finally this work for me :) thanks for your time Graham
*working python script* import smbus import time # General i2c device class so that other devices can be added easily class i2c_device: def __init__(self, addr, port): self.addr = addr self.bus = smbus.SMBus(port) def write_i2c_block_data(self, byte, array): self.bus.write_i2c_block_data(self.addr, byte, array) def read_nbytes_data(self, data, n): # For sequential reads > 1 byte return self.bus.read_i2c_block_data(self.addr, data, n) ph = i2c_device(0x65, 2) print(ph.read_nbytes_data(0x00, 25)) //read all registers ph.write_i2c_block_data(0x05,[0x00]) // off LED On Friday, June 16, 2017 at 5:02:59 PM UTC-4, Graham wrote: > > Sebastián: > > Is your Arduino 3.3V or 5.0 V I/O? > > What clock speed are you running the I2C bus in the Beaglebone? > With the time distortion in the level translator, I would not go above 100 > kHz until proven good at higher speeds. > > I note that your schematic shows VDDP connected to 5V. > This should be connected to the same reference Voltage as the I2C bus is > using, which is 3.3V in the case of the Beaglebone. > > I have not digested the ADM3260 data sheet sufficiently to understand if > it is OK to run both buses at 3.3V, and the power supply input at 5V. > Is this what you are actually doing when on the Beaglebone? > > --- Graham > > == > > On Fri, Jun 16, 2017 at 12:34 PM, Sebastián Sáez <[email protected] > <javascript:>> wrote: > >> This are the value in hexadecimal of the 25 registers in the sensor, >> check with datasheet and it's ok >> >> 1,4,1,65,0,1,0,1,0,0,0,0,0,0,0,0,9,C4,0,0,9,C4,0,0,16 >> >> >> I used arduino to read this, I discovered that what I read with python is >> garbage >> >> On Friday, June 16, 2017 at 12:43:14 PM UTC-4, Sebastián Sáez wrote: >>> >>> Hi Graham, thanks >>> >>> here more info >>> >>> HW: Beaglebone seeedstudio green wireless >>>> OS: Debian GNU/Linux 8.8 (jessie) >>>> Kernel: Linux beaglebone 4.4.30-ti-r64 >>>> Python: Python 2.7.9 >>> >>> >>> I made a custom cape, the sensor it's power with 3.3v and conected to >>> I2C_2 through an isolator >>> >>> SDA -> P9.20 >>> SCL -> P9.19 >>> >>> >>> <https://lh3.googleusercontent.com/-LQRB-CkLTZo/WUQGKC1Q1bI/AAAAAAAADKA/bTmen-ZCt0gd_AsHUnmU78UUmiNiZ3-9wCLcBGAs/s1600/Untitled.png> >>> >>> The HW it's OK, I check with an arduino and example code and I can write >>> registers with my python script on the beaglebone. >>> >>> The ph sensor is in 0x65 address and other Atlas sensor in 0x64 >>> >>> debian@beaglebone:~$ i2cdetect -y -r 2 >>> 0 1 2 3 4 5 6 7 8 9 a b c d e f >>> 00: -- -- -- -- -- -- -- -- -- -- -- -- -- >>> 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- >>> 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- >>> 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- >>> 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- >>> 50: -- -- -- -- UU UU UU UU -- -- -- -- -- -- -- -- >>> 60: -- -- -- -- 64 65 -- -- -- -- -- -- -- -- -- -- >>> 70: -- -- -- -- -- -- -- -- >>> >>> Now I can write register with this script (can on/off onboard LED) but >>> when I try to read all 25 register I get this >>> >>> >>>> 1, 1, 0, 0, 0, 0, 0, 0, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, >>>> 0 >>> >>> >>> The first 2 bytes are the ID and FW, but I expect the rest to have >>> values such as the pH (registers 0x16, 0x17, 0x18, 0x19) but I am getting >>> only 0 (garbage) >>> >>> Python script >>> import smbus >>> import time >>> >>> class i2c_device: >>> def __init__(self, addr, port): >>> self.addr = addr >>> self.bus = smbus.SMBus(port) >>> >>> def write(self, byte): >>> self.bus.write_byte(self.addr, byte) >>> >>> def