craigsacco/raspberry_pi_projects

Random set of projects and drivers that interact with Raspberry Pi hardware using Python

raspberry_pi_projects's Issues

MAX127 driver test failure

Hi @craigsacco

I tried to test your MAX127 driver from my Raspberry connected with I2C protocol to my max127 DAS.

But it seems that there are some mistakes in the MAX127 class code, precisely in the function "get_data" :

def get_data(self):
value = 0
if self._bipolar:
value = (self._device.readRawS16BE() >> 4)
else:
value = (self._device.readRawU16BE() >> 4)
voltage = (value * MAX127.ADC_REFERENCE) /
(MAX127.ADC_MAX_VALUE >> (1 if self._bipolar else 0))
if self._range:
voltage = (voltage * 2.0)
return { "value": value, "voltage": voltage,
"channel": self._channel, "range": self._range,
"bipolar": self._bipolar }

Indeed, "readRawS16BE" and "readRawU16BE" functions imported from I2C.py ("Adafruit_GPIO" folder) don't exist. I believe you thought about using "readS16BE" and "readU16BE" functions still from I2C.py ?

Other question : were the max127 drivers tests successfull ? I didn't succeeded in getting value from a potentiometer (used to mesure a rotor position) with my MAX127 (voltage return by the function "get_data" of the MAX127 driver is always 5.0 volts even when I change the position of the rotor).

Last question : I think I'm wrong when precising "channel" value : I use int numbers (0 or 1) to cennect to channels 0 and 1 of the max127, is this correct ?

Thank you for your answers.

License

Hi @craigsacco,

I like your clean implementation of the Drivers and I would like to reuse some of them.

Would you mind licensing this under some permissive open source license?

Thanks!