Does anyone know how many UARTS will the new mesh products have?


Just wondering if anyone knows how many UARTS besides the USB will the new MESH products will have ?

Seems like only one will be exposed thru the chip pins?


I don’t have the answer, however the nRF52840 has two hardware UARTs.

It’s quite possible that only one will be accessible, however, due to the limited number of pins that can be exposed through the Feather pinout.


Thank you.

I have an application where I will need 3 serial ports, at 19200 bps.

Do you think a 2 software serials would be possible with this mcu?


The clock speed on the nRF52840 is slower, so that might be an issue, but I don’t know how fast the interrupt serving is, that will be the main bottleneck. If you handle each port sequentially, for example send and receive data, then move to the next one you should be fine.

If you need to continuously receive from all ports at once at 19200, that will be more of a problem. I’d use the SC16IS740. It’s an I2C UART. You can connect 4 of them to a single I2C port (pins D0 and D1 on the current devices) and works up to 115200 baud. Each has two 64-byte FIFO to hold the data for sending or receiving.

That link is to the Particle library for it. It should work on the mesh devices as it just uses the standard Wire interface.


This is an awesome project. Thank you for sharing @rickkas7

If you make some breakouts assembled I am a potential customer for 5 or 10 of them :slight_smile:

BY THE WAY: Do you know of a chip with more than one UART?


Thanks! The SC16IS752 has two UARTs per chip, and you connect 4 of them to the I2C bus so you can have 8 UARTs going that way. My SC16IS740 driver doesn’t currently support it, but it’s a minor change. I may build a board so I can test it.

I don’t currently have plans to manufacture the breakout board because it’s tedious making them by hand, but I’ll look into having them built and see if it’s practical.


Outstanding. Il be a customer for sure.

Do you have a preference where you send to build your own boards? (Don’t mean making the PCBs) but assembling and putting them together. I also hate SMDs by hand and wish I can send to third party for low volume production or prototyping (say 10-15 boards >).



The answer to the original question is:

There is a serial port on the RX and TX pins, and it supports optional hardware flow control (CTS/RTS on D3 and D2).

Serial Alt nRF52840
TX D9 P0.06
RX D10 P0.08
CTS D3 P1.02
RTS D2 P1.01

The nRF52840 has two hardware UARTs, and the optional second UART should be available on these pins. This could change.

Serial Alt nRF52840
TX1 D4 P1.08
RX1 D5 P1.10
CTS1 D6 P1.11
RTS1 D8 P1.03


Thanks so much.

Would be a matter of seeing if they will expose those pins some how in the Mesh products.