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I am trying to use the second serial port. In /boot/config.txt I have put at the end :

# swap UARTs
dtoverlay=pi3-miniuart-bt
dtoverlay=uart2
enable_uart=1

I have checked and re-checked the pin connections. Uart 2 is on GPIO 0 and 3. Still cant receive anything from an arduino on the other side. Is there some configuration missing ?

dlsa
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3 Answers3

2

I use the following settings:

dtoverlay=uart2
dtoverlay=uart3

dtoverlay=pi3-miniuart-bt
enable_uart=1

They give access to uart2 (on GPIO 0 and 1) and uart3 (on GPIO 4 and 5). Bluetooth works, and the default UART on GPIO 14 and 15 is available as well.

PMF
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0

The BCM2711 has 6 UART (of which 4 are usable on the Pi4).

See How do I make serial work on the Raspberry Pi3 or later
Raspberry Pi4 UART

Milliways
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0

I was struggling with getting serial ports to work on Bookworm and my Pi4 for a few hours. I found a thread somewhere that someone said they used "sudo dtoverlay uart2" to get things to show up properly. Notice there is no "="? I changed my /boot/firmware/config.txt to this to get things working:

dtoverlay uart2
dtoverlay uart3
dtoverlay uart4

NO "="!
Maybe a bug?

Hope this helps someone that struggled like I did.

Aaron Weed
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