま
た、バスの切り換えを短時間で行なわなければならず、
この面からも高速転送に適さないという欠点がある。
However, in the conventional serial communication method described above, since the data line is shared, the structure of the transmitter or receiver IC that drives the data line cannot have a push-pull structure, and must have an open-drain structure. Ta. For this reason, when attempting to transfer high-speed data, the waveform becomes dull, which poses a problem in high-speed transfer. In addition, bus switching must be done in a short period of time,
From this point of view as well, it has the disadvantage of not being suitable for high-speed transfer.

〔課題を解決するための手段〕[Means to solve the problem]

本発明のシリアル通信方式は、少くとも2個の通信回路
の間を、データを転送するデータラインと、前記データ
のビット系列に同期したクロックを送出するクロックラ
イ、ンと、送信のスタートとストップをコントロールし
プルアップ抵抗(又はプルダウン抵抗)により第1の論
理レベルに固定されているビジーラインとで相互接続し
、データを受信した受信側がACK確認をするためある
特定の期間、前記ビジーラインを第2の論理レベルとし
、送信側がこれを確認するときに前記タイミングより短
いタイミングで出力を解放し、このラインの状態を読む
ことにより、受信側のACK確認を受け取るように構成
される。
The serial communication system of the present invention connects at least two communication circuits with a data line for transferring data, a clock line for sending out a clock synchronized with the bit sequence of the data, and a start and stop of transmission. is interconnected with a busy line that is controlled and fixed at the first logic level by a pull-up resistor (or pull-down resistor), and the receiving side that has received the data keeps the busy line open for a certain period of time in order to confirm the ACK. The second logic level is set, and when the transmitting side confirms this, the output is released at a timing shorter than the above timing, and the ACK confirmation from the receiving side is received by reading the state of this line.

〔実施例〕〔Example〕

次に、本発明の実施例について図面を参照して説明する
Next, embodiments of the present invention will be described with reference to the drawings.

第1図は本発明の一実施例である通信網の回路図である
。第1図に示すように通信回路IC+及びICzはクロ
ックラインlとデータライン2とビジーライン3とに並
列に接続される。ビジーライン3にはプルアップ抵抗R
1を介して電源VDDに接続される。それぞれの通信回
路IC+及びIC2は、ビジーライン3に接続される出
力駆動回路4及び入力回路5と、送受信制御部6とを備
える。
FIG. 1 is a circuit diagram of a communication network that is an embodiment of the present invention. As shown in FIG. 1, communication circuits IC+ and ICz are connected in parallel to clock line 1, data line 2, and busy line 3. Busy line 3 has a pull-up resistor R
1 to the power supply VDD. Each of the communication circuits IC+ and IC2 includes an output drive circuit 4 and an input circuit 5 connected to the busy line 3, and a transmission/reception control section 6.

IC+を送信側、IC2を受信側とすると、IC+の送
受信制御部6により先ず出力駆動回路4を通してビジー
ライン3をロウレベルに落とし送信を開始し始める。次
にクロックライン1.データライン2を駆動し、クロッ
ク及びデータIC2へ送信する。IC2はこのクロック
及びデータを受信し、送受信制御部6により解読し1バ
イトデータの終りにIC,の出力駆動回路4でロウレベ
ルに引っばっているビジーライン3をさらにIC2の出
力駆動回路4によりACK出力としてさらにロウレベル
に引っばる。送信側のIC,が受信側IC。
Assuming that IC+ is on the transmitting side and IC2 is on the receiving side, the transmission/reception control unit 6 of IC+ first lowers the busy line 3 to a low level through the output drive circuit 4 and starts transmission. Next, clock line 1. Drives data line 2 and sends clock and data to IC2. The IC2 receives this clock and data, decodes it by the transmission/reception control unit 6, and at the end of the 1-byte data, the output drive circuit 4 of the IC 2 ACKs the busy line 3 pulled to low level by the output drive circuit 4 of the IC2. The output is further pulled to a low level. The sending IC is the receiving IC.

のACK出力を確認するにはIC,の出力駆動回路なハ
イインピーダンス(Hi−Z状態)にして、入力回路5
によって確認することができる。
To check the ACK output of the IC, set the output drive circuit of the IC to high impedance (Hi-Z state) and connect the input circuit 5.
It can be confirmed by

第3図は第1図の通信網の動作を説明するための各ライ
ンの論理レベルのタイミング図である。
FIG. 3 is a timing diagram of the logic levels of each line for explaining the operation of the communication network of FIG. 1.

