Currently purchased with the STEVAL-SMARTAG1, it was discovered that the capability collected through the ST25 powers the L0 via EH pin VDD while collecting data from the sensor. I need to collect signals by thermocouple, which is the same transmission mode as SPI. Can I successfully collect data in this way? Any better suggestions?
the EH pin provides a very limited current and a very unstable voltage. Therefore, an LDO is used to stabilize the voltage to the MCU to 1.8 V. The thermocouple (such as the MAX6675) requires higher operating voltage (3.0 V to 5.5 V) and an higher current than that the ST25 is able to provide.
Yes, where VDD can wake up the mcu, but can not meet the MAX6675 requirements, then L0 has other 3.3v voltage? Can I design a voltage pin with a 3.3v output from the VDD voltage?
