But the RL872x MCU in the P2/Photon 2 is very cool:
2 MB user firmware binaries (up from 128K on the Photon/P1)
Lots more RAM available to user applications (exact amount to be determined)
Flash file system (2 MB)
200 MHz ARM Cortex M4F CPU
There is no pic available yet. The reason is that the P2 on the Photon 2 is wider than the 0.7" between the PTH headers on the Feather devices (Argon/Boron). There’s a special one-sided SMD male header pin strip that’s necessary on the bottom but we built pre-production samples with normal SMD headers, so samples are wider than a normal Feather, so the pictures aren’t representative.
I believe it’s three on both. It appears that the P2 datasheet and migration guide are missing two serial ports. There are three different UART peripherals, but for the 2nd and 3rd ports the pins are shared with SPI.
Q1 Is WPA2 Enterprise security going to be supported by the network stack or is this a continuation of Argon not having this support?
Q2 Will Photon2/P2 be able to support Ethernet adaptor like the Argon?
The nRF52840 is not being discontinued, but components in the Argon power supply are now end-of-life. Because the Photon 2/P2 have 5 GHz Wi-Fi support, enterprise Wi-Fi, and a much faster MCU, more flash, and more RAM, it made more sense to migrate the Argon to the Photon 2 rather than respin the Argon and have two competing Wi-Fi devices in the product line.
The Argon and Photon 2 Wi-Fi hardware is completely different.
The Argon has a separate ESP32 that implements Wi-Fi and an nRF52840 that handles the normal Particle stuff (cloud access, user firmware, etc.).
The P2/Photon 2 use a single Reaktek RTL8721DM MCU to handle both Wi-Fi and the Particle stuff.
However, TCP/IP is handled by LwIP on both the Argon and P2/Photon, so Ethernet switching will work in the same way. Which is to stay, not entirely automatically, though you could implement it in your firmware.
The problem with retained memory is that the similar feature on the RTL872x has a significantly smaller amount of space, and it’s not preserved across MCU reset, which kind of makes it useless. In some cases the flash file system can be used, but wear can still be an issue so it won’t work in all cases.