More info here: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/366759/am335x-rmii-direct-connection-between-two-devices
Same TI guy who said it was impossible latter talk internally and discovered that there was a customer already using it. BTW, you will need to have RMII supported by both MCUs (yes, ESP32 has RMII). BR, Alan On 10/29/22, Alan C. Assis <acas...@gmail.com> wrote: > Hi Tim, > > I just searched if it was possible to connect two Ethernet MAC > directly without using PHY and it is possible, so it will not involve > cost for you: > > https://stackoverflow.com/questions/39503466/can-two-ethernet-mac-chips-be-connected-directly-without-going-thru-phy > > BR, > > Alan > > On 10/29/22, Tim Hardisty <t...@jti.uk.com.invalid> wrote: >> Thanks for your clarifications Alan - I have messaged Espressif (your >> reply >> ended up in SPAM otherwise I might not have needed to) so I guess I'll get >> a >> similar answer. >> >> There is HCI (RCP) firmware for the SiLabs module so I can try that - >> it's >> the £7 per module saving of Espressif vs. SiLabs, plus getting WiFi for >> free >> that appeals. SAMA5D2 has Ethernet - unused on my board so it is not an >> idea >> that is completely out of the question: writing USRSOCK for the >> Espressif >> module is probably beyond me at this time! >> >> On 29/10/2022, 00:20, "Alan C. Assis" <acas...@gmail.com> wrote: >> >> Hi Tim, >> >> On 10/28/22, Tim Hardisty <t...@jti.uk.com.invalid> wrote: >> > Bit of a tangential question this, but I know there are folk on >> here >> who >> > are much more conversant with the way NuttX can be used with WiFi >> and >> > Bluetooth modules than I am. >> > >> >> I think these are important questions and other people could face >> similar issues in the future. >> >> > I may have an opportunity forced on me to have to respin my custom >> board >> > which currently has a SiLabs Bluetooth SoC as well as the main >> SAMA5D2 >> > processor. I used that module as I already have experience of it - >> but >> that >> > predates my NuttX journey. >> > >> > I see there are some very good value combined WiFi + Bluetooth >> modules >> now >> > (Espressif for example...and I know there's a well-known proponent >> of >> those >> > devices here lol) and, having seen a few other questions here, I am >> thinking >> > that I can go the HCI route and make use of the Bluetooth Stack in >> NuttX: >> > and add WiFi capability to my board at the same time. Winner! >> > >> >> First let me explain the differences: >> >> Espressif modules are not used as external modules on NuttX, >> everything is integrated inside the chip. >> >> During the WildernessLab's presentation on NuttX Workshop their team >> shown an ESP32 solution sharing WiFi as an external module. >> But they didn't use the default USRSOCK route, they implemented a new >> solution at home. >> >> > I'm hoping I can program up a suitable module with generic radio >> > co-processor software (HCI I think, and whatever is needed for >> WiFi) >> and >> > access it via UART from my main processor and have it all under the >> NuttX >> > system in a much more easily managed manner than a separate app on >> the >> > SiLabs SoC that just happens to communicate on some way with my >> main >> app on >> > the SAMA5D2. >> > >> > Have I got this right? Is an Espressif module a good choice (email >> me >> direct >> > if you want to !!)? >> > >> >> For Bluetooth (BLE) if there is a HCI firmware to SiLabs chip, then >> it >> could be possible to you use it, but you'll need to do some tests and >> debugging to get things working. >> >> For WiFi things are more complex because you need to implement a >> USRSOCK yourself to the chip. >> >> I never tested others possibilities: i.e. share Internet using SLIP >> between ESP32 and SAMA5D2, should be an easier route if it works, but >> of course you wil be limited to UART speed. >> >> Ethernet could be a better option (since ESP32 has Ethernet >> hardware), >> but it seems like an ugly and expensive workaround. >> >> BR, >> >> Alan >> >> >> >
