外文翻譯---錯誤處理

1、<p><b>　　附 錄：</b></p><p>　　ERROR HANDLING</p><p>　　Error Detection：</p><p>　　There are 5 different error types (which are not mutually exclusive)：</p><p&

2、gt;　　BIT ERROR：</p><p>　　A unit that is sending a bit on the bus also monitors the bus. A BIT ERROR has to be detected at that bit time， when the bit value that is monitored is different from the bit value t

3、hat is sent. An exception is the sending of a “recessive” bit during the stuffed bit stream of the ARBITRATION FIELD or during the ACK SLOT. Then no BIT ERROR occurs when a “dominant” bit is monitored. A TRANSMITTER send

4、ing a PASSIVE ERROR FLAG and detecting a “dominant” bit does not interpret this as a BIT ERROR.</p><p>　　STUFF ERROR：</p><p>　　A STUFF ERROR has to be detected at the bit time of the 6th consecu

5、tive equal bit level in a message field that should be coded by the method of bit stuffing.</p><p>　　CRC ERROR：</p><p>　　The CRC sequence consists of the result of the CRC calculation by the tra

6、nsmitter. The receivers calculate the CRC in the same way as the transmitter. A CRC ERROR has to be detected， if the calculated result is not the same as that received in the CRC sequence.</p><p>　　FORM ERRO

7、R：</p><p>　　A FORM ERROR has to be detected when a fixed-form bit field contains one or more illegal bits. (Note， that for a Receiver a dominant bit during the last bit of END OR FRAME is not treated as FORM

8、 ERROR).</p><p>　　ACKNOWLEDGMENT ERROR</p><p>　　An ACKNOWLEDGMENT ERROR has to be detected by a transmitter whenever it</p><p>　　does not monitor a “dominant” bit during the ACK SLO

9、T.</p><p>　　Error Signaling：</p><p>　　A station detecting an error condition signals this by transmitting an ERROR FLAG. For an “error active” node it is an ACTIVE ERROR FLAG， for an “error pass

10、ive” node it is a PASSIVE ERROR FLAG. Whenever a BIT ERROR， a STUFF ERROR， a FORM ERROR or an ACKNOWLEDGMENT ERROR is detected by any station， transmission of an ERROR FLAG is started at the respective station at the nex

11、t bit. Whenever a CRC ERROR is detected， transmission of an ERROR FLAG starts at the bit following the ACK DELIMITER， unless</p><p>　　FAULT CONFINEMENT OF CAN：</p><p>　　With respect to fault con

12、finement a unit may be in one of three states：</p><p>　　“error active” </p><p>　　“error passive”</p><p>　　“bus off” </p><p>　　An “error active” unit can normally take p

13、art in bus communication and sends an ACTIVE ERROR FLAG when an error has been detected.</p><p>　　An “error passive” unit must not send an ACTIVE ERROR FLAG. It takes part in bus communication， but when an e

14、rror has been detected only a PASSIVE ERROR FLAG is sent. Also after a transmission， an “error passive” unit will wait before initiating a further transmission. </p><p>　　A “bus off” unit is not allowed to h

15、ave any influence on the bus. (E.g. output drivers switched off). </p><p>　　For fault confinement two counts are implemented in every bus unit：</p><p>　　TRANSMIT ERROR COUNT：</p><p>

16、;　　RECEIVE ERROR COUNT：</p><p>　　These counts are modified according to the following rules (note that more than one rule may apply during a given message transfer)：</p><p>　　When a RECEIVER det

17、ects an error， the RECEIVE ERROR COUNTwill be increased by 1， except when the detected error was a BIT ERROR during the sending of an ACTIVE ERROR FLAG or an OVERLOAD FLAG.</p><p>　　When a RECEIVER detects a

18、 “dominant” bit as the first bit after sending an ERROR FLAG the RECEIVE ERROR COUNT will be increased by 8.</p><p>　　When a TRANSMITTER sends an ERROR FLAG the TRANSMIT ERROR COUNT is increased by 8.</p&

