suitable crystal
Posted: Tue Dec 24, 2019 8:12 pmI have trouble with following crystal for my ESP8266 board:
https://lcsc.com/product-detail/SMD-Osc ... 27551.html
The sine wave was only 20mV pp. So I cut the XTAL_IN trace and connected the crystal directly to 3.3V (with a 3.6K resistor) and that lets me connect to the serial port with 74800 baud. The Vmax of the sine wave is ~1V now. (1.36V without the resistor)
Checking XTAL_OUT, it provides only 840mV, which does not seem to be enough for this particular one (~1.7-3.3V). Using a crystal from a random ESP8266-01 donor board works as well with the expected ~800mV sine wave.
Vpp seems ~700-800mV in both cases.
The datasheet unfortunately does not tell anything about the voltage required and does not list suitable crystals. Not sure if my resistor botch has any side effects or may cause damage to the chip long term cause of the higher voltage at XTAL_OUT
https://lcsc.com/product-detail/SMD-Osc ... 27551.html
The sine wave was only 20mV pp. So I cut the XTAL_IN trace and connected the crystal directly to 3.3V (with a 3.6K resistor) and that lets me connect to the serial port with 74800 baud. The Vmax of the sine wave is ~1V now. (1.36V without the resistor)
Checking XTAL_OUT, it provides only 840mV, which does not seem to be enough for this particular one (~1.7-3.3V). Using a crystal from a random ESP8266-01 donor board works as well with the expected ~800mV sine wave.
Vpp seems ~700-800mV in both cases.
The datasheet unfortunately does not tell anything about the voltage required and does not list suitable crystals. Not sure if my resistor botch has any side effects or may cause damage to the chip long term cause of the higher voltage at XTAL_OUT