我正在使用Adafruit的Circuit Playground Express,我正在使用Circuit Python进行编程。
我想读取从Circuit Playground Express通过USB连接的计算机传输的数据。使用input()
工作正常,但我宁愿得到串口的缓冲区,这样循环就会继续,而没有输入。像serial.read()
这样的东西。
import serial
不适用于Circuit Python,或者我必须安装一些东西。我还能做些什么来使用Circuit Python读取串行缓冲区吗?
答案 0 :(得分:2)
This is now somewhat possible!
In the January stable release of CircuitPython 3.1.2 the function serial_bytes_available
was added to the supervisor
module.
This allows you to poll the availability of serial bytes.
For example in the CircuitPython firmware (i.e. boot.py
) a serial echo example would be:
import supervisor
def serial_read():
if supervisor.runtime.serial_bytes_available():
value = input()
print(value)
and ensure when you create the serial device object on the host side you set the timeout wait to be very small (i.e. 0.01).
i.e in python:
import serial
ser = serial.Serial(
'/dev/ttyACM0',
baudrate=115200,
timeout=0.01)
ser.write(b'HELLO from CircuitPython\n')
x = ser.readlines()
print("received: {}".format(x))
答案 1 :(得分:1)
显然,截至目前,这是不可能的。请参阅Adafruit here的完整讨论。
答案 2 :(得分:0)
艾登的答案引导我朝着正确的方向发展,我在这里找到了一个很好的(略有不同)如何使用Adafruit的supervisor.runtime.serial_bytes_available
的示例(具体来说是89-95行):https://learn.adafruit.com/AT-Hand-Raiser/circuitpython-code
code.py
的一个最小工作示例是输入,并以“ RX:string”格式设置新字符串的格式是
import supervisor
print("listening...")
while True:
if supervisor.runtime.serial_bytes_available:
value = input().strip()
# Sometimes Windows sends an extra (or missing) newline - ignore them
if value == "":
continue
print("RX: {}".format(value))
测试于:Adafruit CircuitPython 4.1.0 on 2019-08-02;带有samd21g18的Adafruit ItsyBitsy M0 Express。在macOS上通过mu-editor中的串行连接发送的消息。
样本输出
main.py output:
listening...
hello!
RX: hello!
答案 3 :(得分:0)
基于上述帖子,我有一个简单的示例可以工作,不确定它是否稳定或有用,但仍在此处发布:
CircuitPython代码:
import supervisor
while True:
if supervisor.runtime.serial_bytes_available:
value = input().strip()
print(f"Received: {value}\r")
PC代码
import time
import serial
ser = serial.Serial('COM6', 115200) # open serial port
command = b'hello\n\r'
print(f"Sending Command: [{command}]")
ser.write(command) # write a string
ended = False
reply = b''
for _ in range(len(command)):
a = ser.read() # Read the loopback chars and ignore
while True:
a = ser.read()
if a== b'\r':
break
else:
reply += a
time.sleep(0.01)
print(f"Reply was: [{reply}]")
ser.close()
c:\circuitpythontest>python TEST1.PY
Sending Command: [b'hello\n\r']
Reply was: [b'Received: hello']