(Note that I did write "use" not port :p)
I got it working very fast by reading all the provided docs! This was
very well made this time, the level of support for this chip is very pro.
I could even recompile the required second stage bootloader from source.
It's fun that this bootloader requires a riscv32 toolchain whereas nuttx
is compiled with another riscv64 toolchain!
All that would remain to do is write a board config for the name
"m5stamp-c3u" instead of "esp32c3-devkit" but I'm too lazy for that,
sorry :p
Sebastien
Le 09/12/2022 à 13:14, Alan C. Assis a écrit :
Hi Sebastien,
On 12/9/22, Sebastien Lorquet <sebast...@lorquet.fr> wrote:
Hi,
As an introduction to the RISCV, I would like to use NuttX on my M5stamp
C3U, which I can get for 8 dollars at a local store.
https://docs.m5stack.com/en/core/stamp_c3u
This M5stamp C3U uses that ESP32-C3 that is already completely
supported on NuttX.
So, if your plan was to do a port, you arrived too late in the party :-D
The module does not use a usb serial chip but direct USB connection
(there is a schematic in the bottom of the page).
The USB serial on ESP32-C3 is already support on NuttX mainline too.
I wonder how it works: Is serial on USB supported by an internal
bootloader or does this require firmware support that will disappear
after I flash this board for the first time?
It doesn't require a firmware and normally will not require a host
driver because it is a generic USB CDC Serial internal.
Espressif create a nice thing that all MCU should have: a USB Serial /
JTAG internally integrated in the chip.
So, you don't need an external programmer neither an external
USB/Serial. Just a USB cable and you can program the chip and get a
console interface.
You can get more info about it reading the "USB Serial/JTAG
Controller" chapter of the ESP32-C3 TRM.
BR,
Alan
