Date: Fri, 19 Feb 2010 17:27:33 +0000 From: spellberg_robert <emailrob@emailrob.com> To: fbsd_chat <freebsd-chat@freebsd.org> Subject: Re: LinuxBSDos.com article Message-ID: <4B7ECA05.8070502@emailrob.com> References: <41051be3118c6.4b7d2ce2@sasktel.net> <86ocjlzi64.fsf@ds4.des.no> <4B7E5BFA.6020505@infracaninophile.co.uk> <86bpflzelp.fsf@ds4.des.no>
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i completely sympathize with all of those who mourn the loss of a favored, albeit esoteric, thingy.
it is particularly sad when that thingy was wildly popular, back in the before_time.
while not directly related to freebsd, at --this-- time,
i observe that the, formerly universal, rs_232 serial_port is no_longer always included on motherboards.
i am fond of the 908_series of embedded_controllers from freescale [ nee motorola ].
to program the flash_rom,
i could spend several_hundred dollars on a dedicated appliance,
which may_or_may_not program all of the devices which interest me.
it may not support future devices; if it breaks, i can't fix it.
on the other_hand, i can roll_my_own.
this costs a_few_tens of dollars, applies to any device using this interface and i can fix it
[ it should be noted that the things that i build tend to not_break, because i am the repair_man ].
the simplest approach requires an easily_programmed computer with a rs_232 port.
the interface is a single pin.
the pin used varies from part to part, which is why the appliance may not support all devices.
i need half_duplex, 9600 bps, 8 bits, no parity, 1 stop_bit.
converting half_duplex to full_duplex is easy.
i need complementary 12_ to 15_volt supplies, which are downright cheap.
this is child's_play.
[ for those who find an 8_bit cpu to be interesting,
a web_site page with a link to a pdf [ 2.6 mb ] of the data_sheet for
a representative and particularly_popular member of the series, the 908qy4,
may be found here:
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=HC08Q&tab=Documentation_Tab&pspll=1&nodeId=01624684497663&SelectedAsset=Documentation&ProdMetaId=PID/DC/HC08Q&fromPSP=true&assetLockedForNavigation=true&componentId=2&leftNavCode=1&pageSize=25&Documentation=Documentation/00610Ksd1nd%60%60Data%20Sheets
]
on the freebsd side, i need to dissect the man_pages so that i can control the 16550.
the authors of these pages, while well_meaning, considered rs_232 as a means of
talking to a modem [ a full_featured appliance ] or
talking to a terminal [ also, a full_featured appliance ].
i found myself reading between the lines, frequently.
rs_232 works very well
for short messages,
over short distances,
in environments of up_to_moderate noise,
using inexpensive components.
for these reasons, it --will-- be made illegal; de_facto, if not de_jure.
it may be several years [ ten ? ], but, sooner_or_later,
freebsd will drop support for and/or remove the capability of implementing,
what are coming to be called, the "legacy" serial and parallel ports,
because the general_public will not be using them.
i will mourn this, but, i will understand, because
freebsd_people are, statistically, software_people, not hardware_people.
i will find a work_around,
either by implementing the new interface or by converting between new and old.
as long as i have six addressable bits whose level i can flip individually [ 3 out and 3 in ],
i can rig a full_duplex link that runs as fast as the slower end_point hardware.
apparently [ from what i read ], statistically, freebsd_people are not musicians, either.
neither am i; although i --did-- take violin lessons as a youngster.
so, make mine bob wills or jascha heifetx, please.
rob
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