【正文】 coding Example: ? Transmitter keeps running track of current disparity (it is either RD, RD+ or neutral) Neutral means the disparity tracker keeps the previous RD or RD+ value ? A Running Disparity of RD+ is always followed by an RD encoding and vice versa If Running Disparity is RD+, the following is encoded for the data byte F1: HGF EDCBA ? abcdei fghj 111 10001 ? 100011 0111 (RD encoding) If Running Disparity is RD, the following is encoded for the data byte F1: HGF EDCBA ? abcdei fghj 111 10001 ? 100011 0001 (RD+ encoding) 12/4/2023 63 8b/10b Disparity Encoding Example: ? Note that the number of ones and zeros in the currently chosen encoding works to balance out the offset in the number of ones and zeroes (tracked by the Running Disparity value) from the previous encoding . : Don’t confuse the definition of Positive Disparity with the RD+ encoding choice! Positive Disparity means there is a current running total of more ones than zeros! Thus, an RD+ encoding generally has more zeros than ones! ? Also note that it is possible that the 4bit subblock of a RD or RD+ symbol encoding can yield a negative or positive disparity, respectively thus forcing more than one RD encoding to be used consecutively… 12/4/2023 64 Summary: Example conversion HEX Data Byte (8b) to be Encoded OR Binary Data Byte (8b) to be Encoded 10b Encoded symbol (RD) 10b Encoded symbol (RD+) F1 100011 0111 100011 0001 1111 0001 12/4/2023 65 Possible Patterns… ? Repeating Comma [] Pattern (RD followed by RD+): 001111 1010 110000 0101 001111 1010 110000 0101 (RD) (RD+) (RD) (RD+) 6 bit encoding starts with an RD and uses an positive disparity encoding….6 bits encoding yields an RD+…..4bit encoding starts with a RD +…4bit encoding picks a negative (or neutral encoding) and thus yields a neutral and thus keeps the RD+. Checks out…. ? Low Frequency Pattern?? ( (RD followed by RD) 011110 0100 011110 0100 011110 0100 011110 0100 (RD) (RD) (RD) (RD) 100001 1011 100001 1011 100001 1011 100001 1011 (RD+) (RD+) (RD+) (RD+) 12/4/2023 66 Possible Patterns… ? High transition density/frequency pattern: (RD followed by RD+) 101010 1010 101010 1010 101010 1010 101010 1010 (RD) (RD+) (RD) (RD+) ? Low transition density pattern: (RD) (RD+) (although is reserved....) 001111 1000 001111 1000 001100 1100 001111 1000 001100 1100 (RD) (RD+) (RD) (RD+) (RD) (RD+) 1100110110 0011000110 1100110110 0011000110 (RD) (RD+) (RD) (RD+) ? Composite pattern: (RD) (RD) 011110 0001 101100 1000 011110 0001 101100 1000 (RD) (RD) (RD) (RD) 12/4/2023 67 References ? Infiniband Architecture Release Specification October 24, 2023, Volume 2, Section (beginning with page 66) ? Franaszek Widmer (IBM) Patent 4,486,739 December 4, 1984, Byte Oriented DC Balanced 8B/10B Partitioned Block Transmission Code ? 