Thanks for the link Mark. Lots of information in there.
Kurt
On Friday, June 19, 2015 1:09 AM, Mark Wickens <[email protected]>
wrote:
Chapter 14 of the Oppendahl book
http://www.club100.org/ftp/m100-oppedahl-2.pdf has a good summary of the
hardware.
Basically the port provides a 1 or 0. With a barcode you'd time the
transitions to form the number. Clearly the hardware is fairly primitive and a
lot needs to be dealt with in the software. Voltage to frequency converters
work well in this situation if you want analogue to digital conversion.
Regards, Mark.
On 18/06/15 23:34, Kurt McCullum wrote:
It's curious that it can be passively checked or tied to an interrupt.I read
one of the Portable 100 articles about attaching a photo transistor to it which
got me thinking about a few projects. I think it was being used as a stopwatch
for that application. But it's definitely a port with possibilities.
Kurt
On Thursday, June 18, 2015 3:22 PM, MikeS <[email protected]> wrote:
It's actually a pretty useful port and the +5V availability is a real
plus. There's a Portable100 article about using it as a tachometer (although
ISTR that the software left something to be desired) and although I haven't
tried it it should be a straightforward interface for a temperature- or
voltage-to-frequency converter (e.g. Maxim 6576 & 6577, Analog AD7740 etc.,
even just a 555). If memory serves, I think Steve did something like that for
his aquarium heater or something similar. And you can even use it to read bar
codes! m
----- Original Message ----- From: Kurt McCullum To: Model 100 Discussion
Sent: Thursday, June 18, 2015 5:39 PM Subject: Re: [M100] Barcode Wand
Thanks for the info!
On Thursday, June 18, 2015 2:14 PM, Doug Jackson <[email protected]> wrote:
Yes,
From memory, the wand has *no* smarts - the phototransistor is basically
converted to TTL and provided to the interface pin.
It was very similar to the HEDS3000 series wands that HP used on the HP41
(http://www.ecse.rpi.edu/Courses/CStudio/data%20sheets/HEDS3050.PDF) I have
both the TRS80 wand and the HP in storage here if anybody wants information.
Doug
On 19/06/2015 6:56 AM, Kurt McCullum wrote:
Does the barcode interface use a TTL level signal? Meaning any TTL barcode
scanner that is wired properly could be used?
Kurt
--
Kindest Regards,
Doug Jackson
<b>Dougs Word Clocks.com Pty Ltd</b>
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