Issues with CP2102N in custom board
Posted: Thu Jan 11, 2018 8:40 pm
Hello! I'm working on a custom board that uses the CP2102N to communicate with the ESP-WROOM-32 and am having some issues with the prototype. I followed the schematic in the attached core board document.
Differences include:
- use of the CP2102N instead of the CP2102, which is a drop-in replacement
- lack of connection of the CTS and RTS pins to the ESP32
- EXT_5V is connected to an internal 5V rail instead of the USB 5V. The board is powered from a source other than USB, and I read that there are issues if both are connected (the chip can heat up and destroy itself)
- nothing used from the SWITCH BUTTON section
- nothing used from Power Supply section, since we have our own power supply for the rest of the board
I thought the transistor network was the issue, so I bypassed them completely by directly connecting DTR to IO0 and RTS to EN. This seemed to put the ESP32 in bootloader mode, but make flash would not work:
My setup is an Ubuntu VM on Windows 10. Drivers installed for both operating systems and the device correctly shows up in device manager, though, it occasionally shows an error stating that the device is not working properly or that it failed to start. I can successfully flash an ESP32 on a known working board without issues in this same setup, so I highly suspect that the issue is with the way the CP2102N is wired on my custom board.
Any help is greatly appreciated! I've already spent 10-15 hours attempting to debug this, hooking up a logic analyzer to check the EN and IO0 states, reworking the board to bypass transistors, etc. I wouldn't be surprised if I'm just missing something simple (like if the EXT_5V pin must be hooked up to the USB socket or if it's fine connected to a separate 5V rail). Thanks ahead of time!
Differences include:
- use of the CP2102N instead of the CP2102, which is a drop-in replacement
- lack of connection of the CTS and RTS pins to the ESP32
- EXT_5V is connected to an internal 5V rail instead of the USB 5V. The board is powered from a source other than USB, and I read that there are issues if both are connected (the chip can heat up and destroy itself)
- nothing used from the SWITCH BUTTON section
- nothing used from Power Supply section, since we have our own power supply for the rest of the board
I thought the transistor network was the issue, so I bypassed them completely by directly connecting DTR to IO0 and RTS to EN. This seemed to put the ESP32 in bootloader mode, but make flash would not work:
Code: Select all
nick@ubuntu:~/esp/test$ make flash monitor
Flashing binaries to serial port /dev/ttyUSB0 (app at offset 0x10000)...
esptool.py v2.1
Connecting........
Traceback (most recent call last):
File "/home/nick/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 2524, in <module>
_main()
File "/home/nick/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 2517, in _main
main()
File "/home/nick/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 2247, in main
esp.connect(args.before)
File "/home/nick/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 368, in connect
last_error = self._connect_attempt(mode=mode, esp32r0_delay=True)
File "/home/nick/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 329, in _connect_attempt
self._port.setDTR(True) # IO0=LOW
File "/usr/lib/python2.7/dist-packages/serial/serialutil.py", line 547, in setDTR
self.dtr = value
File "/usr/lib/python2.7/dist-packages/serial/serialutil.py", line 411, in dtr
self._update_dtr_state()
File "/usr/lib/python2.7/dist-packages/serial/serialposix.py", line 605, in _update_dtr_state
fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_DTR_str)
IOError: [Errno 32] Broken pipe
/home/nick/esp/esp-idf/components/esptool_py/Makefile.projbuild:54: recipe for target 'flash' failed
make: *** [flash] Error 1
nick@ubuntu:~/esp/test$ make flash monitor
Flashing binaries to serial port /dev/ttyUSB0 (app at offset 0x10000)...
esptool.py v2.1
Connecting........_____....._____....._____....._____.....
Traceback (most recent call last):
File "/home/nick/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 2524, in <module>
_main()
File "/home/nick/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 2517, in _main
main()
File "/home/nick/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 2247, in main
esp.connect(args.before)
File "/home/nick/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 368, in connect
last_error = self._connect_attempt(mode=mode, esp32r0_delay=True)
File "/home/nick/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 330, in _connect_attempt
self._port.setRTS(False) # EN=HIGH, chip out of reset
File "/usr/lib/python2.7/dist-packages/serial/serialutil.py", line 544, in setRTS
self.rts = value
File "/usr/lib/python2.7/dist-packages/serial/serialutil.py", line 401, in rts
self._update_rts_state()
File "/usr/lib/python2.7/dist-packages/serial/serialposix.py", line 600, in _update_rts_state
fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_RTS_str)
IOError: [Errno 32] Broken pipe
/home/nick/esp/esp-idf/components/esptool_py/Makefile.projbuild:54: recipe for target 'flash' failed
make: *** [flash] Error 1Any help is greatly appreciated! I've already spent 10-15 hours attempting to debug this, hooking up a logic analyzer to check the EN and IO0 states, reworking the board to bypass transistors, etc. I wouldn't be surprised if I'm just missing something simple (like if the EXT_5V pin must be hooked up to the USB socket or if it's fine connected to a separate 5V rail). Thanks ahead of time!