TX1 Power up sequence using a microcontroller, CARRIER_PWR_ON signal

Hi, i am having some problems when trying to power on the TX1 on my custom carrier board.
I did not find in the data sheet, OEM design guide of this forum an answer.

I did not connect the CARRIER_PWR_ON signal to the microcontroller, and the TX1 turns on using the power up sequence, even though the 1.8V in the carrier board is active before the TX1 is on.

but it would not turn on every time, sometimes it would not turn on even though the sequence is the same.

so, i have few question:

  1. in my case the carrier board must be on before the TX1, in the OEM it says that the TX1 must be on before the carrier board powers up, what will be the right way to power up the TX1 in this case ?

  2. There is a 10k pull up to a 1.8V only to the RESET_OUT pin (A46), so almost no current goes into this pin, in this case is it possible to have the 1.8V turn on first on the carrier board, or this is a no-go condition ?

  3. Does the CARRIER_PWR_ON signal that outputs from the TX1 is relevant for the power up sequence or is it used only for the carrier board 1.8V enable ?

  4. when TX1 is powering up, and the carrier board is already up, and the I/O pins on the TX1 has voltage on it but no current goes into the pins, would it fail the powering up of the TX1 ?

than you

Hi, please totally follow the power up sequence as listed in figure 4 in OEM DG. Module power rails should be on before CARRIER_PWR_ON. We don’t have any suggestion for the design that violates that.