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'Interfacing a PIC to HP infra-red serial port.'
1998\11\30@202647 by Don Holtz

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Does anyone have info on the serial protocol that HP uses to implement
their infra-red serial interface - for calculators and palmtops.

I have an HP-48S, and several HP palmtops that I would like to use to talk to
a PIC.

Any ideas?

Cheers,
Don


'Interfacing a PIC to HP infra-red serial port.'
1998\12\01@001039 by MattBeck
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Not sure of the other methods used, but I know the HP48 series is half duplex
serial com. It is software timed, the acutal IR led, and IR phototransistor
are memory mapped. There is no modulation or demodulation to worry about but
range is limited to about 12". Just use a phototransistor to read and a IR led
to write to the Hp48 using normal (8,N,1) serial com. (2400baud max). Matt

1998\12\01@011315 by Lynx {Glenn Jones}

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One problem here, the HP's receiver circuitry is limited to only a couple
of inches, i guess to keep people from cheeting on tests, The transmit
range, however, is much farther, In fact i can use my hp to turn on my tv
from accross the room (more than 10ft). Also, the signals are inverted,
that is, no IR light means 1 while IR light means 0. Hope this helps. (I
myself am planning on interfacing my HP to a MCU using its IR
capabilities, but i havent tried anything yet.)

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058209749445923078164062862089986280348253421170679

On Tue, 1 Dec 1998 spam_OUTMattBeckTakeThisOuTspamAOL.COM wrote:

> Not sure of the other methods used, but I know the HP48 series is half duplex
> serial com. It is software timed, the acutal IR led, and IR phototransistor
> are memory mapped. There is no modulation or demodulation to worry about but
> range is limited to about 12". Just use a phototransistor to read and a IR led
> to write to the Hp48 using normal (8,N,1) serial com. (2400baud max). Matt
>

1998\12\01@063231 by Russell McMahon

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I don't know if the latest HPs use the same protocol as the HP82240B
printer.
This is a 24 odd column standalone IR interfaced printer used with
the older IR capable calculators.

If they do, then the advice on this subject posted here seems to be
wrong. Perhaps the later units use a simpler protocol. If not, I can
help with the HP82240B protocol.HP can provide a very comprehensive
brochure on the protocol.

We connected to these directly for a vehicle based project but I also
tried using infra reed and it worked very successfully over  arrange
of 1 to 2 feet. More would have been easy. The serial protocol sends
bits which have a number of pulses of high or low depending on
whether a 1 or a 0. The pattern is not intuitive and is not straight
Manchester AFAIR. To convert to IR I simply gated the output of a 32
KHz oscillator using a 74C14 as the oscillator. HP say that the bits
must be synchronised with the 32 KHz signal but in my tests this did
not seem to be the case. In the limited tests that I did I got 100%
copy with asynchronous 32KHz oscillator. Also HPs specs for the
maximum and minimum number of 32 KHz pulses per bit suggest that I
was not violating this requirement.

I can probably turn up more details on the protocol if required -
this will not be the case if the other advice given is in fact
correct. Our system used an Atmel 2051 but I am (probably) not able
to release the code. PIC implementation should be easy. I looked at
an an IR version using a 6MHz ST6 but it was just too slow :-). PIC
should be easily fast enough to generate the 32KHz modulated pulses
directly.



regards




           Russell McMahon

From: Don Holtz <.....daholtzKILLspamspam@spam@AXIONET.COM>

>Does anyone have info on the serial protocol that HP uses to
implement
>their infra-red serial interface - for calculators and palmtops.
>
>I have an HP-48S, and several HP palmtops that I would like to use
to talk to
>a PIC.
>
>Any ideas?
>
>Cheers,
>Don
>

1998\12\01@103659 by Goovaerts

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This infrared that you use, does it implies the IrDA standard ?? Because I
have to implement IR following IrDA on a PIC16C63 !! If somebody sends you
some code, can you forward it to me ??
Thanks and greetings from Glenn Goovaerts !!!

{Original Message removed}

1998\12\01@112313 by Ricardo Seixas

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Hi Don,

       The doc you need is located on http://www.hpcalc.org/docs/misc/io2.txt
       There's also a lot of docs, including I2C, HP48 -> modem, digital
osciloscope,
etc,etc, check it out.
       http://www.hpcalc.org/

Hope this helps

Ricardo Seixas


{Quote hidden}

1998\12\01@142551 by gwaiche

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Hi!

Remember that HP48s (If it's about this HP IR port we are
talking about) only knows the Kermit protocol.

Cheers!

