EEVblog® Electronics Community Forum
Electronics => Microcontrollers => Topic started by: anfractuosity on June 13, 2020, 10:45:05 am
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Hi,
I'm just wondering, if anyone might be able to give me any suggestions for the attached circuit.
I've just had a PCB made, which I've now got, which is failing to connect with esptool, I get 'Timed out waiting for packet header'
I noticed I didn't have a pullup on GPIO0 which I've now added, but I still get the same issue alas.
I've measure the voltages from the transistors attached to RTS and DTR, and with the pull up, they appear to give the same desired voltages
as what is mentioned in the esptool.py source code.
I also tried holding a 10uF cap against EN and GND, to no avail, while running esptool.
The pcb photo is before adding the bodge pullup resistor for GPIO0
Any pointers would be much appreciated!
The following is the code I created and measured the voltages of en and gpio0, with the bodge resistor in place:
#!/usr/bin/python3
import time
import struct
import serial
ser = serial.Serial('/dev/ttyUSB0',baudrate=115200,timeout=None) # open serial port
while True:
ser.dtr = True
ser.rts = True
# gpio=3.3 en=3.3
#while True:
# ser.dtr = False
# ser.rts = True
# gpio = 3,3 en = 0
#while True:
# ser.dtr = True
# ser.rts = False
# gpio = 0 en = 3.3V
#while True:
# ser.dtr = False
# ser.rts = False
# gpio = 3.3 en = 3.3
I'm wondering if it's correct that if both dtr & rts are false or true, that gpio is 3.3 and en is 3.3V?
I just measured :
The tx pin of the esp32 seems to always remain = 3.3V
vddsdio pin of the esp32 seems to remain = 0V (which I believe means it's not booting?)
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Have you probed the board with a scope to see if there any activity on TX when it comes out of reset?
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I have spent quite a while checking over the footprints and orientation, but will look at this again.
From what I can tell the TX remains high constantly, but will have another look.
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blueskull - Thank you so much! Doh! Can't believe I didn't spot this before.