JP1 Remotes

If it matters I have:
HTPro (3rd one I'm trying to work with)
FileBug cable with 6' cable.
Latest software and new computer.

I'm having the following problems:
1) Remote is not learining properly/consistantly. I was not satisfied with an existing upgrade and some labels don't match button. Remote is not learning correct protical or claims unknow. I've tried about 5 time already. 3 learning buttons per 1 original button (to increase chances of sucess - only had about 1 out of 50 learned buttons work
I'm gonna change batteries in equip remote next.

2) Problems while cable connected to remote. LCD either has all the characters on at same time or remote is no-respondant with plug attached.
Problems with cable or remote? I tried two different HTPRO's in a row so i'm worried its the cable. [Sent email to tom at filebug and posting here]
Other possiblities?
Gonna reboot comptuer next...

suggestions or tips?

To clarify this is the 3rd one I'm attempting to program - First two had minimal problems.

1) Remote not learning very well. Even after repeated tries. *shrug*

2) Cable connection is acting up. One or more of the small wires may have been damaged. Any other reasons it would be acting up?

bob_m wrote: 2) Problems while cable connected to remote. LCD either has all the characters on at same time or remote is no-respondant with plug attached.

That symptom description isn't clear enough to understand what is happening or even whether it matters.

It may not matter what the remote's LCD does while the JP1 cable is connected or in use.

If the remote functions correctly as a remote while the JP1 cable connected (when not uploading or downloading) that can be very convenient for testing things. But if it doesn't, that isn't worth trying to fix.

The JP1 cable is for reading and writing the eeprom. If that's what you mean when you say "no-respondant" then it needs to be dealt with. But if uploading and downloading work, and something else doesn't, you should disconnect the JP1 cable for that something else.

Whatever the symptoms or problems, they are most likely an issue of battery voltage relative to the PC's printer port. Neither the remote nor the cable is likely to be at fault.

4-battery remotes most often work best (with JP1) with 4 low batteries. In rare cases new batteries or no batteries are best. For some PC's it doesn't matter at all, new batteries, old batteries, or no batteries all work fine. For other PC's you need to find what works.

Some people have found that reversing one of the four batteries (cutting 6 volts down to 3 volts) works well. If you try that, be sure to put it right again when you're done. Extended use with a reversed battery might make that battery leak.

Well I swapped batteries and even tried one of my other HTPro remotes.
All but 6 buttons are learned as NEC1, the last six are NECx1 no matter how many times I try
I posted a second question about 2 protocols in one remote in the newbie forum *shrug*

Thanksf for the info so far.

From that other thread, I conclude you're not having any battery problem nor any JP1 cable problem.

The NEC1 vs. NECx1 is an accurate representation of the VCR vs. DVD signals in your combo device.

johnsfine wrote:From that other thread, I conclude you're not having any battery problem nor any JP1 cable problem.

The NEC1 vs. NECx1 is an accurate representation of the VCR vs. DVD signals in your combo device.

Well techincally the JP1 cable upload/download is working. Just differently than last week with 2 different HTPro's.
*shrug*
Last week the remote worked (and learned) with the JP1 plugged in.
This week the remote doesn't do anything with the JP1 plugged in except upload/download. Oh well.

bob_m wrote:Last week the remote worked (and learned) with the JP1 plugged in.
This week the remote doesn't do anything with the JP1 plugged in except upload/download.

One of the signals inside a JP1 cable is called "RESET". That signal must be low during upload and download and must be high or disconnected when the remote is used (for learning signals etc.)

In a 4-battery remote, the PC can't raise that signal as high as it ought to be. For many combinations of PC and remote, it works anyway, even though the signal is technically too low.

In many cases it depends on the remote's batteries. To the best of my limited understanding of electronics, it ought to work better with lower batteries, because the PC's (printer port) voltage doesn't change while the threshold against which it is compared varies with battery voltage. Yet I've seen myself and seen reports from others showing RESET working with very new batteries and stopping working as the batteries get used. Of course we've also seen RESET do exactly the opposite, and work/fail in the expected correlation to battery voltage.

I don't think any of us have a good idea what is going on with the RESET signal. The buttom line is that getting RESET high enough (letting learning etc. work with the JP1 cable connected) isn't important enough to be worth the trouble of solving in those cases in which it proves to be trouble.

Question for our hardware Gurus:

Why do we use a resistor rather than a diode for the RESET signal? When we want RESET low, wouldn't the voltage drop across a diode be about the same as across the resistor, so the diode could pull RESET low enough? When we want reset high but the printer port doesn't go quite high enough, the voltage drop across the resistor would go down and across a diode it wouldn't go down. So a diode should pull RESET down as much as a resister does when we want it to, but less than a resister does when we don't want it to.

The resistor is there to limit current either way, to protect the port and the CPU/EEPROM in the remote. Enough current can pass to effect a logic 0 on the appropriate lines.

What would be the effect of doing it the way John suggests? (ie, using a diode instead of a resistor).

The diode would only prevent current flow in one direction. If you had, for example, a 6-volt remote connected to a 3.3-volt parallel port, the remote's reset line might never go above 3.9 volts, or possibly the remote's batteries would be able to fry the port by pulling the voltage well above 3.3 volts.