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Posted to dev@nuttx.apache.org by Sebastien Lorquet <se...@lorquet.fr> on 2022/12/09 10:21:53 UTC
Port to M5Stamp-C3U
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
The module does not use a usb serial chip but direct USB connection
(there is a schematic in the bottom of the page).
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?
I ask this dumb question here because I know there are ESP32 people on
this list.
Thanks for the help,
Sebastien
Re: Port to M5Stamp-C3U
Posted by James Dougherty <ja...@gmail.com>.
That's sweet! I am updating an existing design from
ESP32-WROOM-32U-N4/platformio to ESP32-S3-WROOM-1U-N16/nuttx
so I got this new S3 board -
https://www.mouser.com/ProductDetail/356-ESP32S3DEVKTM1N8
I will have to try it out! Thank you!
On Fri, Dec 9, 2022 at 6:17 AM Sebastien Lorquet <se...@lorquet.fr>
wrote:
> (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 <se...@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
>
Re: Port to M5Stamp-C3U
Posted by Sebastien Lorquet <se...@lorquet.fr>.
(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 <se...@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
Re: Port to M5Stamp-C3U
Posted by "Alan C. Assis" <ac...@gmail.com>.
Hi Sebastien,
On 12/9/22, Sebastien Lorquet <se...@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
Re: Port to M5Stamp-C3U
Posted by Sebastien Lorquet <se...@lorquet.fr>.
Hi,
OK I got the bootloading part figured out (eg, it shoud work because the
esp32c3 has a serial bootloader mode in ROM that should support usb CDC,
and I see a serial port by pushing the GPIO9 button while plugging it
in), I will try to use my board as a esp32c3 devkit for now, it shoud be
similar.
(later)
So the esp32c3-devkit:usbconsole configuration works on the m5stamp-c3u.
nsh> uname -a
NuttX 10.1.0-RC1 512be93c36 Dec 9 2022 12:32:21 risc-v esp32c3-devkit
Nice.
Sebastien
Le 09/12/2022 à 11:21, Sebastien Lorquet a écrit :
> 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
>
> The module does not use a usb serial chip but direct USB connection
> (there is a schematic in the bottom of the page).
>
> 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?
>
> I ask this dumb question here because I know there are ESP32 people on
> this list.
>
> Thanks for the help,
>
> Sebastien
>