Raspberry PI3、SerialPort和奇怪的响应

Question

我正在尝试使用串行端口（插孔）控制我的旧 Samsung DLP SP-A600B。为此，我重新使用了我的 Raspberry Pi 3，并插入了我在网上找到的 USB 转插孔电缆 (UART)。

我制作了一个小 Python 文件，但我不理解我收到的输出。这是我的代码：

import time
import serial

ser = serial.Serial(
    port='/dev/ttyUSB0',
    baudrate=9600,
    parity=serial.PARITY_NONE,
    stopbits=serial.STOPBITS_ONE,
    bytesize=serial.SEVENBITS
)

ON = b"\x08,\x22,\x00,\x00,\x00,\x00,\xD6"
# other hard-coded commands

ser.write(ON)
time.sleep(1)
out = ser.read(3)

# 0x03 0x0C 0x7F doesn't match the spec!

print out
ser.close()

根据to the manual：

5-2 RS-232C Command Table

Communication Format (Complies with the RS232C Standard)

Baud rate : 9,600 bps

parity : None

Data bits : 8, stop bit : 1

Flow Control : None

Serial Communication Protocol

Command Packet Structure [7bytes]

A command packet consists of 7 bytes in total.

The two bytes 0x08 and 0x22 signify that the packet is for serial communication.

The following 4 bytes represent a pre-defined command that can be defined by the user.

The last byte is the checksum which checks the validity of the current packet.

Header [2 Byte]: Pre-defined values fixed to 0x08 and 0x22.

Cmd1 [1 Byte]: The first value of the code defined in the command list (Hexadecimal)

Cmd2 [1 Byte]: The second value of the code defined in the command list (Hexadecimal)

Cmd3 [1 Byte]: The third value of the code defined in the command list (Hexadecimal)

Value [1 Byte]: Input parameter for the command (Default: 0) (Hexadecimal)

CS [1 Byte]: Checksum (the 2’s complement of the sum of all the values except for the CS value.)

Response Packet Structure [3 Bytes]

Success

0x03 0x0C 0xF1

Fail

0x03 0x0C 0xFF

我用这个 website 来计算第 7 个字节 (D6) 的 2 的补码（我更喜欢 NodeJS / Android）。不幸的是，我只收到

0x03 0x0C 0x7F

对于这个命令。如果我尝试设置奇怪的值，如 serial.PARITY_ODD 或 serial.EIGHTBITS，我会收到失败数据包

0x03 0x0C 0xFF

而且我没有成功收到一个成功包。任何帮助将不胜感激！

Answer 1

正如我们最终在评论中解决的那样，问题是命令字符串中有多余的逗号并且数据需要是 8 位的。

因此，具体来说，使用：

bytesize=serial.EIGHTBITS
...
...
ON = b"\x08\x22\x00\x00\x00\x00\xD6"

Raspberry PI3、SerialPort和奇怪的响应

Raspberry PI 3, SerialPort and strange response

python

bit-manipulation

pyserial

raspberry-pi

5-2 RS-232C Command Table

Communication Format (Complies with the RS232C Standard)

Serial Communication Protocol