Raspberry Pi MAX31865 Python到Java的转换

我正在尝试将一段读取MAX13865传感器的Python代码转换为Java。Python代码运行良好并返回预期的数字（1238），而Java版本总是返回32767。为了简化阅读，我将Python代码和Java代码缩减到最小。下面的Python代码仍然运行良好。我错过了什么？这似乎很简单，但仍然不起作用

#!/usr/bin/python -tt

import RPi.GPIO as GPIO
import time
import datetime
import math

class MAX31865(object):

    def __init__(self, cs_pin, clock_pin, data_in_pin, data_out_pin, board = GPIO.BCM):

        self.cs_pin = cs_pin
        self.clock_pin = clock_pin
        self.data_in_pin = data_in_pin
        self.data_out_pin = data_out_pin
        self.board = board

        # Initialize needed GPIO
        GPIO.setmode(self.board)
        GPIO.setup(self.cs_pin, GPIO.OUT)
        GPIO.setup(self.clock_pin, GPIO.OUT)
        GPIO.setup(self.data_in_pin, GPIO.IN)
        GPIO.setup(self.data_out_pin, GPIO.OUT)

        # Pull chip select high to make chip inactive
        GPIO.output(self.cs_pin, GPIO.HIGH)

    def get_data(self):
        '''Acqures raw RDT data.'''
        self.address = int(0x01)    #RTD MSBs
        MSB = self.read()
        self.address = int(0x02)    #RTD LSBs
        LSB = self.read()
        MSB = MSB<<8
        raw = MSB+LSB
        raw = raw>>1
        return raw

    def read(self):
        '''Reads 16 bits of the SPI bus from a self.address register & stores as an integer in self.data.'''
        bytesin = 0

        # Select the chip
        GPIO.output(self.cs_pin, GPIO.LOW)
        # Assert clock bit
        GPIO.output(self.clock_pin, GPIO.LOW)

        # Write to address
        for i in range(8):
            bit  = self.address>>(7 - i)
            bit = bit & 1
            GPIO.output(self.data_out_pin, bit)
            GPIO.output(self.clock_pin, GPIO.HIGH)
            GPIO.output(self.clock_pin, GPIO.LOW)

        # Read in 8 bits
        for i in range(8):
            GPIO.output(self.clock_pin, GPIO.HIGH)
            bytesin = bytesin << 1
            if (GPIO.input(self.data_in_pin)):
                bytesin = bytesin | 1
            GPIO.output(self.clock_pin, GPIO.LOW)
        # Dsable clock
        GPIO.output(self.clock_pin, GPIO.HIGH)
        # Unselect the chip
        GPIO.output(self.cs_pin, GPIO.HIGH)

        # Save data
        self.data = bytesin
        return self.data

if __name__ == "__main__":
    cs_pin = 8
    clock_pin = 11
    data_in_pin = 9
    data_out_pin = 10

    # Configure RTDs
    rtd = MAX31865(cs_pin, clock_pin, data_in_pin, data_out_pin)
    log_string = ''

    # Run main loop
    running = True
    while(running):
        try:
            RTD_code = rtd.get_data()
            print '{:.0f}'.format(RTD_code * 4300 / 32768)
            time.sleep(0.1)
        except KeyboardInterrupt:
            running = False
    GPIO.cleanup()

---

这个问题与Pi4J将GPIO引脚号映射到Python版本的方式有关

Python版本：

MAX31865(8, 11, 9, 10)

和java等价物：

MAX31865 max = new MAX31865(RaspiPin.GPIO_10, RaspiPin.GPIO_14, RaspiPin.GPIO_13, RaspiPin.GPIO_12);

请注意，pin码是不同的。但现在两者给出了完全相同的结果。其他一切都很好

---

RTFM:（

请检查

get_data

中读取的值（

msb

，

lsb

，

msb

，

lsb

）在java版本中，msb和lsb的值都是255。在Python版本中，我得到75和69（结果是1264，即68.22C）嗯，好的。那么，当你在写地址时，请检查每次迭代中的

bit

，当你进行位移位时，请检查

bytesin

。地址正确吗？在Python中：[code]0 0 0 0 0 0 0 1 0 0 0 2 6 30 60 0 0 0 0 0 0 0 1 0 0 2 6 28 56[code]在Java中：[code]0 0 0 0 0 0 1 0 0 0 2 6 14 30 60 0 0 0 0 0 0 0 0 1 0 0 2 6 14 28 56[代码]地址似乎很好，但读取结果似乎错误…当我打印GPIO.input（自我数据输入）时我明白了：0 0 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

MAX31865(8, 11, 9, 10)

MAX31865 max = new MAX31865(RaspiPin.GPIO_10, RaspiPin.GPIO_14, RaspiPin.GPIO_13, RaspiPin.GPIO_12);