HTCC-AM02 PCB design RESET button and bootloader mode via RTS/DTR

#1

Hi all, I tried to implement the reference Arduino design for the HTCC AM02 and so far nearly everything works fine. I found however that neither the reset button nor “automatic” bootloader (aka flash) mode via serial is possible. Could someone give me some advice?

It is possible to press both RESET and USR1 button on startup to enter the bootloader mode and firmware flashes fine. However I thought it’s also possible to do this automatically via a RTS or DTR pin?

Schematic_htcc-am02-dev-board_2021-10-12
Schematic_htcc-am02-dev-board_2021-10-12.png2338×1654 482 KB

It’s designed with EasyEDA, if someone is interested in the PCB/Schema files I’ll upload them somewhere

#2

What serial chip do you use to download the program?

#3

I’m using a FTD1232 but I’m happy to switch to whatever else would make it work.

#4

Did you connect the DTR and RTS pins? If FTD1232 doesn’t work, you can try CP2102, and you need to connect DTR and RTS pins.

#5

Thanks for your quick response. I connected both DTR->DTR and RTS->RTS but it doesn’t work. I’ll try to get the CP2102 chip.

#6

Hi @aparcar, I made a custom PCB based on AM02 module. I wanted a solution with minimal components number, I used an external USB UART/TTL for flashing my device and I only integer a reed switch (instead of a button) for Reset.
I shared my newbie schematics (kicad) on https://discord.gg/WTudFKas
Feel free to join, maybe we can share our BOM because I made my PCB on Jlcpcb too.

1 Like
#7

Hi @AlexFR,
I am interested in a solution with an external USB converter.
Have you already finished your PCB and verified its functionality?
Can you share schematics here, discord.gg link is not valid, it has expired.

#8

Hello Alex
I was wondering if you could share your schematics. Im trying to build a sensor for my garden using the AM02 chip

#9

Hello, I think I share schematics in another post. What type of sensors do you want to use ? I just buy a Power Profiler Kit II from nordic semi to test power consumption during deep sleep. I want to compare the heltec official dev board versus my pcb. Maybe schematics will change. I’m on discord if you want AlexFR#2921