4 ms·
He said "synchronous" (synchronized by a clock), not "sequential."
by gmfawcett 8y ago
He said "synchronous" (synchronized by a clock), not "sequential."
- bogomipz 8y ago"Synchronous" is a type of sequential circuit. The "synchrony" or sequencing is derived from the clock signal. https://en.wikipedia.org/wiki/Sequential_logic https://en.wikipedia.org/wiki/Sequential_logic
- gmfawcett 8y agoYes, you're right of course. Looking at it again, I'm reading Wirth's statement as pretty much a bog-standard endorsement of synchronous circuit design.
- bogomipz 8y agoYeah it's the "Every variable and register is defined by one and only one expression combinational circuit)" part that confuses me, since he seems to use that to support the endorsement of synchronous design. But maybe I'm just reading it wrong though.
- gmfawcett 8y agoChanneling my inner Wirth, I think he's just saying that, for the duration of any given clock cycle, synchronization ensures that every combinational building-block within the sequential circuit will have a consistent state.
- analognoise 8y agoThere are two parts to a synchronous design - the combinatorial bits, and the flip-flops. /----\ |-----| / \ | Q| | COMB |---|D | \ / |>CLK | \----/ |-----| I think what he's getting at is that any combinational logic that goes in a register is defined in one place - he's not doing complex statements. It sounds like he's doing a very (terse) RTL style. This makes it very clear what your synthesizer will do with it - he isn't trying to be clever on the RTL front. We should email him and ask!
- bogomipz 8y agoThanks for channeling your "inner Wirth" :) Also thanks for the ascii diagram. In re-reading that passage this all makes good sense now. Cheers.