以下、第1図の通信網の動作について第3図を参照して
説明する。第3図において、スタート34を送信側IC
,がビジーライン34をロウレベルに引っばることによ
りおこなう。この後、クロックライン31及びデータラ
イン32にクロック及びデータをのせて送信する。受信
側ICzは送信側より送られてきたD1〜D0のデータ
を受信すると、受信したというACK出力37をA1〜
A4のタイミングで同じビジーライン33に出力する。
The operation of the communication network shown in FIG. 1 will be explained below with reference to FIG. 3. In Fig. 3, the start 34 is connected to the transmitter IC.
, by pulling the busy line 34 to a low level. Thereafter, a clock and data are placed on the clock line 31 and data line 32 and transmitted. When the receiving side ICz receives the data D1 to D0 sent from the transmitting side, it sends an ACK output 37 indicating that it has been received to A1 to D0.
It is output to the same busy line 33 at the timing of A4.

このビジーライン33はオープンドレイン構造によるワ
イヤードオア構成となっているため、もし、この期間送
信側のビジーラインドライブ4をOFFしてもパスライ
ンはロウレベルに固定されているはずである。このため
At〜A4より短いA2〜A3のタイミングで送信側の
ビジーラインドライブ4を0FFLACK確認38をお
こなう。
Since this busy line 33 has a wired-OR configuration with an open drain structure, even if the busy line drive 4 on the transmitting side is turned off during this period, the pass line should be fixed at a low level. For this reason, the 0FFLACK confirmation 38 of the busy line drive 4 on the transmitting side is performed at the timing of A2 to A3, which is shorter than At to A4.

このように、ACK出力なビジーラインにのせたことに
より、データラインを双方向で用いる必要がなく、クロ
ックライン、データラインを送信側においてプッシュプ
ル形式で駆動することにより、容量が付加されても駆動
インピーダンスを低くできるため高速なデータの転送が
可能となる。
In this way, by placing the ACK output on the busy line, there is no need to use the data line in both directions, and by driving the clock line and data line in a push-pull format on the transmitting side, even if capacitance is added. Since drive impedance can be lowered, high-speed data transfer is possible.

−例を示すると、駆動インピーダンスが300Ωで配線
容量が1000pFついても0.2μsの波形遅れしか
生じない。又、非常に高速に転送をおこなうためにAC
K確認38を1時中断する場合にはいつもロウレベルに
引っばっておけば、バスとしてはACKを確認したこと
になり、高速転送にも対応できる。又、送信側がACK
確認をしようとHi−Z状態にしたときACK出力が出
ていなかったときは、ビジーラインはハイレベルになる
。これはストップと同じであり自動的にバスを中断する
ことができる。
- To give an example, even if the drive impedance is 300Ω and the wiring capacitance is 1000 pF, only a waveform delay of 0.2 μs occurs. Also, in order to transfer at very high speed, AC
If the K confirmation 38 is temporarily interrupted, if it is always pulled to a low level, the bus will confirm the ACK, and can support high-speed transfer. Also, the sending side ACKs
If the ACK output is not output when the state is set to Hi-Z for confirmation, the busy line becomes high level. This is the same as stop and can automatically interrupt the bus.

