Reading TI TMP100 sensor via i2c and libmpsse

tmp100_i2c_read.py

# -*- coding: utf-8 -*- 
from mpsse import *
import time

i2c = MPSSE(I2C, FOUR_HUNDRED_KHZ)
#i2c = MPSSE(I2C, ONE_HUNDRED_KHZ)

# Adress: \x4A (base) -> write: \x94 , read: \x95
# Configuration: \x60 (01100000b : 12bit resolution)

WCMD = '\x94'
RCMD = '\x95'
CADR = '\x01'
DADR = '\x00'
CONF = '\x60'

def init():
  i2c.Start()                         # send i2c start condition
  i2c.Write(WCMD)                     # send slave addr with write bit
  i2c.Write(CADR)                     # set register pointer to config register
  if i2c.GetAck() == ACK:             # get ACK from slave
    i2c.Write(CONF)                   # set configuration value
    if i2c.GetAck() == ACK:           # get ACK from slave
      print 'Init done'
      i2c.Start()                     # send new i2c start condition
      i2c.Write(WCMD+DADR)            # send addr with write bit and set pointer reg
      if not i2c.GetAck() == ACK:
        print '#no ack: set data reg'
        return False
    else:
      print '#no ack: set config'
      return False
  else:
    print '#no ack: set pointer reg'
    return False
  i2c.Stop()
  return True


def getData():
  data = None
  i2c.Start()                         # send i2c start condition
  i2c.Write(RCMD)                     # send slave addr with read bit
  if i2c.GetAck() == ACK:
    #print 'reading data'
    data = i2c.Read(2)                # reading 2 bytes with ack
  i2c.Stop()
  #return list(data)
  return [ord(data[0]),ord(data[1])*1000/256]



if init() == True:
  try:
    while True:
      val = getData()
      print val
      time.sleep(.400)
  except KeyboardInterrupt:
    pass

i2c.Close()