feature/unit/vmeter: 16-bit ADS1115 analog-to-digital converter

Author: pandiannano

m5stack/libs/unit/vmeter.py

@@ -0,0 +1,218 @@
+from machine import I2C
+from .pahub import PAHUBUnit
+from .unit_helper import UnitError
+import struct
+import sys
+
+if sys.platform != "esp32":
+    from typing import Union
+
+import time
+import struct
+
+ADS1115_ADDR = 0x49
+EEPROM_ADDR = 0x53
+
+RA_CONVERSION = 0x00
+RA_CONFIG = 0x01
+
+MODE_CONTINUOUS = 0x00
+MODE_SINGLESHOT = 0x01
+
+PGA_6144 = 0x00
+PGA_4096 = 0x01
+PGA_2048 = 0x02
+PGA_1024 = 0x03
+PGA_512 = 0x04
+PGA_256 = 0x05
+
+RATE_8 = 0x00
+RATE_16 = 0x01
+RATE_32 = 0x02
+RATE_64 = 0x03
+RATE_128 = 0x04
+RATE_250 = 0x05
+RATE_475 = 0x06
+RATE_860 = 0x07
+
+MV_6144 = 0.187500
+MV_4096 = 0.125000
+MV_2048 = 0.062500
+MV_1024 = 0.031250
+MV_512 = 0.015625
+MV_256 = 0.007813
+
+MEASURING_DIR = -1
+
+VOLTAGE_DIVIDER_COEFFICIENT = 0.015918958
+
+PAG_6144_CAL_ADDR = 208
+PAG_4096_CAL_ADDR = 216
+PAG_2048_CAL_ADDR = 224
+PAG_1024_CAL_ADDR = 232
+PAG_512_CAL_ADDR = 240
+PAG_256_CAL_ADDR = 248
+
+Resolution_list = {0: MV_6144 / VOLTAGE_DIVIDER_COEFFICIENT,
+                   1: MV_4096 / VOLTAGE_DIVIDER_COEFFICIENT,
+                   2: MV_2048 / VOLTAGE_DIVIDER_COEFFICIENT,
+                   3: MV_1024 / VOLTAGE_DIVIDER_COEFFICIENT,
+                   4: MV_512 / VOLTAGE_DIVIDER_COEFFICIENT,
+                   5: MV_256 / VOLTAGE_DIVIDER_COEFFICIENT}
+
+PGA_EEPROM_Addr_list = {0: PAG_6144_CAL_ADDR,
+                        1: PAG_4096_CAL_ADDR,
+                        2: PAG_2048_CAL_ADDR,
+                        3: PAG_1024_CAL_ADDR,
+                        4: PAG_512_CAL_ADDR,
+                        5: PAG_256_CAL_ADDR}
+
+Rate_list = {0: 1000 / 8,
+             1: 1000 / 16,
+             2: 1000 / 32,
+             3: 1000 / 64,
+             4: 1000 / 128,
+             5: 1000 / 250,
+             6: 1000 / 475,
+             7: 1000 / 860}
+
+class VMeterUnit:
+
+    def __init__(self, i2c: Union[I2C, PAHUBUnit], ads_addr=ADS1115_ADDR):
+        self.ads_i2c = i2c
+        self.ads_i2c_addr = ads_addr
+        if not (self.ads_i2c_addr in self.ads_i2c.scan()):
+            raise UnitError("Vmeter unit maybe not connect")
+        self.eeprom_i2c = i2c
+        self.eeprom_i2c_addr = EEPROM_ADDR
+        self._gain = PGA_2048
+        self._rate = RATE_128
+        self._mode = MODE_SINGLESHOT
+        self._calibration_factor = 1
+        self._resolution = Resolution_list[self._gain]
+        self._cover_time = Rate_list[self._rate]
+        self.calibration = True
+
+    def set_gain(self, gain):
+        buf = self.ads_i2c.readfrom_mem(self.ads_i2c_addr, RA_CONFIG, 2)
+        config = struct.unpack('>h', buf)[0]
+        config &= ~(0b0111 << 9)
+        config |= gain << 9
+        buf = struct.pack('>h', config)
+        self.ads_i2c.writeto_mem(self.ads_i2c_addr, RA_CONFIG, buf)
+        self._gain = gain
+        self._resolution = Resolution_list[self._gain]
+        expect, real = self.read_calibration(self._gain)
+        self._calibration_factor = expect / real
+    
+    def get_gain(self):
+        buf = self.ads_i2c.readfrom_mem(self.ads_i2c_addr, RA_CONFIG, 2)
+        config = struct.unpack('>h', buf)[0]
+        return ((config & (0b0111 << 9)) >> 9)
+
+    def set_data_rate(self, rate):
+        buf = self.ads_i2c.readfrom_mem(self.ads_i2c_addr, RA_CONFIG, 2)
+        config = struct.unpack('>h', buf)[0]
+        config &= ~(0b0111 << 5)
+        config |= rate << 5
