-
Notifications
You must be signed in to change notification settings - Fork 20
/
SDL_Pi_INA3221.py
165 lines (111 loc) · 6.13 KB
/
SDL_Pi_INA3221.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
#!/usr/bin/env python
# SDL_Pi_INA3221.py Python Driver Code
# SwitchDoc Labs March 4, 2015
# V 1.2
#encoding: utf-8
from datetime import datetime
import smbus
# constants
#/*=========================================================================
# I2C ADDRESS/BITS
# -----------------------------------------------------------------------*/
INA3221_ADDRESS = (0x40) # 1000000 (A0+A1=GND)
INA3221_READ = (0x01)
#/*=========================================================================*/
#/*=========================================================================
# CONFIG REGISTER (R/W)
# -----------------------------------------------------------------------*/
INA3221_REG_CONFIG = (0x00)
# /*---------------------------------------------------------------------*/
INA3221_CONFIG_RESET = (0x8000) # Reset Bit
INA3221_CONFIG_ENABLE_CHAN1 = (0x4000) # Enable Channel 1
INA3221_CONFIG_ENABLE_CHAN2 = (0x2000) # Enable Channel 2
INA3221_CONFIG_ENABLE_CHAN3 = (0x1000) # Enable Channel 3
INA3221_CONFIG_AVG2 = (0x0800) # AVG Samples Bit 2 - See table 3 spec
INA3221_CONFIG_AVG1 = (0x0400) # AVG Samples Bit 1 - See table 3 spec
INA3221_CONFIG_AVG0 = (0x0200) # AVG Samples Bit 0 - See table 3 spec
INA3221_CONFIG_VBUS_CT2 = (0x0100) # VBUS bit 2 Conversion time - See table 4 spec
INA3221_CONFIG_VBUS_CT1 = (0x0080) # VBUS bit 1 Conversion time - See table 4 spec
INA3221_CONFIG_VBUS_CT0 = (0x0040) # VBUS bit 0 Conversion time - See table 4 spec
INA3221_CONFIG_VSH_CT2 = (0x0020) # Vshunt bit 2 Conversion time - See table 5 spec
INA3221_CONFIG_VSH_CT1 = (0x0010) # Vshunt bit 1 Conversion time - See table 5 spec
INA3221_CONFIG_VSH_CT0 = (0x0008) # Vshunt bit 0 Conversion time - See table 5 spec
INA3221_CONFIG_MODE_2 = (0x0004) # Operating Mode bit 2 - See table 6 spec
INA3221_CONFIG_MODE_1 = (0x0002) # Operating Mode bit 1 - See table 6 spec
INA3221_CONFIG_MODE_0 = (0x0001) # Operating Mode bit 0 - See table 6 spec
#/*=========================================================================*/
#/*=========================================================================
# SHUNT VOLTAGE REGISTER (R)
# -----------------------------------------------------------------------*/
INA3221_REG_SHUNTVOLTAGE_1 = (0x01)
#/*=========================================================================*/
#/*=========================================================================
# BUS VOLTAGE REGISTER (R)
# -----------------------------------------------------------------------*/
INA3221_REG_BUSVOLTAGE_1 = (0x02)
#/*=========================================================================*/
SHUNT_RESISTOR_VALUE = (0.1) # default shunt resistor value of 0.1 Ohm
class SDL_Pi_INA3221():
###########################
# INA3221 Code
###########################
def __init__(self, twi=1, addr=INA3221_ADDRESS, shunt_resistor = SHUNT_RESISTOR_VALUE ):
self._bus = smbus.SMBus(twi)
self._addr = addr
config = INA3221_CONFIG_ENABLE_CHAN1 | \
INA3221_CONFIG_ENABLE_CHAN2 | \
INA3221_CONFIG_ENABLE_CHAN3 | \
INA3221_CONFIG_AVG1 | \
INA3221_CONFIG_VBUS_CT2 | \
INA3221_CONFIG_VSH_CT2 | \
INA3221_CONFIG_MODE_2 | \
INA3221_CONFIG_MODE_1 | \
INA3221_CONFIG_MODE_0
self._write_register_little_endian(INA3221_REG_CONFIG, config)
def _write(self, register, data):
#print "addr =0x%x register = 0x%x data = 0x%x " % (self._addr, register, data)
self._bus.write_byte_data(self._addr, register, data)
def _read(self, data):
returndata = self._bus.read_byte_data(self._addr, data)
#print "addr = 0x%x data = 0x%x %i returndata = 0x%x " % (self._addr, data, data, returndata)
return returndata
def _read_register_little_endian(self, register):
result = self._bus.read_word_data(self._addr,register) & 0xFFFF
lowbyte = (result & 0xFF00)>>8
highbyte = (result & 0x00FF) << 8
switchresult = lowbyte + highbyte
#print "Read 16 bit Word addr =0x%x register = 0x%x switchresult = 0x%x " % (self._addr, register, switchresult)
return switchresult
def _write_register_little_endian(self, register, data):
data = data & 0xFFFF
# reverse configure byte for little endian
lowbyte = data>>8
highbyte = (data & 0x00FF)<<8
switchdata = lowbyte + highbyte
self._bus.write_word_data(self._addr, register, switchdata)
#print "Write 16 bit Word addr =0x%x register = 0x%x data = 0x%x " % (self._addr, register, data)
def _getBusVoltage_raw(self, channel):
#Gets the raw bus voltage (16-bit signed integer, so +-32767)
value = self._read_register_little_endian(INA3221_REG_BUSVOLTAGE_1+(channel -1) *2)
if value > 32767:
value -= 65536
return value
def _getShuntVoltage_raw(self, channel):
#Gets the raw shunt voltage (16-bit signed integer, so +-32767)
value = self._read_register_little_endian(INA3221_REG_SHUNTVOLTAGE_1+(channel -1) *2)
if value > 32767:
value -= 65536
return value
# public functions
def getBusVoltage_V(self, channel):
# Gets the Bus voltage in volts
value = self._getBusVoltage_raw(channel)
return value * 0.001
def getShuntVoltage_mV(self, channel):
# Gets the shunt voltage in mV (so +-168.3mV)
value = self._getShuntVoltage_raw(channel)
return value * 0.005
def getCurrent_mA(self, channel):
#Gets the current value in mA, taking into account the config settings and current LSB
valueDec = self.getShuntVoltage_mV(channel)/ SHUNT_RESISTOR_VALUE
return valueDec;