Serial Port
The Raspberry Pi GPIO expansion bus serial port is connected to Grove Connector
J8
.
The processor chip on the Raspberry Pi board has two different hardware serial
ports, either of which can be mapped to the GPIO expansion bus. The default
serial port device tree overlay command appended to
/boot/config.txt
is:
dtoverlay=disable-bt
This maps Linux serial port device
/dev/ttyAMA0
to Grove Connector
J8
.
Raspberry Pi 4 Extra Serial Port
Unlike any of its predecessors, the Raspberry Pi 4 has additional hardware serial
ports available on the GPIO expansion bus. One of these extra hardware serial
ports,
UART3
, can be mapped to Grove Connector
J5
by appending the following
device tree overlay command to
/boot/config.txt
:
dtoverlay=uart3
This maps Linux serial port device
/dev/ttyAMA1
to Grove Connector
J5
.
Note: All serial port connectors on this board provide 3.3V TTL line level signals.
They are
not
RS-232, RS-422, or RS-423 compatible.
MUNTS-0018 Raspberry Pi Tutorial I/O Board User Guide
Page 7 of 11
