William Lucid asked 4 months ago
There is a solution; use a 74HC04N, six pack of inverter/buffers; use a pair of inverters for a HIGH input and and a HIGH out or if you need the inverted polarity use a single inverter. Simply route from the non-RTC_GPIO wake up signal to the first inverter input. Output of first inverter connect to the input of second inverter. Output of second inverter is routed to RTC_GPIO that is externally wake up capable! –credit goes to Microsoft’s Copilot for the fix.
William, AB9NQ
William Lucid answered 3 weeks ago
ESP32.com forum user pointed out that you can do not need the 74HC04. Claude summarized the method:
Good point! You actually don’t need to cut the trace in most cases.
Simpler Approach – Just Add a Wire
You can simply:
- Wire DIO1 to an RTC GPIO pin (like GPIO16) in addition to the existing GPIO33 connection
- Configure the RTC GPIO for wake-up in your code
- Leave GPIO33 alone (or just don’t use it in your code)
No trace cutting required! Both pins can be connected simultaneously since:
- The SX1262 DIO1 is an output pin driving the signal
- Both ESP32 GPIO pins are inputs (high impedance) when configured for wake-up
- There’s no conflict having multiple inputs listening to the same signal
When You Might Cut the Trace
You’d only need to cut the GPIO33 trace if:
- You want to repurpose GPIO33 for something else entirely
- There’s some electrical interference or conflict (unlikely)
- You’re being very particular about minimizing current leakage (minimal benefit)
But for the typical use case of just enabling LoRa wake-up from deep sleep, just add the jumper wire and configure your code to use the RTC-capable GPIO. Much simpler!
Thanks for catching that – no need to make permanent PCB modifications when a simple wire addition does the job.
William