12 Feb 91 01:18N PERSONALNAME: HP48SX Unified Remote Control
I am posting this for a friend... Since I don't make it onto this newsgroup
very often, please mail source code directly to this account as well as
posting to handhelds. Thanks!
Begin...
I am trying to locate a routine for the hp48sx which would be capable of
transmitting IR commands to a tv. Has anyone written such code? I have a
posting by Michiel Niemeijer & Eric Toone regarding controlling RC5 (PHILIPS
equipment) using the 28s. I could repost this if they are no longer on the
net. I would greatly appreciate such a routine, or at least guidance on
writing such a routine (necessary hooks etc...).
For those wishing to take up the challenge, here are a few more details about
my specific needs:
I want my HP48 to be able to transmit Thomson/RCA Unified Remote/Dimensia
ir codes. RCA ir commands are composed as follows:
____ _ ____
...| |____| |XXXXXXXXXXXXXXXXXXXXXXXX|____| |...
^ ^ ^ <+-><--+---><+-><--+---> ^ ^
| | | | | | | | |
| | | | | | | | +- Mark of next
| | | | | | | | transmission.
| | | | | | | |
| | | | | | | +- Repeat Space = 8 mS
| | | | | | | _______
| | | | | | +- 8 bits (COMMAND)
| | | | | | ________
| | | | | +- 4 bits (PREAMBLE)
| | | | |
| | | | +- 8 bits (COMMAND)
| | | |
| | | +- 4 bits (PREAMBLE)
| | |
| | +- SYNC = .5 mS
| |
| +- SPACE = 4 mS
|
+- MARK = 4 mS
Namely, a MARK consisting of a logic 1 for 4 mS followed by a SPACE consisting
of a logic 0 for 4 mS, followed by a .5 mS logic 1 SYNC pulse, followed by a 4
bit PREAMBLE and an 8 bit COMMAND. The PREAMBLE and COMMAND are both
complemented and retransmitted. Finally a repeat SPACE of 8 mS is inserted
between transmissions.
Where,
1mS ___
A logic bit "1" ==> ______| |
.5mS
2mS ___
A logic bit "0" ==> ____________| |
.5mS
with a carrier frequency of 56.875 kHz (Period = 17.58 uS). Therefore
transmission lengths are ALWAYS the same (56.5 mSec). Although the HP uses a
carrier frequency of 32.768 kHz (I think), the HP should still work assuming
it is placed within a couple of feet of the tv/vcr/etc..
The PREAMBLE denotes the device:
PREAMBLES
===================
TV 0
VCR1 1
VCR2 2
AM/FM 3
etc..
I don't have time to type in all the COMMANDs, but here are a couple for
testing purposes.
COMMAND (hex)
==================
ON C5
OFF C4
MUTE ON D9
MUTE OFF DA
CHANNEL UP D2
CHANNEL DOWN D1
The possible uses for such a routine and the software that could easily be
built around it is virtually endless.
Couple of simple examples:
- a single remote for different pieces of equipment simply by changing the
current keymap.
- resetting of the tv/vcr time & date after a power failure with a single
keypress.
- use of the calculators timer abilities to program shows or to add this
capability to primitive vcrs.
Although the ir commands for many tvs and vcrs are different, most are easily
accessible. If someone would be kind enough to provide the machine code to
send a single transmission described above, I would be willing to write some
truly useful programs, as well as provide the remainder of the ir commands.
*** Caution ***
Since it is possible to erase tapes, reinitialize the tv's eeprom to factory
settings, possibly lock something up, etc., EXPERIMENT AT YOUR OWN
RISK. No assurances of performance or usability are neither expressed
or implied.
Aaron D.
===============================================================================
Disclaimer:
The above in no way reflects the opinions, beliefs, policy, or actions of my
employer, Thomson Consumer Electronics (TCE).
===============================================================================
End...
Rick McTeague
Electrical Engineering Department, Speed Scientific School
University of Louisville, Louisville, KY 40292
(502) 588-7020
RAMCTE01@ULKYVX (Bitnet)
RAMCTE01%ULKYVX.BITNET@CUNYVM.CUNY.EDU (Internet)
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