Timer 1 Problem

[SLF]

We created a temperature datalogger with a PIC 18LF2550.

My problem is that they don't work with cold temperatures.

Now I put a external rectangular clock (0 to 3.6V / 32.768kHz) into the RC0/T1OSO/T13CKI Pin (T1OSO is not connected) with the T1CON configuration 10110111b.
When I make that, then the Voltage of the clock goes down to 200mV and there is no timer 1 interrupt to wake up the PIC from sleep. I think it must be connected with the T1OSCEN, because when I enable the T1OSCEN and change the clock input to T1OSO then it works, but not with cold temperatures.

Can anyone help me to find the right configuration?

Here's my Timer 1 configuration routine:

[ckielstra]

Have a look at figure 12-1 of the PIC18F2550 datasheet for an explanation of the timer1 internal circuitry. Especially read Note 1 at the bottom of this figure.
You have to connect the external clock to the T1OSO pin and by clearing the T1OSCEN bit you can save a little energy.

What is the version number of the compiler you are using? You can find this at the top of the list file (*.lst).

What is the brand and type number of you external oscillator?

You say it doesn't work at cold temperatures. How cold?
The Large Hadron Colider had some problems last week. This is working at temperatures around 2 Kelvin. Is this the project you are working on?

[SLF]

No this is not the project I'm working on. It's for a Miniature Scientific Temperature Datalogger.

But it works now, also with cold temperatures (up to -40°C). I had a really stupid error.

When I initialised my pins for sleep mode I set pin T1OSO low.
This was in a subroutine at the end. So I didn't find it promptly.