Can I use the HAT eeprom pins as a uart?

Question

I have a Pi 4B and I want to use the HAT EEPROM I2C pins for the uart 4 that is behind them. This is a board just for me and all my other uart locations are in use. How do I disable the EEPROM scan and then configure those pins to be a uart?

Thank you.

Does this answer your question? How do I make serial work on the Raspberry Pi3 (PiZeroW, Pi4 or later models) https://raspberrypi.stackexchange.com/a/107780/8697 — Milliways, Nov 21 '22 at 21:09
@Milliways No, but maybe I'm doing something wrong ( I see I actually wanted uart2). So I added this enable_uart=2 force_eeprom_read=0 to my config.txt and rebooted. But no new device appeared like: /dev/AMA1 as described in that link. — confused, Nov 21 '22 at 21:19
I added dtoverlay=uart2 and a new /dev/ttyAMA1 appeared. Then I was able to write a byte out and see it on the scope. I don't know if enable_uart=2 is also needed. — confused, Nov 21 '22 at 21:36

score 1 · Accepted Answer · answered Nov 21 '22 at 21:30

1

I have used UART2 in the past. (I was actually trying to use the pins for other purposes - most failed) BUT I did get UART2 working and used it for serial communication as noted in a footnote to https://raspberrypi.stackexchange.com/a/107780/8697.

This was some time ago - probably running Buster. I can't confirm that it works with current OS but worth experimenting.

answered Nov 21 '22 at 21:30

Milliways

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Thank you for the suggestion! – confused Nov 22 '22 at 17:13

Can I use the HAT eeprom pins as a uart?

1 Answers1