Questions about the upcoming Photon 2

Hi - I just received the email about the new Supply Secure Hardware portfolio. I have some questions on the Photon 2:

  1. Will this also support 7 data bits (like the Photon), or only 8 like the Argon?
  2. Can a customer use the Particle iOS app + skip authentication and/or use SoftAP to (re-)provision WiFi (like the Photon), or is this not possible (like the Argon)?

I am sincerely hoping the Photon 2 is actually a Photon 2, and not an Argon 2. Thank you.

7-bit UART serial is supported.

Photon Photon 2
Buffer size 64 bytes 2048 bytes
7-bit mode
8-bit mode
9-bit mode
1 stop bit
2 stop bits
No parity
Even parity
Odd parity
Break detection
LIN bus support
Half duplex
CTS/RTS flow control ✓1

The P2 and Photon 2 are configured by BLE like the Argon and will not support Soft AP. They cannot be configured using the Photon Device Setup SDK for iOS or Android.

However, sample code will be provided to use React Native to configure Wi-Fi on a P2 or Photon 2 from your own custom mobile app.

There are many more answers in the Photon 2 from Photon Migration Guide.

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Thanks for the help as always @rickkas7.

Photon 2? wow, that’s quite some news!!!

Wow again! GEN4?
Looks like some Spectra news is leaking out. Can’t wait for May.

this one is apparently GEN3:

Regardless, exiting news!

@rickkas7 may we check out a prelim. picture of a Photon 2 by any chance?
I see there are diagrams on the docs, but could not find a pic. Thanks!

Correct, not actually Gen 4. Maybe Gen 3.5.

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.


Something seems slightly confusing in the migration docs.
The features list states a single UART

But then further down Serial2 is mentioned for the P2

Is this a single UART that can have alternate pins asignemnts (like Wire & Wire1 on the Electron) or are there actually 2 UARTs and the feature list is wrong?

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.

I read here the Photon is going away because Cypress is discontinuing the P1 module.
What happened with the Argon? Is Nordic up to something as well?

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 P2/Photon 2 support Ethernet.


Are you planning rewrite the network stack from the Argon? Will use of Ethernet or WiFi need to be made at setup or could both co-exist and there be an automatic switch to ethernet if connected?

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.

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One last question - why was the retained memory (SRAM) feature dropped? Could you think of a workaround for maintaining a high frequency update state array that can be recovered after a restart?

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.

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