NNTP-Posting-Date: Fri, 17 Jan 2003 14:47:23 -0600
From: firstname.lastname@example.org (John Fields)
Subject: Re: serial lcd tester using discretes only ? is it possible
Date: Fri, 17 Jan 2003 20:51:35 GMT
Organization: Austin Instruments, Inc.
References: <3E2710E5.email@example.com> <3E28644A.firstname.lastname@example.org>
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On Fri, 17 Jan 2003 20:15:06 +0000, Andy
>Gary Tait wrote:
>>On Thu, 16 Jan 2003 20:07:01 +0000, Andy
>>>I have been given a couple of serial Lcd displays , is there anyway I
>>>can test these without having to link them to a PC or pic chip , I have
>>>built one for checking parrallel Lcds that just uses dip switches and
>>>that one works fine .. ... thanks in advance andy
>>Wy not a micro? You can get them relativel cheap, build a rather
>>simple programmer, and program them with a free compiler.
>>I have done an AVR AT902313 for next to nothing, probably<$20.
>don't really want to mess around with micro controllers - my
>programming etc isnt too hot on machine code , just thought a nice
>simple interface would allow me to play around with the displays, but
>then again the parrallel lcd seem to be much easier to control via
>discretes . ..pity about the prices though , the serial displays are
>only £2 a piece parrallels are from about £10+
Since the parallel input displays only reguire you to set up control
and display data using the dip switches and then clock the data into
the display with an edge which can be generated using anpther dip
switch, there are really no critical timing requirements as long as
the power supply risetime is short enough to preclude the necessity
of initializing the display via software.
Such is _not_ the case with a serial input display, which requires
the control and display data to be contained within a much more
tightly controlled time frame. It's conceivable, as Spehro noted,
that you could build yourself an interface using a couple of
parallel-in serial-out shift registers, but trying to do it with
discretes, it seems to me, would be an exercise in futility...
I'd be interested in knowing where you're getting your displays.
Because of IO limitations I'm currently using three µP IO lines to
drive an 8 bit parallel display from a serial-in parallel-out shift
register and I'm paying about $8 for the displays. If you're paying
about $3 (I don't know what the exchange rate is) for serial units
and I can get them for the same price you do I could get rid of the
SR and save a bunch of money just on the price of the displays.