Gael


MattBeckspamKILLspamAOL.COM wrote:
>
> Not sure of the other methods used, but I know the HP48 series is half duplex
> serial com. It is software timed, the acutal IR led, and IR phototransistor
> are memory mapped. There is no modulation or demodulation to worry about but
> range is limited to about 12". Just use a phototransistor to read and a IR led
> to write to the Hp48 using normal (8,N,1) serial com. (2400baud max). Matt

1998\12\01@151815 by Lynx {Glenn Jones}

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Im almost positive that the HP doesnt use IrDA, theres been quite a bit of
talk about this on the comp.sys.hp48 newsgroup. But since i dont know what
IrDA is exactly, i cant say for certain. I think that if you have a laptop
that uses IrDA, you can configure the laptop to talk to the HP, but thats
about as much as i know.

------------------------------------------------------------------------------
A member of the PI-100 Club:
3.1415926535897932384626433832795028841971693993751
058209749445923078164062862089986280348253421170679

On Tue, 1 Dec 1998, Goovaerts wrote:

> This infrared that you use, does it implies the IrDA standard ?? Because I
> have to implement IR following IrDA on a PIC16C63 !! If somebody sends you
> some code, can you forward it to me ??
> Thanks and greetings from Glenn Goovaerts !!!
>
> {Original Message removed}

1998\12\01@153917 by Dennis Merrill

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I am pretty sure that the HP does not speak IrDA. It is simply a serial IR
link. Making the calculator speak IrDA would have been overkill for this
application, as it was not meant to have multiple connections. For info on
the HP, check out http://hp48.wsjr.com - I'm sure you can find the timing
diagrams and a description of the IR protocol there. Best of luck!

At 11:26 AM 12/1/98 -0800, you wrote:
>> >Does anyone have info on the serial protocol that HP uses to implement
>> >their infra-red serial interface - for calculators and palmtops.


-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Dennis Merrill, BSEE         work: .....merrillKILLspamspam.....nicolet.com
Firmware Engineer            home: EraseMEmerrillspam_OUTspamTakeThisOuTieee.org
Embedded Systems Group
Nicolet Instrument Corp.    phone: 608.276.6136

web: http://www.geocities.com/ResearchTriangle/5256
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

1998\12\01@160307 by Lynx {Glenn Jones}

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Kermit is the file transfer protocal it uses, but it can also send
characters as raw ascii. I hope you can understand what im saying here.

------------------------------------------------------------------------------
A member of the PI-100 Club:
3.1415926535897932384626433832795028841971693993751
058209749445923078164062862089986280348253421170679

On Tue, 1 Dec 1998, Gael Waiche wrote:

{Quote hidden}

ed
> > to write to the Hp48 using normal (8,N,1) serial com. (2400baud max). Matt
>

1998\12\02@172501 by jmnewp

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Yea, I'm doing similar communication with the HP and my current
project.  It does NOT only know the kermit protocal, it may also use
asynchronos serial communication, at least through the wired port, I'm
not sure if it works with the IR port though.  The XMIT command sends a
string on the first level of the stack, the SRECV command takes the
number off of level one of the stack and receives that many characters
in the buffer, I've got some more prgramming info if you'd like it.  as
I just read in one of the replies, the IR port is also inverted so that
would require it to always be on (which would drain a bunch of power) in
an asychronos state of affairs, correct me if I'm wrong on that....


Jon

Don Holtz wrote:
{Quote hidden}

1998\12\02@185018 by Lynx {Glenn Jones}

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Works with both the IR port and the Wired port. also, it is inverted, that
is IR on means 0, but this doesnot take extra batt power because to start
sending, its sends an initial 0 to get things rolling.

------------------------------------------------------------------------------
A member of the PI-100 Club:
3.1415926535897932384626433832795028841971693993751
058209749445923078164062862089986280348253421170679

On Wed, 2 Dec 1998, MARK D NEWPORT wrote:

{Quote hidden}

1998\12\04@121258 by Jurva-Markus Vehasmaa
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You micht be interestet on Maxims MAX3100 uart. http://www.maxim-ic.com
It suports IrDA protocol.


----------
From: Goovaerts <@spam@goofy1KILLspamspamGLO.BE>
To: KILLspamPICLISTKILLspamspamMITVMA.MIT.EDU
Subject: Re: Interfacing a PIC to HP infra-red serial port.
Date: 1. joulukuuta 1998 17:34

This infrared that you use, does it implies the IrDA standard ?? Because I
have to implement IR following IrDA on a PIC16C63 !! If somebody sends you
some code, can you forward it to me ??
Thanks and greetings from Glenn Goovaerts !!!

{Original Message removed}

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