Geekworm UPS3 RPi HAT Modified Example Code

smartups3.py

import os, smbus, time, logging, atexit
from datetime import datetime

log_file = '/home/rover_logs/rover-battery-log-' + datetime.now().strftime('%m-%d-%y') + '.txt'
logging.basicConfig(filename=log_file,level=logging.DEBUG)
logging.info('==================== Rover UPS3 Battery Capacity Communications Client Logging Started ' + datetime.now().strftime('%m-%d-%y %H:%M:%S'))

BYTE_CONV_ADC_START = 0b10011101
BYTE_CONV_ADC_STOP  = 0b00011101
BYTE_WATCHDOG_STOP  = 0b10001101 #Stop Watchdog timer
MAX17048_ADDR 	= 0x36
BQ25895_ADDRESS = 0x6A
REG_WATCHDOG    = 0x07
REG_ILIM 		= 0x00 #ILIM register
BYTE_ILIM 		= 0b01111111 #3.25A input current limit
REG_ICHG 		= 0x04 
BYTE_ICHG 		= 0b01111111 #.5A charging current limit
REG_BATFET 		= 0x09
BYTE_BATFET 	= 0b01001000 #delay before battery == disconnected
REG_CONV_ADC 	= 0x02
REG_STATUS		= 0x0B #address of status register
REG_BATV		= 0x0e
BAT_CAPACITY 	= 2500 #Battery capacity in mah
CURRENT_DRAW 	= 2000 #Current draw in mah
disconnectflag 	= False
POWEROFF_POWER  = 5
count = 0

def shutdown(*kwarg):
    logging.info('Shutdown occurred, shutting RPi down now at ' + str(datetime.now().strftime('%H:%M:%S')) + '.')
atexit.register(shutdown)

def bq25895_int_to_bool_list(num):
	return [bool(num & (1<<n)) for n in range(8)]

def bq25895_translate(val, in_from, in_to, out_from, out_to):
	out_range = out_to - out_from
	in_range = in_to - in_from
	in_val = val - in_from
	val=(float(in_val)/in_range)*out_range
	out_val = out_from+val
	return out_val

# Get voltage from max17048
def max17048_getstatus():
	global max17048_v, max17048_soc
	max17048_v_16 = bus.read_word_data(MAX17048_ADDR, 0x02);
	soc = bus.read_word_data(MAX17048_ADDR, 0x04);
	max17048_v = (((max17048_v_16 & 0x00FF) << 8) + (max17048_v_16 >> 8)) * 78.125 / 1000000
	max17048_soc = (((soc & 0x00FF) << 8) + (soc >> 8)) / 256

bus = smbus.SMBus(1)
bus.write_word_data(MAX17048_ADDR, 0xFE ,0xFFFF)
bus.write_byte_data(BQ25895_ADDRESS, REG_WATCHDOG, BYTE_WATCHDOG_STOP)
bus.write_byte_data(BQ25895_ADDRESS, REG_ILIM, BYTE_ILIM)
bus.write_byte_data(BQ25895_ADDRESS, REG_ICHG, BYTE_ICHG)
bus.write_byte_data(BQ25895_ADDRESS, REG_BATFET, BYTE_BATFET)

# BQ25895 read status
def bq25895_read_status():
	global  disconnectflag, bq25895_status
	bus.write_byte_data(BQ25895_ADDRESS, REG_CONV_ADC, BYTE_CONV_ADC_START)
	sample = bus.read_byte_data(BQ25895_ADDRESS, REG_STATUS)
	status = bq25895_int_to_bool_list(sample)
	time.sleep(1.2)
	sample = bus.read_byte_data(BQ25895_ADDRESS, REG_BATV)
	batvbool = bq25895_int_to_bool_list(sample)
	bus.write_byte_data(BQ25895_ADDRESS, REG_CONV_ADC, BYTE_CONV_ADC_STOP)
	
	vsys_stat = status[0]
	sdp_stat = status[1]
	pg_stat = status[2]
	chrg_stat = status[4] * 2 + status[3]
	vbus_stat = status[7] * 4 + status[6] * 2 + status[5]
	
	if status[2]:
		power = "Connected"
	else:
		power = "Disconnected"

	if status[3] and status[4]:
		charge = "Charging done"
	elif status[4] and  not status[3]:
		charge = "Charging"
	elif not status[4] and status[3]:
		charge = "Pre-Charge"
	else:
		charge = "Discharging"
		