19、gt;<p>　　Exception 1：</p><p>　　If the TRANSMITTER is “error active” and detects an ACKNOWLEDG- MENT ERROR because of not detecting a “dominant” ACK and does not detect a “dominant” bit while sending i

20、ts PASSIVE ERROR FLAG.</p><p>　　Exception 2： </p><p>　　If the TRANSMITTER sends an ERROR FLAG because STUFF ERROR occurred during ARBITRATION， and should have been “recessive”， and has been sent

21、 as “recessive” but monitored as “dominant”.</p><p>　　In exceptions 1 and 2 the TRANSMIT ERROR COUNT is not changed.</p><p>　　If a TRANSMITTER detects a BIT ERROR while sending an ACTIVE ERROR F

22、LAG or an OVERLOAD FLAG the TRANSMIT ERROR COUNT is increased by 8.</p><p>　　If a RECEIVER detects a BIT ERROR while sending an ACTIVE ERROR FLAG or an OVERLOAD FLAG the RECEIVE ERROR COUNT is increased by 8

23、.</p><p>　　Any node tolerates up to 7 consecutive “dominant” bits after sending an ACTIVE ERROR FLAG， PASSIVE ERROR FLAG or OVERLOAD FLAG. After detecting the 14th consecutive “dominant” bit (in case of an A

24、CTIVE ERROR FLAG or an OVERLOAD FLAG) or after detecting the 8th consecutive “dominant” bit following a PASSIVE ERROR FLAG， and after each sequence of additional eight consecutive “dominant” bits every TRANSMITTER increa

25、ses its TRANSMIT ERROR COUNT by 8 and every RECEIVER increases its RECEIVE ERROR COU</p><p>　　After the successful transmission of a message (getting ACK and no error until END OF FRAME is finished) the TRAN

26、SMIT ERROR COUNT is decreased by 1 unless it was already 0.</p><p>　　After the successful reception of a message (reception without error up to the ACK SLOT and the successful sending of the ACK bit)， the RE

27、CEIVE ERROR COUNT is decreased by 1， if it was between 1 and 127. If the RECEIVE ERROR COUNT was 0， it stays 0， and if it was greater than 127， then it will be set to a value between 119 and 127.</p><p>　　A

28、node is “error passive” when the TRANSMIT ERROR COUNT equals or exceeds 128， or when the RECEIVE ERROR COUNT equals or exceeds 128. An error condition letting a node become “error passive” causes the node to send an ACTI

29、VE ERROR FLAG.</p><p>　　A node is “bus off” when the TRANSMIT ERROR COUNT is greater than or equal to 256.</p><p>　　An “error passive” node becomes “error active” again when both the TRANSMIT ER

30、ROR COUNT and the RECEIVE ERROR COUNT are less than or equal to 127.</p><p>　　An node which is “bus off” is permitted to become “error active” (no longer “bus off”) with its error counters both set to 0 afte

31、r 128 occurrence of 11 consecutive “recessive” bits have been monitored on the bus.</p><p><b>　　Note：</b></p><p>　　An error count value greater than about 96 indicates a heavily dist

32、urbed bus. It may be of advantage to provide means to test for this condition.</p><p><b>　　Note：</b></p><p>　　Start-up / Wake-up：</p><p>　　If during start-up only 1 node

33、 is online， and if this node transmits some message， it will get no acknowledgment， detect an error and repeat the message. It can become “error passive” but not “bus off” due to this reason.</p><p><b>

34、;　　錯誤處理</b></p><p><b>　　錯誤檢測：</b></p><p>　　有以下5 種不同的錯誤類型（這5 種錯誤不會相互排斥）</p><p>　　位錯誤（Bit Error）</p><p>　　單元在發(fā)送位的同時也對總線進(jìn)行監(jiān)視。如果所發(fā)送的位值與所監(jiān)視的位值不相符合，則在此位時間里檢

