Hi Ateş,
The FXTH87 can transfer information to another MCU using software SPI or software IIC, as there is no hardware SPI or C block in the FXTH87.
There are several ways to trigger the Pressure/Temperature measurement and SPI/IIC transfer: for example, it can be triggered by a periodic wake up using the FXTH PWU block or by an external signal triggering an interrupt on a FXTH GPIO (using the KBI block of the FXTH87). However, currently there is no code example/document illustrating this available.
Best regards,
Tomas