	#convert batv register to volts
	batv = 2.304
	batv += batvbool[6] * 1.280
	batv += batvbool[5] * 0.640
	batv += batvbool[4] * 0.320
	batv += batvbool[3] * 0.160
	batv += batvbool[2] * 0.08
	batv += batvbool[1] * 0.04
	batv += batvbool[0] * 0.02   

	batpercent = bq25895_translate(batv,3.5,4.184,0,1)
	if batpercent<0 :
		batpercent = 0
	elif batpercent >1 :
		batpercent = 1

	timeleftmin = int( batpercent * 60* BAT_CAPACITY / CURRENT_DRAW)
	if timeleftmin < 0 :
		timeleftmin = 0

	if power == "Connected" :
		timeleftmin = -1        

	if power == "Disconnected" and disconnectflag == False :
		disconnectflag = True
		message = "***** Battery at " + str(int(batpercent * 100)) + "%. Power Disconnected, system will shutdown in " + str((timeleftmin)) + " minutes!" 
		print(message)
		logging.info(message)

	if power == "Connected" and disconnectflag == True :
		disconnectflag = False
		message = "***** Power Restored, battery at " + str(int(batpercent * 100)) + "%." 
		print(message)
		logging.info(message)

	bq25895_status = { 
		'Input': power,
		'ChargeStatus' : charge,
		'BatteryVoltage' : '%.2f' % batv,
		"BatteryPercentage" : int(batpercent*100),
		'TimeRemaining' : int(timeleftmin)
		}
	if(batv < 3.5):
		bus.write_byte_data(BQ25895_ADDRESS, REG_BATFET_DIS, BYTE_BATFET_DIS)
	
max17048_getstatus()
bq25895_read_status()

print ("Input: " , bq25895_status['Input'])
print ("State: " , bq25895_status['ChargeStatus'])
print ("Voltage: " , bq25895_status['BatteryVoltage'])
print ("Capacity: " + str(bq25895_status['BatteryPercentage']) + "%")
print ("max17048_soc: " + str(max17048_soc))

try:
	while (True):
		max17048_getstatus()
		bq25895_read_status()
		if ((bq25895_status['Input'] != 'Connected') and (max17048_soc < POWEROFF_POWER)):
			count += 1
			message = "**** Shutting down in " + str(50-(count*5)) + " seconds. Value max17048_soc = " + str(max17048_soc) + " *****"
			print(message)
			logging.info(message)
			if count == 10:
				os.system("sudo halt -h")
		if str(bq25895_status['Input']) == 'Connected':
			message = str(datetime.now().strftime('%H:%M:%S')) + " - Input: " + str(bq25895_status['Input']) + ", State: " + str(bq25895_status['ChargeStatus']) + ", Voltage: " + str(bq25895_status['BatteryVoltage']) + ", Capacity: " + str(bq25895_status['BatteryPercentage']) + "%. Value max17048_soc = " + str(max17048_soc)
		else:
			message = str(datetime.now().strftime('%H:%M:%S')) + " - Input: " + str(bq25895_status['Input']) + ", State: " + str(bq25895_status['ChargeStatus']) + ", Voltage: " + str(bq25895_status['BatteryVoltage']) + ", max17048_soc: " + str(max17048_soc) + ", TimeRemaining: " + str(bq25895_status['TimeRemaining']) + " minutes."
		print (message)
		logging.info(message)
		time.sleep(5)
except Exception as err:
	message = 'Exception error: ' + str(err)
	print (message)
	logging.info(message)
	exit