Odd/Even bus invert with two-phase transfer for buses with coupling
Odd/Even bus invert with two-phase transfer for buses with coupling
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DOI：
10.1109/lpe.2002.146715
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发表时间：
2002-08
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通讯作者：
Yan Zhang;J. Lach;K. Skadron;Mircea R. Stan
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文献类型：
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作者：
Yan Zhang;J. Lach;K. Skadron;Mircea R. Stan
在深亚微米工艺中，片上总线之间的耦合电容成为主要因素。在旧技术中，编码以减少各条线的开关活动足以减少总线上的功率，但深亚微米总线需要减少线之间耦合活动的新编码技术。一种这样的编码技术使用简单的观察，即耦合电容总是通过相邻总线线路上的活动来充电和放电，其中一条线路具有奇数，另一条线路具有偶数（如果总线线路被“按顺序”编号）。因此，我们建议通过独立地控制奇数和偶数总线与两个单独的线，奇数反转，偶数反转线，分别减少耦合活动。我们通过比较奇数和偶数反转线（00，01，10，11）的四种可能情况下的耦合活动，然后选择具有最小耦合活动的值在总线上传输，从而获得显著的功耗降低。即使在编码之后，一对总线线路的耦合活动仍然强烈地依赖于数据。特别地，切换序列01/spl random/10和10/spl random/01导致比其他耦合事件多4倍的耦合能量耗散。因此，我们提出了一个有针对性的两相转移，以减少总功率只有对线进行这样的切换事件。
The coupling capacitances between on-chip bus lines become dominant in deep-submicron technologies. Coding to reduce the switching activity of the individual lines was enough to reduce power on buses in older technologies, but new coding techniques that reduce the coupling activity between lines are needed for deep-submicron buses. One such coding technique uses the simple observation that coupling capacitances are always charged and discharged by activity on neighboring bus lines, where one line has an odd number and the other has an even number (if bus lines are numbered "in-order"). We thus propose to reduce the coupling activity by independently controlling the odd and even bus lines with two separate lines, the Odd Invert, and Even Invert line, respectively. We obtain significant reductions in power simply by comparing the coupling activity for the four possible cases of the Odd and Even Invert lines (00, 01, 10, 11), and then choosing the value with the smallest coupling activity to transmit on the bus. Even after encoding, the coupling activity for a pair of bus lines is still strongly dependent on the data. In particular the toggling sequences 01/spl rarr/10 and 10/spl rarr/01 result in 4 times more coupling energy dissipation than other coupling events. We thus propose a targeted Two-Phase transfer in order to reduce total power only on the pairs of lines that carry such toggling events.