35、測到一個位錯誤。但是在仲裁場（ARBITRATION FIELD）的填充位流期間或應(yīng)答間隙（ACK SLOT）發(fā)送一“隱性”位的情況是例外的。此時，當(dāng)監(jiān)視到一“顯性”位時，不會發(fā)出位錯誤。當(dāng)發(fā)送器發(fā)送一個被動錯誤標(biāo)志但檢測到</p><p>　　“顯性”位時，也不視為位錯誤。</p><p>　　填充錯誤（Stuff Error）：</p><p>　　如果在使用位

36、填充法進(jìn)行編碼的信息中，出現(xiàn)了第6 個連續(xù)相同的位電平時，檢測到一個填充錯誤。</p><p>　　CRC 錯誤（CRC Error）：</p><p>　　CRC 序列包括發(fā)送器的CRC 計算結(jié)果。接收器計算CRC 的方法與發(fā)送器相同。如果計算結(jié)果與接收到CRC 序列的結(jié)果不相符，則檢測到一個CRC 錯誤。 形式錯誤（Form Error）：</p>&l

37、t;p>　　當(dāng)一個固定形式的位場含有1 個或多個非法位，則檢測到一個形式錯誤。(備注：接收器的幀末尾最后一位期間的顯性位不被當(dāng)作幀錯誤)</p><p>　　應(yīng)答錯誤（Acknowledgment Error）：</p><p>　　只要在應(yīng)答間隙（ACK SLOT）期間所監(jiān)視的位不為“顯性”，則發(fā)送器會檢測到一個應(yīng)答錯誤。</p><p><b>

38、　　錯誤標(biāo)定：</b></p><p>　　檢測到錯誤條件的站通過發(fā)送錯誤標(biāo)志指示錯誤。對于“錯誤主動”的節(jié)點，錯誤信息為“主動錯誤標(biāo)志”，對于“錯誤被動”的節(jié)點，錯誤信息為“被動錯誤標(biāo)志”。站檢測到無論是位錯誤、填充錯誤、形式錯誤，還是應(yīng)答錯誤，這個站會在下一位時發(fā)出錯誤標(biāo)志信息。只要檢測到的錯誤的條件是CRC 錯誤，錯誤標(biāo)志的發(fā)送開始于ACK 界定符之后的位（其他的錯誤條件除外）。</p&g

39、t;<p>　　CAN的故障界定：</p><p>　　至于故障界定，單元的狀態(tài)可能為以下三種之一：</p><p><b>　　“錯誤主動”</b></p><p><b>　　“錯誤被動”</b></p><p><b>　　“總線關(guān)閉”</b></p

40、><p>　　“錯誤主動”的單元可以正常地參與總線通訊并在錯誤被檢測到時發(fā)出主動錯誤標(biāo)志。</p><p>　　“錯誤被動”的單元不允許發(fā)送主動錯誤標(biāo)志?！板e誤被動”的單元參與總線通訊，在錯誤被檢測到時只發(fā)出被動錯誤標(biāo)志。而且，發(fā)送以后，“錯誤被動”單元將在初始化下一個發(fā)送之前處于等待狀態(tài)。</p><p>　　“總線關(guān)閉”的單元不允許在總線上有任何的影響（比如，關(guān)閉輸

41、出驅(qū)動器）。</p><p>　　在每一總線單元里使用兩種計數(shù)以便故障界定：</p><p><b>　　發(fā)送錯誤計數(shù)</b></p><p><b>　　接收錯誤計數(shù)</b></p><p>　　這些計數(shù)按以下規(guī)則改變（注意，在給定的報文發(fā)送期間，可能要用到的規(guī)則不只一個）：</p>

42、<p>　　當(dāng)接收器檢測到一個錯誤，接收錯誤計數(shù)就加1。在發(fā)送主動錯誤標(biāo)志或過載標(biāo)志期間所檢測到的錯誤為位錯誤時，接收錯誤計數(shù)器值不加1。</p><p>　　當(dāng)錯誤標(biāo)志發(fā)送以后，接收器檢測到的第一個位為“顯性”時，接收錯誤計數(shù)值加8。</p><p>　　當(dāng)發(fā)送器發(fā)送一錯誤標(biāo)志時，發(fā)送錯誤計數(shù)器值加8</p><p><b>　　例外情況1：