+        buf = struct.pack('>h', config)
+        self.ads_i2c.writeto_mem(self.ads_i2c_addr, RA_CONFIG, buf)
+        self._rate = rate
+        self._cover_time = Rate_list[self._rate]
+    
+    def get_data_rate(self):
+        buf = self.ads_i2c.readfrom_mem(self.ads_i2c_addr, RA_CONFIG, 2)
+        config = struct.unpack('>h', buf)[0]
+        return ((config & (0b0111 << 5)) >> 5)
+
+    def set_operation_mode(self, mode):
+        buf = self.ads_i2c.readfrom_mem(self.ads_i2c_addr, RA_CONFIG, 2)
+        config = struct.unpack('>h', buf)[0]
+        config &= ~(0b0001 << 8)
+        config |= mode << 8
+        buf = struct.pack('>h', config)
+        self.ads_i2c.writeto_mem(self.ads_i2c_addr, RA_CONFIG, buf)
+        self._mode = mode
+    
+    def get_operation_mode(self):
+        buf = self.ads_i2c.readfrom_mem(self.ads_i2c_addr, RA_CONFIG, 2)
+        config = struct.unpack('>h', buf)[0]
+        return ((config & (0b0001 << 8)) >> 8)
+
+    def get_voltage(self):
+        if self.calibration:
+            return self._resolution * self._calibration_factor * self.conversion() * MEASURING_DIR
+        else:
+            return self._resolution * self.conversion() * MEASURING_DIR
+    
+    def get_adc_raw(self):
+        return self.conversion()
+
+    def conversion(self, timeout=125):
+        if self._mode == MODE_SINGLESHOT:
+            self.single_conversion()
+            time.sleep_ms(int(self._cover_time))
+            time_ms = time.ticks_ms() + timeout
+            while (time.ticks_ms() < time_ms and self.is_conversion()):
+                pass
+
+        return self.adc_raw()
+
+    def single_conversion(self):
+        buf = self.ads_i2c.readfrom_mem(self.ads_i2c_addr, RA_CONFIG, 2)
+        config = struct.unpack('>h', buf)[0]
+        config &= ~(0b0001 << 15)
+        config |= 0x01 << 15
+        buf = struct.pack('>h', config)
+        self.ads_i2c.writeto_mem(self.ads_i2c_addr, RA_CONFIG, buf)
+
+    def is_conversion(self):
+        buf = self.ads_i2c.readfrom_mem(self.ads_i2c_addr, RA_CONFIG, 2)
+        result = struct.unpack('>h', buf)[0]
+        if result & (1 << 15):
+            return False
+        else:
+            return True
+
+    def adc_raw(self):
+        buf = self.ads_i2c.readfrom_mem(self.ads_i2c_addr, RA_CONVERSION, 2)
+        return struct.unpack('>h', buf)[0]
+
+    def eeprom_read(self, reg, num):
+        return self.eeprom_i2c.readfrom_mem(self.eeprom_i2c_addr, reg, num)
+
+    def eeprom_write(self, reg, data):
+        buf = bytearray(data)
+        self.eeprom_i2c.writeto_mem(self.eeprom_i2c_addr, reg, buf)
+
+    def save_calibration(self, gain, expect, real):
+        if expect == 0 and real == 0:
+            return
+        buf = [0] * 8
+        buf[0] = gain
+        buf[1] = expect >> 8
+        buf[2] = expect & 0xff
+        buf[3] = real >> 8
+        buf[4] = real & 0xff
+
+        for i in range(0, 5):
+            buf[5] ^= buf[i]
+
+        addr = PGA_EEPROM_Addr_list[gain]
+        self.eeprom_write(addr, buf)
+
+    def read_calibration(self, gain):
+        expect = 1
+        real = 1
+        addr = PGA_EEPROM_Addr_list[gain]
+        read_data = self.eeprom_read(addr, 8)
+        crc = 0
+        for i in range(0, 5):
+            crc ^= read_data[i]
+
+        if crc != read_data[5]:
+            return expect, real
+
+        expect = read_data[1] << 8 | read_data[2]
+        real = read_data[3] << 8 | read_data[4]
+        return expect, real