Which voltage levels correspond to the digital ones?
Posted: Sat May 11, 2019 10:24 pm
Hi!
To this moment I've used pre-made development boards for my project. But my current project requies a custom-made PCB. The ESP32 is on this board, as well as the auto-reset circuit and a USB-UART bridge for direct firmware uploading via USB. However, I overheated the auto-reset circuit transistors during the soldering, and they don't work quite well. By this I mean that when the ESP32 should be reset, the voltage on the EN line is 1.6V. That's enough for my logic analyzer to think it's a low level signal, but the ESP32 doesn't reboot with this voltage. The voltage on the GPIO0 when entering the boot mode is OK, but every time I want to upload a new firmware, I need to manually push the reset button in time.
Of course, I will fix the problem by replacing the faulty transistor, but that got me thinking about the voltage levels the ESP32 recognizes as logical high/low ones. In other words, what are the thresholds for the logical levels? I didn't find the information on the Internet. Maybe I just didn't search enough.
Thank you very much for any answer!
To this moment I've used pre-made development boards for my project. But my current project requies a custom-made PCB. The ESP32 is on this board, as well as the auto-reset circuit and a USB-UART bridge for direct firmware uploading via USB. However, I overheated the auto-reset circuit transistors during the soldering, and they don't work quite well. By this I mean that when the ESP32 should be reset, the voltage on the EN line is 1.6V. That's enough for my logic analyzer to think it's a low level signal, but the ESP32 doesn't reboot with this voltage. The voltage on the GPIO0 when entering the boot mode is OK, but every time I want to upload a new firmware, I need to manually push the reset button in time.
Of course, I will fix the problem by replacing the faulty transistor, but that got me thinking about the voltage levels the ESP32 recognizes as logical high/low ones. In other words, what are the thresholds for the logical levels? I didn't find the information on the Internet. Maybe I just didn't search enough.
Thank you very much for any answer!