树莓派4B的串口,由两个增加4个,一共6个!
情况一: 缺省镜像中的配置,测试发现只启用了2个:
pi@raspi4b:~ $ ls -l /dev/serial*
lrwxrwxrwx 1 root root 5 Jul 20 12:13 /dev/serial0 -> ttyS0
lrwxrwxrwx 1 root root 7 Jul 20 12:13 /dev/serial1 -> ttyAMA0
pi@raspi4b:~ $ ls -l /dev/tty*
crw-rw—- 1 root dialout 204, 64 Jul 20 12:13 /dev/ttyAMA0
crw——- 1 root root 5, 3 Jul 20 12:13 /dev/ttyprintk
crw–w—- 1 root tty 4, 64 Jul 20 12:13 /dev/ttyS0
pi@raspi4b:~ $ dtoverlay -h uart1
Name: uart1
Info: Change the pin usage of uart1
Usage: dtoverlay=uart1,=
Params: txd1_pin GPIO pin for TXD1 (14, 32 or 40 – default 14)
rxd1_pin GPIO pin for RXD1 (15, 33 or 41 - default 15)
情况二: 使用 raspi-config 工具,禁用 login shell, 禁用硬件serial, 重启后测试:
pi@raspi4b:~ $ ls -l /dev/tty*
crw-rw—- 1 root dialout 204, 64 Jul 20 12:22 /dev/ttyAMA0
crw——- 1 root root 5, 3 Jul 20 12:21 /dev/ttyprintk
pi@raspi4b:~ $ ll /dev/serial*
lrwxrwxrwx 1 root root 7 Jul 20 12:21 /dev/serial1 -> ttyAMA0
结论: login shell 串口使用的是: /dev/serial0 -> ttyS0
另外一个可能是蓝牙默认的: /dev/serial1 -> ttyAMA0
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zhw测试成功:使用uart2串口 自收自发
Name: uart2
Info: Enable uart 2 on GPIOs 0-3. BCM2711 only.
Usage: dtoverlay=uart2,
Params: ctsrts Enable CTS/RTS on GPIOs 2-3 (default off)
$ ls -l /dev/serial*
lrwxrwxrwx 1 root root 5 Jul 20 11:52 /dev/serial0 -> ttyS0
lrwxrwxrwx 1 root root 7 Jul 20 11:52 /dev/serial1 -> ttyAMA0
import serial
ted = serial.Serial(port=”/dev/ttyAMA1″, baudrate=9600)
ted.write(“Hello World”.encode(“gbk”))
11
ted.read(11)
b’Hello World’
以上 zhw 测试成功!
2022.7.20
Original: https://www.cnblogs.com/zhw618/p/16497568.html
Author: zhw618
Title: 树莓派4B串口测试与开发
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