Are Series 2 Tivo remotes JP1 compatable?

Foxx · Post by **Foxx** » Tue Jan 13, 2004 10:37 am

I'm not too new to the whole i2c and serial EEPROM world, however I haven't done anything pratical with them as of yet. So when people started mentioning EEPROMS, I'm not all too stupid. As for the JP1 community, I'm as new as they get. I have been trying to figure if the JP1 hardware is compatable with my Series 2 Tivo remote. The main EEPROM is a Microchip 24C02 1K serial EEPROM. Now, I notice that the JP1 hooks onto a reset line that i cant find. How important is it to hook into? Does anyone know how to hook the JP1 into this specific remote? Or better yet, is it compatable (im assuming it is)? Now, i know the SCL and SDA are pins 5 and 6 on the IC, and if you cant find VCC and VSS you really shouldnt be trying this, but like i stated before, i have no idea where the reset pin to the main MCU is. I cant even identify who makes it...

johnsfine · Post by **johnsfine** » Tue Jan 13, 2004 10:54 am

RESET is less important than the three major signals SDA, SCL and ground.

In theory the MCU might interfere with external control of SDA and SCL unless you hold it reset. In practice it usually doesn't.

If you use JP1 without batteries in the remote, you might need to provide power for the eeprom chip, but in practice we usually find that there is enough capacitance on the power line to use JP1 without batteries (When either SDA or SCL is higher than the power line, it both works correctly as a high signal and charges the power capacitance. When both SDA and SCL are low, the capacitance powers the chip).

I expect you'll find that the EEPROM is compatible (IR.EXE can read and write raw eeprom data once properly connected) but the contents are not compatible (no RDF exists, nor could an RDF be created, since we make some basic assumptions about how the eeprom contents are used).

Foxx · Post by **Foxx** » Tue Jan 13, 2004 11:38 am

Are you saying that i cant create my own RDF's at all, or just that the ones that are allready out there wont be compatable because of the different EEPROM type? there aremaybe at most 6 buttons i would liek to remap. My main problem however is that my tivo remote maps the wrong keys to the tivo remore (TV power brings up MENU, and PIP brings up captions). I want to remap the data so its all in the right places.

Post by **The Robman** » Tue Jan 13, 2004 12:01 pm

If your remote is indeed a UEI remote, you might be able to use keymover to re-program those buttons, even without JP1.

We have come across remotes before where the RESET line wasn't exposed, and it was for this reason that Tommy Tyler (our hardware expert) invented what we call the "stereo interface". Basically, we use a stereo headphone adapter and cut the traces to the SDA and SCL pins of the EEPROM, so when the headphone jack is empty, the EEPROM is connected to the MCU, but when you insert the JP1 jack into the headphone socket, it breaks the SDA and SCL connections. (More on this in the hardware folder).

If the remote is a UEI remote and you are able to hook up a JP1 connection, we should be able to create an RDF for it. However, that 24C02 chip is too small to be of any use to you at all, you will need to replace it with at least a 1k chip (24C08) but you might as well use a 2k chip (24C16). Hopefully, the remote is programmed to become upgradeable when it detects a larger chip onboard.

Foxx · Post by **Foxx** » Tue Jan 13, 2004 12:23 pm

Ive attached some really small 36 guage wire to the SDA, SCL, VCC and VSS pins. Im going to try and get the EEPROM itself hooked to the PC, and use an external power source, that way the remote MCU is not powered, and im going to slap together a JP1 interface and see what happens. Another quick question... can IR.exe read *any* serial eeprom? Cause i have some other projects that involve manipulating serail eeproms, but i cant find any hardware/software for a reasonable price.

Foxx · Post by **Foxx** » Tue Jan 13, 2004 12:25 pm

I forgot to add, as long as i can get TV power, Volume up/down, Mute, and the PIP button remaped to captions, ill be a happy camper.

Post by **The Robman** » Tue Jan 13, 2004 12:36 pm

It should be able to, try it and see.

Foxx · Post by **Foxx** » Tue Jan 13, 2004 12:37 pm

BTW, whats a UEI remote? I havent cought onto that meaning yet...

Post by **The Robman** » Tue Jan 13, 2004 12:59 pm

UEI = Universal Electronics Inc

They're the people who make all JP1 remotes, regardless of the brand.

Foxx · Post by **Foxx** » Tue Jan 13, 2004 1:10 pm

what if my remore is NOT made by them, could it still be JP1 compatable?

Post by **The Robman** » Tue Jan 13, 2004 4:36 pm

johnsfine · Post by **johnsfine** » Tue Jan 13, 2004 4:41 pm

Foxx wrote:what if my remore is NOT made by them, could it still be JP1 compatable?

As I said before, it might be hardware compatible, able to read and write raw eeprom data.

It wouldn't be compatible enough for IR.EXE to know what to change in the raw data to change any specific behavior of the remote.