Subject:
Re: [gnupic] Potential PIC project ?
From:
Rick Altherr ####@####.####
Date:
31 Dec 2005 18:40:15 +0000
Message-Id: <72D6C47D-BFA1-4726-A59A-F2A6EA2191C2@kc8apf.net>
See below
--
Rick Altherr
####@####.####
"He said he hadn't had a byte in three days. I had a short, so I
split it with him."
-- Slashdot signature
On Dec 31, 2005, at 6:57 AM, ####@####.#### wrote:
> Ser/Par-port to USB-based flash-mem-sticks ?
>
> I still maintain that PIC users have been misled.
> The basic PIC architecture [small memory space], only made
> sense and was justified for SSI [was it 8, 12, 18 pin DIL - I've
> forgotten].
>
> For the types of projects now handled by PIC, a 'proper' uProc, with
> [not a Harvard architecture] a 16bit adr-space is cheaper.
That all depends on the project. I have a lot of Atmel ATmega8s and
they do
have some nice advantages (GCC support, libc, etc), but the number of
peripheral interfaces available on the same class of device is limited
(ATmega8s have plenty of ADC channels, but no interrupt on change, or
other similar features unless you move up to a much larger part).
The PICs do have many
quirks and can be a pain to program, but they do serve a low price
point with
the necessary functionality. For most cases, a PIC is superior to
the Atmels
simply for the additional features offered at the price point. For
some cases,
however, the additional ease of the Atmels is better. But, in either
case,
the Havard architecture has little to do with which uC is
appropriate. The
instructions available, the peripherals, and the supporting tools are
more
important.
> ------------
> USB-based flash-mems have flooded the market, and are very
> cost effective. Yet still many machines in use don't have USB ports.
>
> Apparently the USB-based flash-mem-sticks are SCSI based.
> Which will be replaced first [by USB]: ser [RS232] or par-port ?
>
USB-based flash devices are actually really USB. The OS chooses to
view them
as a SCSI device, but there is actually no reason that they cannot be
viewed
any other way.
> I always thought of the par-port [centronics] as being the most
> 'universal', and that's why Iomega chose the make a par-port
> external Zip-drive. Probably the par-port, even with minimum
> input lines - 3 I think - is faster than RS232 ?
>
The parallel port pushes data in parallel (hence the name), and requires
at least 1 pin per bit of data you wish to send in parallel. Since the
overall speed of a parallel port is slower than RS-232, the number of
bits
sent in parallel is high to achieve an overall high thru-put.
> There could be a lot of users for [PIC based] adaptors for USB-flash.
>
> Including a notebook, of my 4 machines only one has USB-ports.
> So a main advantage of USB-flash tranporting data between
> machines is not available. Diskette is becoming increasingly
> unreliable and annoying ?
>
I agree that an adapter could be useful, but what you are actually
planning
to make is a serial or parallel port USB adapter. That is a fairly
complex
beast, but could possibly be done. Overall it would probably be
easier to
build a serial port device than a parallel port device, but either way
will involve an large amount of code to simulate a USB root, not to
mention
the necessary drivers for the OS you wish to use it under.
> == Chris Glur.
>
>
>
>
>
>
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