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Politics : Formerly About Advanced Micro Devices -- Ignore unavailable to you. Want to Upgrade?

To: Elmer who wrote (51759)	3/6/1999 1:52:00 PM
From: Ali Chen	Read Replies (3) \| Respond to of 1572707

<Sorry Ali but you got things backwards. 'Sequential gates'? You mean combinational gates between sequential elements.> If you do not understand what people mean when they talk about digital logic, go learn something first before barking, student. The "number of sequential gates" means the number of base logical elements (NORs, NANDs, XORs, or whatever the basic library element is) across whom a worst-case signal has to propagate before the final logical state of the particular logical function is achieved. For an example that is comprehendable for you, a simplest R-S-flip-flop may be built using two 2-NAND gates. If it has a 1T delay when flipping from 0 to 1 on direct output, the inverted output will have 2T delay because the signal has to propagate across TWO gates to get through. There could be thousands of these flip-flops in parallel, but the "gate depth" is 2 in this case. More complex circuits like decoders, comparators, shifters, multipliers have apparently much more logic inside, so some conditional or preset signals have to propagate across several gates sequentionally. There is a whole art of cuircuit synthesis that is aimed to minimize this "sequentionality". To understand the above topic up to the rights to judge what is backward and what is straightforward, your background should include at least the course like this: ece.wpi.edu see Chapter 8. Have a nice education, Elmer... <end of the lecture>