3GIO Architecture Specification Key Developer Draft August 21, 2023, Appendix C, pg148154 ? ANSI , clause 11 (and also IEEE , ). 12/4/2023 68 Other sources of mon mode ? A DC voltage will build up across the blocking capacitor if the charge and discharge is not equal. ? We have see this can happen if the number of bits is unbalance. ? Another source of imbalance is possible if the duty cycle of the one and zeros is not 50%. ? This can happen in two ways The time for a one differs from that of a zero. This can be caused by edge jitter. The rising time and falling time are miss matched On the next slide we will take our example with 101010101010 pattern and change the rise time to 50 ps and fall time to 150 ps for the single ended signals 12/4/2023 69 CM offset from tr/tf mismatch Reproduce this at package 2 (receiver) 12/4/2023 70 靜夜四無(wú)鄰，荒居舊業(yè)貧。 , February 2, 2023 雨中黃葉樹(shù)，燈下白頭人。 21:33:0121:33:0121:332/2/2023 9:33:01 PM 1以我獨(dú)沈久，愧君相見(jiàn)頻。 :33:0121:33Feb232Feb23 1故人江海別，幾度隔山川。 21:33:0121:33:0121:33Thursday, February 2, 2023 1乍見(jiàn)翻疑夢(mèng)，相悲各問(wèn)年。 :33:0121:33:01February 2, 2023 1他鄉(xiāng)生白發(fā)，舊國(guó)見(jiàn)青山。 2023年 2月 2日星期四 下午 9時(shí) 33分 1秒 21:33: 1比不了得就不比，得不到的就不要。 。 2023年 2月 下午 9時(shí) 33分 :33February 2, 2023 1行動(dòng)出成果，工作出財(cái)富。 2023年 2月 2日星期四 9時(shí) 33分 1秒 21:33:012 February 2023 1做前，能夠環(huán)視四周；做時(shí)，你只能或者最好沿著以腳為起點(diǎn)的射線向前。 下午 9時(shí) 33分 1秒 下午 9時(shí) 33分 21:33: 沒(méi)有失敗，只有暫時(shí)停止成功！。 , February 2, 2023 很多事情努力了未必有結(jié)果，但是不努力卻什么改變也沒(méi)有。 21:33:0121:33:0121:332/2/2023 9:33:01 PM 1成功就是日復(fù)一日那一點(diǎn)點(diǎn)小小努力的積累。 :33:0121:33Feb232Feb23 1世間成事，不求其絕對(duì)圓滿，留一份不足，可得無(wú)限完美。 21:33:0121:33:0121:33Thursday, February 2, 2023 1不知香積寺，數(shù)里入云峰。 :33:0121:33:01February 2, 2023 1意志堅(jiān)強(qiáng)的人能把世界放在手中像泥塊一樣任意揉捏。 2023年 2月 2日星期四 下午 9時(shí) 33分 1秒 21:33: 1楚塞三湘接，荊門(mén)九派通。 。 2023年 2月 下午 9時(shí) 33分 :33February 2, 2023 1少年十五二十時(shí)，步行奪得胡馬騎。 2023年 2月 2日星期四 9時(shí) 33分 1秒 21:33:012 February 2023 1空山新雨后，天氣晚來(lái)秋。 下午 9時(shí) 33分 1秒 下午 9時(shí) 33分 21:33: 楊柳散和風(fēng)，青山澹吾慮。 , February 2, 2023 閱讀一切好書(shū)如同和過(guò)去最杰出的人談話。 21:33:0121:33:0121:332/2/2023 9:33:01 PM 1越是沒(méi)有本領(lǐng)的就越加自命不凡。 :33:0121:33Feb232Feb23 1越是無(wú)能的人，越喜歡挑剔別人的錯(cuò)兒。 21:33:0121:33:0121:33Thursday, February 2, 2023 1知人者智，自知者明。勝人者有力，自勝者強(qiáng)。 :33:0121:33:01February 2, 2023 1意志堅(jiān)強(qiáng)的人能把世界放在手中像泥塊一樣任意揉捏。 2023年 2月 2日星期四 下午 9時(shí) 33分 1秒 21:33: 1最具挑戰(zhàn)性的挑戰(zhàn)莫過(guò)于提升自我。 2023年 2月 下午 9時(shí) 33分 :33February 2, 2023 1業(yè)余生活要有意義，不要越軌。 2023年 2月 2日星期四 9時(shí) 33分 1秒 21:33:012 February 2023 1一個(gè)人即使已登上頂峰，也仍要自強(qiáng)不息。 下午 9時(shí) 33分 1秒 下午 9時(shí) 33分 21:33: MOMODA POWERPOINT Lorem ipsum dolor sit amet, consectetur adipiscing elit. 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