Zorro 3 Bus Speed

[trekiej]

Wikipedia says it is 150 MB/sec, I assume theoretical.
What do you think?
Did any card ever use that close to that much bandwidth?

http://en.wikipedia.org/wiki/List_of_device_bandwidths

[trekiej]

cool

[trekiej]

One of the parts of the Asynchronous 68000 bust transfer is the wait states that are added while waiting for /DTACK. /DTACK can be created by a counter that is activated by /AS which is active low Address Strobe. The clock counts for a number of cycles then applies /DTACK.
What is also interesting is the circuits used to interface SDRAM. The address gets multiplexed by a counter to do the two sets of address reads, that is from the cpu to sdram. This is done after /AS and before /DTACK.

[trekiej]

What is nice about Asynchronous timing is that the cards can work at different speeds.
*
DMA, and then CPU accessing the the PIC's memory maybe where the clock comes in to play, to speculate.

[trekiej]

@ tnt23
What I am refering to is that a memory chip does not or appear to not have that ability but a PIC ( add-on card )does/could. I do not know of any SDRAM chips that have ability, the author did not specify that.

The author shows a counter that counts to a specified amount of time and aserts a /DTACK. The counter is started by /AS. It appears that it does not guarantee that data has made it safely.

I believe that there is a situation after so many wait-states that under the right circumstances the read/write can be repeated. That is something I have to look up.

I am not trying to say that the wait is arbitrary. Looking at the timing diagram, I believe 3 things can happen, success, bus error, or repeat.
Sure, from /AS to /DTACK is X number of cycles for which this would all happpen.

I hope this clears up what I mean.

[trekiej]

No problem, I need to further investigate where the clock comes in to play.
Before studying the 68000 the clock is/was used to time everthing, it seems, at least in appearance, that one could get away with using R/W and ENable lines for timing.
That is me speculating.

[trekiej]

@Zac67
You know more about that than I do, humble grin.
As far as I can tell, and to speculate, to slow the system down to get more performance reminds me of an accordion effect.
The accordion effect is like a string of cars going over a speed bump. They get bunched up at the speed bump. Then they pick after the speed bump. It is as fast as the slowest chip or function.
IMHO, lol

[trekiej]

I was wandering if I should answer the above post.
Here goes, I do not buy PC hardware except for those rare times I buy PC hardware.
That is how it sounds.