[Oberon] [EXTERNAL] Re: List of boards in the Wikibook
skulski at pas.rochester.edu
Mon Jun 8 17:57:38 CEST 2020
> Your Web page doesn't have a list price. I think of putting something
> such as "300-500" in the table.
There is no set price because it strongly depends on the production volume. Please put a reference a reference to the web page. This is an open source, non-commercial project. I am trying to provide all the info for the informed decision making. Anyone, who has some sort of expectation, can confront these with numbers. ("Chinese computers retail for $5 apiece and they are so powerful. Can we have an Oberon board for about this much?") Make your own boards. I provided the files, go and get it. Find a cheaper assembly house, or do it yourself by hand. The board was intentionally designed to permit hand assembly for the day dreamers. A DIY version can be reasonably cheap!
> According to the Wikipedia article, the introductory price for the Mac
> Plus was 2599 US$; equivalent to over 6 k$ now. Really 500 dollars for
> a more powerful machine is a good bargain.
It was back then. Now we live in an era of cheap labor. Part of it is due to robotics. Nowadays robotics + high volume = $40 per Raspberry Pi. This set the expectations really low. And these are so powerful!
So the deal is: Go with the crowd, pay little, and do what everyone else is doing. Or go your own way and be prepared to pay a few hundred dollars. There is no third way. But people keep trying...
> USB power adapters are everywhere. Not required with the board?
Some sort of power is required. Either the usual 5 mm barrel or the mini USB, which can be one of these USB power adapters. Or it can be your laptop, while you are using JTAG/serial over USB to program the board.
> The front page of the book gets 500-1500 accesses/mo. Enthusiasts should notice available hardware.
Enthusiasts? Where are they?
> The description of ZBT mentions zero latency between read and write.
> The naive reader might expect ZBT would allow a faster machine
> compared to ASRAM.
ZBT can run about twice as fast as ASRAM, but there is more to it. ASRAM timing is specified in nanoseconds. ASRAM is not using any clock. ZBT is using the clock edges. Designing the ASRAM interface you have to count nanoseconds, while designing the ZBT interface you count clock cycles. FPGAs are good at clocking, and very poor at nanoseconds. Therefore ZBT better fits the FPGA methodology. We discussed it a little bit in the past.
My ideas about ZBT are summarized on the schematics. in general, I put a lot of reference information onto the schematic to have it handy. There is a timing diagram on that page and a few web pointers. This info is on the "ZBT decoupling page" where I had some extra space to fill. Look at the PDF version of the schematics if you do not have OrCAD.
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