〔発明の効果〕〔Effect of the invention〕

以上説明したように本発明のシリアル通信方式は、従来
データラインにのせていた受信ICから送信ICへのA
CK確認出力をスタート、ストップを制御するビジーラ
インに多重化することによりデータラインを高速で制御
できることができ、極めて高速な通信を可能とすること
ができるという効果がある。
As explained above, the serial communication system of the present invention allows A
By multiplexing the CK confirmation output to the busy line that controls start and stop, the data line can be controlled at high speed, and there is an effect that extremely high-speed communication can be made possible.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本発明の一実施例を用いる通信網の回路図、第
2図は従来の通信網のデータ転送の説明図、第3図は本
発明の通信網のデータ転送の動作を説明するために各ラ
インの論理レベルのタイミング図である。 ■・・・・・・クロックランイン、2・・・・・・デー
タライン、3・・・・・・ビジーライン、4・・・・・
・出力駆動回路、5・・・・・・入力回路、6・・・・
・・送受信制御部、31・・・・・・クロックライン(
送信側)、32・・・・・・データライン(送信側)、
33・・・・・・ビジーライン(送信側)、34・・・
・・・ビジーライン(受信側)、35・旧・・スタート
、36・・・・・・ストップ、37・・・・・・ACK
出力、38・・・・・・ACKR認。 代理人 弁理士  内 原   晋
Fig. 1 is a circuit diagram of a communication network using an embodiment of the present invention, Fig. 2 is an explanatory diagram of data transfer in a conventional communication network, and Fig. 3 is an explanation of data transfer operation in the communication network of the present invention. This is a timing diagram of the logic levels of each line. ■...Clock run-in, 2...Data line, 3...Busy line, 4...
・Output drive circuit, 5... Input circuit, 6...
...Transmission/reception control unit, 31...Clock line (
transmission side), 32...data line (transmission side),
33... Busy line (sending side), 34...
・・・Busy line (receiving side), 35・old・start, 36・・・・stop, 37・・・・ACK
Output, 38...ACKR acknowledged. Agent Patent Attorney Susumu Uchihara

Claims (1)

【特許請求の範囲】[Claims] 少くとも2つの通信局間を、データを転送するデータラ
インと、前記データのビット系列に同期したクロックを
送出するクロックラインと、送信のスタートとストップ
をコントロールするビジーラインとで相互接続し、デー
タの受信局側はデータの送信局側へデータを受信したこ
とを示すアクノレッジ信号を前記ビジーライン上に出力
し、前記送信局側は前記アクノレッジ信号の出力期間よ
り短い期間の間前記ビジーラインのレベルを検出するこ
とで前記アクノレッジ信号を受け取ることを特徴とする
シリアル通信方式。
At least two communication stations are interconnected by a data line for transferring data, a clock line for sending out a clock synchronized with the bit sequence of the data, and a busy line for controlling the start and stop of transmission. The receiving station side outputs an acknowledge signal to the data transmitting station side on the busy line indicating that data has been received, and the transmitting station side maintains the level of the busy line for a period shorter than the output period of the acknowledge signal. A serial communication method characterized in that the acknowledge signal is received by detecting.
JP63030344A 1988-02-12 1988-02-12 Serial communication method Expired - Fee Related JPH0683291B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP63030344A JPH0683291B2 (en) 1988-02-12 1988-02-12 Serial communication method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP63030344A JPH0683291B2 (en) 1988-02-12 1988-02-12 Serial communication method

Publications (2)

Publication Number Publication Date
JPH01205647A true JPH01205647A (en) 1989-08-18
JPH0683291B2 JPH0683291B2 (en) 1994-10-19

Family

ID=12301220

Family Applications (1)

Application Number Title Priority Date Filing Date
JP63030344A Expired - Fee Related JPH0683291B2 (en) 1988-02-12 1988-02-12 Serial communication method

Country Status (1)

Country Link
JP (1) JPH0683291B2 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5341380A (en) * 1992-03-19 1994-08-23 Nec Corporation Large-scale integrated circuit device
JP2001274862A (en) * 2000-02-22 2001-10-05 Thomson Multimedia Sa Method for serially transmitting data between two electronic bus stations and bus station used by the method
JP2007179637A (en) * 2005-12-27 2007-07-12 Kenwood Corp Recorder and/or reproducer, controller and control method

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5341380A (en) * 1992-03-19 1994-08-23 Nec Corporation Large-scale integrated circuit device
JP2001274862A (en) * 2000-02-22 2001-10-05 Thomson Multimedia Sa Method for serially transmitting data between two electronic bus stations and bus station used by the method
JP4565459B2 (en) * 2000-02-22 2010-10-20 トムソン マルチメディア Method for serial transmission of data between two electronic bus stations and bus station used in the method
JP2007179637A (en) * 2005-12-27 2007-07-12 Kenwood Corp Recorder and/or reproducer, controller and control method
JP4702046B2 (en) * 2005-12-27 2011-06-15 株式会社ケンウッド Recording and / or reproducing device, control device and control method

Also Published As

Publication number Publication date
JPH0683291B2 (en) 1994-10-19

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