jurjen@cwi.nl (Jurjen NE Bos) (06/04/91)
About once a week, we get a request to convert our HP28 remote control program
to the HP48. We have not succeeded in doing this yet.
The main reason that we did not succeed, is that the proper way to control the
hp48's IR LED has not been found.
A while ago somebody posted that bit 3 of address #11C controls the LED, but
this is not useable for a remote control for two reasons:
- The LED is turned on unmodulated, while a remote control needs a 30kHz
modulated signal to work properly. (Actually, I wrote a remote control
program using unmodulated signals, and it works over 6 cm, no more.)
- The LED is not always turned on if the bit is set, so that the resulting
program has unpredictable behaviour. There is probably a disabling
circuit that we do not know of.
Does anybody know where this bit is? Please let us know.
On the HP28, there is a single bit that turns the LED on, modulated and all;
we hope that there is a correponding bit on the HP48.jmauric@hubcap.clemson.edu (Phantom of Adexsi) (06/07/91)
From article <3632@charon.cwi.nl>, by jurjen@cwi.nl (Jurjen NE Bos): > About once a week, we get a request to convert our HP28 remote control program > to the HP48. We have not succeeded in doing this yet. > > The main reason that we did not succeed, is that the proper way to control the > hp48's IR LED has not been found. > A while ago somebody posted that bit 3 of address #11C controls the LED, but > this is not useable for a remote control for two reasons: > - The LED is turned on unmodulated, while a remote control needs a 30kHz > modulated signal to work properly. (Actually, I wrote a remote control > program using unmodulated signals, and it works over 6 cm, no more.) re: 6 cm. cant you buy an IR booster and have it work for distances more than 6 cm? can you send me the remote control program via email? > - The LED is not always turned on if the bit is set, so that the resulting > program has unpredictable behaviour. There is probably a disabling > circuit that we do not know of. -- =============================================================================== !X! File Edit Tools Special Guru 999999999 Bytes Free =============================================================================== ABench1.3> JMAURIC@HUBCAP.CLEMSON.EDU .. John Maurice .. (803)-653-8302