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Re: CPU's and boards for hobbyists?
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Ivan Shmakov
Nov 22, 2012, 11:59:22 AM11/22/12
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>>>>> Wilf <wilf...@live.com> writes:
[Cross-posting to news:comp.sys.misc, and dropping
news:comp.os.cpm (in favor of the former) from Followup-To:.]
> There is this one recently produced in Australia. The target market
> is I think people who had one in the 80's.
> http://www.microbeetechnology.com.au/
The point is that as a "remake", such a computer is not to be
expected to be cheap. And, indeed, it isn't.
For a "non-kit", one-board (cheap) computer, I'd probably check
Raspberry Pi or the Gooseberry board. Both are ought to be
rather fully-featured, with over than 29000 software packages
readily available [1].
[1] http://www.debian.org/
> The Maximite was another on based on a PIC device. Quite different
> but did have BASIC. http://geoffg.net/maximite.html
I've mentioned DuinoMite (a derivative system from a different
vendor) already in this thread.
Unfortunately, the designer behind Maximite, and also the author
of the MMBasic firmware bundled, has regretted his earlier
choice to release MMBasic as free software, as the design has
readily spawned a number of derivatives (including DuinoMite),
whose respective authors not necessarily credited him, or at
times provided inferior versions of the software, allegedly
harming his reputation.
... A feature of the design is the use of the SPI interface to
drive a VGA interface, which seems like a clever one (even if it
wasn't the first time SPI was used for such a trick.) However,
it made me wonder on what CPU frequency is used? (I see the
crystal, but I presume the chip has an internal frequency
multiplier.)
Also, I see that while the ATmega8-family MCU's are able to
drive SPI at half the core frequency, it's possible to get the
system's clock output at the CLKO pin. I wonder if it may make
sense to drive a parallel-to-serial chip (such as, e. g.,
74HC165) to achieve the 20 MHz pixel clock for such an
improvised VGA output? (I. e., instead of using the
SPI-internal shift register.)
--
FSF associate member #7257
[Cross-posting to news:comp.sys.misc, and dropping
news:comp.os.cpm (in favor of the former) from Followup-To:.]
> There is this one recently produced in Australia. The target market
> is I think people who had one in the 80's.
> http://www.microbeetechnology.com.au/
The point is that as a "remake", such a computer is not to be
expected to be cheap. And, indeed, it isn't.
For a "non-kit", one-board (cheap) computer, I'd probably check
Raspberry Pi or the Gooseberry board. Both are ought to be
rather fully-featured, with over than 29000 software packages
readily available [1].
[1] http://www.debian.org/
> The Maximite was another on based on a PIC device. Quite different
> but did have BASIC. http://geoffg.net/maximite.html
I've mentioned DuinoMite (a derivative system from a different
vendor) already in this thread.
Unfortunately, the designer behind Maximite, and also the author
of the MMBasic firmware bundled, has regretted his earlier
choice to release MMBasic as free software, as the design has
readily spawned a number of derivatives (including DuinoMite),
whose respective authors not necessarily credited him, or at
times provided inferior versions of the software, allegedly
harming his reputation.
... A feature of the design is the use of the SPI interface to
drive a VGA interface, which seems like a clever one (even if it
wasn't the first time SPI was used for such a trick.) However,
it made me wonder on what CPU frequency is used? (I see the
crystal, but I presume the chip has an internal frequency
multiplier.)
Also, I see that while the ATmega8-family MCU's are able to
drive SPI at half the core frequency, it's possible to get the
system's clock output at the CLKO pin. I wonder if it may make
sense to drive a parallel-to-serial chip (such as, e. g.,
74HC165) to achieve the 20 MHz pixel clock for such an
improvised VGA output? (I. e., instead of using the
SPI-internal shift register.)
--
FSF associate member #7257
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