43、</b></p><p>　　發(fā)送器為“錯誤被動”，并檢測到一應(yīng)答錯誤，此應(yīng)答錯誤由檢測不到一“顯性”ACK以及當(dāng)發(fā)送被動錯誤標(biāo)志時檢測不到一“顯性”位而引起。</p><p><b>　　例外情況2：</b></p><p>　　發(fā)送器因為填充錯誤而發(fā)送錯誤標(biāo)志。此填充錯誤發(fā)生于仲裁期間，引起填充錯誤是由于：填充位位于RTR 位之

44、前，并已作為“隱性”發(fā)送，但是卻被監(jiān)視為“顯性”。</p><p>　　例外情況1和例外情況2時，發(fā)送錯誤計數(shù)器值不改變。</p><p>　　發(fā)送主動錯誤標(biāo)志或過載標(biāo)志時，如果發(fā)送器檢測到位錯誤，則發(fā)送錯誤計數(shù)器值加8。</p><p>　　當(dāng)發(fā)送主動錯誤標(biāo)志或過載標(biāo)志時，如果接受器檢測到位錯誤（位錯誤），則接收錯誤計數(shù)器值加8。</p><p

45、>　　在發(fā)送主動錯誤標(biāo)志、被動錯誤標(biāo)志或過載標(biāo)志以后，任何節(jié)點最多容許7個連續(xù)的 “顯性”位。</p><p>　　以下的情況，每一發(fā)送器將它們的發(fā)送錯誤計數(shù)值加8，及每一接收器的接收錯誤計數(shù)值加8：</p><p>　　當(dāng)檢測到第14個連續(xù)的“顯性”位后；</p><p>　　在檢測到第8個跟隨著被動錯誤標(biāo)志的連續(xù)的“顯性”位以后；</p>&

46、lt;p>　　在每一附加的8個連續(xù)“顯性”位順序之后。</p><p>　　報文成功傳送后（得到ACK 及直到幀末尾結(jié)束沒有錯誤），發(fā)送錯誤計數(shù)器值減1，除非已經(jīng)是0。</p><p>　　如果接收錯誤計數(shù)值介于1和127之間，在成功地接收到報文后（直到應(yīng)答間隙接收沒有錯誤，及成功地發(fā)送了ACK 位），接收錯誤計數(shù)器值減1。如果接收錯誤計數(shù)器值是0，則它保持0，如果大于127，則它會

47、設(shè)置一個介于119 到127 之間值。</p><p>　　當(dāng)發(fā)送錯誤計數(shù)器值等于或超過128 時，或當(dāng)接收錯誤計數(shù)器值等于或超過128 時，節(jié)點為“錯誤被動”。讓節(jié)點成為“錯誤被動”的錯誤條件致使節(jié)點發(fā)出主動錯誤標(biāo)志。</p><p>　　當(dāng)發(fā)送錯誤計數(shù)器值大于或等于256 時，節(jié)點為“總線關(guān)閉”。</p><p>　　當(dāng)發(fā)送錯誤計數(shù)器值和接收錯誤計數(shù)器值都小于或

48、等于127 時，“錯誤被動”的節(jié)點重新變?yōu)椤板e誤主動”。</p><p>　　在總線監(jiān)視到128 次出現(xiàn)11 個連續(xù)“隱性”位之后，“總線關(guān)閉”的節(jié)點可以變成“錯誤主動”（不再是“總線關(guān)閉”），它的錯誤計數(shù)值也被設(shè)置為0。</p><p><b>　　備注：</b></p><p>　　一個大約大于96 的錯誤計數(shù)值顯示總線被嚴(yán)重干擾。最好能夠