write_i2c_block_data(self, byte, array): >>> self.bus.write_i2c_block_data(self.addr, byte, array) >>> >>> def read(self): >>> return self.bus.read_byte(self.addr) >>> >>> def read_nbytes_data(self, data, n): # For sequential reads > 1 byte >>> return self.bus.read_i2c_block_data(self.addr, data, n) >>> >>> ph = i2c_device(0x65, 2) >>> ph.write(0x00) >>> i=0 >>> while (i <= 25): >>> print(ph.read()) >>> time.sleep(0.5) >>> i+=1 >>> >>> >>> >>> >>> On Thursday, June 15, 2017 at 10:38:28 PM UTC-4, Graham wrote: >>>> >>>> OK. >>>> Let's start with some background information. >>>> What model of Beaglebone? >>>> What version of OS, kernel? >>>> Which version of Python? >>>> How is the pH sensor hooked to the Beaglebone? >>>> What Voltage are you using to power the pH sensor? >>>> >>>> Now some basics to see if the I2C bus is running >>>> >>>> sudo apt-get install i2c-tools >>>> >>>> now run >>>> i2cdetect -y -r 1 >>>> what do you get? >>>> >>>> now run >>>> i2cdetect -y -r 2 >>>> what do you get? >>>> >>>> When you say that you get "garbage" what do you mean? >>>> What do you actually get? errors? tracebacks? obviously wrong data, but >>>> no reported errors? >>>> >>>> --- Graham >>>> >>>> == >>>> >>>> On Thursday, June 15, 2017 at 5:38:58 PM UTC-5, Sebastián Sáez wrote: >>>>> >>>>> >>>>> Hi, >>>>> >>>>> I'm writing a python script to communicate via i2c with the ph oem >>>>> sensor from Atlas Scientific. >>>>> >>>>> https://www.atlas-scientific.com/product_pages/oem/oem_ph.html >>>>> >>>>> https://www.atlas-scientific.com/_files/_datasheets/_oem/pH_oem_datasheet.pdf >>>>> >>>>> I already tried with the i2c module of mraa and smbus without luck. >>>>> Now I am trying to translate this arduino example from Atlas to python >>>>> but I read garbage >>>>> >>>>> >>>>> Any suggestions?, attached the full example arduino code >>>>> >>>>> >>>>> *Atlas arduino code* >>>>> byte i2c_device_address=0x65; >>>>> byte starting_register=0x00 >>>>> byte device_type; >>>>> byte version_number; >>>>> Wire.beginTransmission(i2c_device_address); >>>>> Wire.write(staring_register); >>>>> Wire.endTransmission(); >>>>> Wire.requestFrom(i2c_device_address,(byte)2); >>>>> device_type = Wire.read(); >>>>> version_number = Wire.read(); >>>>> Wire.endTransmission(); >>>>> >>>>> >>>>> *My python script* >>>>> import smbus >>>>> >>>>> # General i2c device class so that other devices can be added easily >>>>> class i2c_device: >>>>> def __init__(self, addr, port): >>>>> self.addr = addr >>>>> self.bus = smbus.SMBus(port) >>>>> >>>>> def write(self, byte): >>>>> self.bus.write_byte(self.addr, byte) >>>>> >>>>> def read(self): >>>>> return self.bus.read_byte(self.addr) >>>>> >>>>> def read_nbytes_data(self, data, n): # For sequential reads > 1 byte >>>>> return self.bus.read_i2c_block_data(self.addr, data, n) >>>>> >>>>> ph = i2c_device(0x65, 2) >>>>> ph.write(0x00) >>>>> device_type = ph.read() >>>>> version_number = ph.read() >>>>> print(device_type) >>>>> print(version_number) >>>>> >>>>> >>>>> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to a topic in the >> Google Groups "BeagleBoard" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/beagleboard/Lyxv7E3yIvs/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/589b19eb-9c6a-4ed9-aca3-3f3f1241ed4b%40googlegroups.com >> >> <https://groups.google.com/d/msgid/beagleboard/589b19eb-9c6a-4ed9-aca3-3f3f1241ed4b%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> >> For more options, visit https://groups.google.com/d/optout. >> > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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