Porting problem for wifi Ampak AP6356 PCIE interface


We meet problem when porting wifi Ampak AP6356.
The interface is PCIE interface.

It is known that the voltage level of the RST signal must be obtained 1.8V at the high level for the CPU of the PCIe interface.

The RST signal close to the CPU side with the open terminal to be measured, which is obtained the voltage level is lower than 1.8V at the high level as the following figure for our layout of the board.

We want to understand any chance can implement the voltage level to reach 1.8v?

The following is the measured result for your reference.

Hi, what’s the value you measured? Basically, the voltage level has +/-5% tolerance.

The voltage is measured about 0.9~1V close to CPU with open terminal.

Which RST you mean, the PEX_L0_RST_L or PEX_L1_RST_L? They are in VDDIO_PEX_CTL block which voltage should be 3.3V as you can see in reference schematic.

The RST means PEX_L0_RST_L.

The voltage should be 1.8v, right?

It’s 3.3v default. Please check the input voltage level of VDDIO_PEX_CTL pin.