from time import sleep
from pitop.common.bitwise_ops import split_into_bytes
from pitop.common.i2c_device import I2CDevice
[docs]class ADCProbe:
__device_address = 0x2A
__register_address = 0
__channel_count = 6
__adc_ratio = 20
def __init__(self, i2c_device_name="/dev/i2c-1"):
self.__i2c_device_name = i2c_device_name
self.__device = None
self.__error_array = [-1] * self.__channel_count
[docs] def read_value(self, channel):
if (channel < 0) or (channel > self.__channel_count):
print("Invalid channel - use 0 to " + str(self.__channel_count - 1))
return -1
results = self.read_all()
return results[channel]
[docs] def read_all(self):
if self.__connect() is False:
print("Could not connect to device")
return self.__error_array
results_reading = self.__device.read_n_unsigned_bytes(
self.__register_address, number_of_bytes=self.__channel_count
)
results = split_into_bytes(
results_reading, self.__channel_count, little_endian=False
)
data_read_len = len(results)
self.__disconnect()
if data_read_len != self.__channel_count:
print(
"Bad read from device. "
f"Expected {str(self.__channel_count)} bytes, received {str(data_read_len)} bytes."
)
return self.__error_array
for i in range(self.__channel_count):
results[i] *= self.__adc_ratio
results[i] = int(results[i])
return results
[docs] def poll(self, delay=0.5):
print("| ADC0\t| ADC1\t| ADC2\t| ADC3\t| ADC4\t| ADC5\t|")
print("-------------------------------------------------")
while True:
results = self.read_all()
print(
"| "
+ str(results[0])
+ "\t| "
+ str(results[1])
+ "\t| "
+ str(results[2])
+ "\t| "
+ str(results[3])
+ "\t| "
+ str(results[4])
+ "\t| "
+ str(results[5])
+ "\t|"
)
sleep(delay)
def __connect(self):
try:
self.__device = I2CDevice(self.__i2c_device_name, self.__device_address)
self.__device.connect()
except Exception as e:
print("Unable to read from ADC over I2C: " + str(e))
return False
return True
def __disconnect(self):
if self.__device is not None:
self.__device.disconnect()