HTCC-AM02 Will Only Start When Serial Monitor Opened

#1

Hi All,

Any ideas what would cause this?

The circuit I have created uses the Heltec recommended auto boot components and CP2102 USB-UART controller.

Program loaded runs absolutely fine once I’ve connected via USB and opened serial monitor in Arduino IDE. Carries on running even if USB disconnected. Just won’t start up without connecting via USB and opening serial monitor.

Many thanks in advance.

#2

Update: Resolved
I had put a 2.2nf capacitor from reset to gnd rather than 2.2uf.

#3

This looks very good.

#4

Hello lofty, I was wondering if you could share your pcb schamtics? Im looking at using the HTCC-AM02 and can figure it out.

#5

Use this reference design from heltec to get started

Make sure you use a CP2102 not the newer CP2102N (it doesn’t work from my experience)