subject:"\[beagleboard\] Re\: i2c python"

Re: [beagleboard] Re: i2c python

2017-06-17 Thread Graham Haddock

Sounds like you can move ahead, and learn a little python.
--- Graham

==

On Fri, Jun 16, 2017 at 4:01 PM,  wrote:

> now I can read :)
>
> this script works
>
> 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_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)
> ph.write_i2c_block_data(0x05,[0x00]) // off LED
> print(ph.read_nbytes_data(0x00, 25)) // read all registers
>
>
>
> On Friday, June 16, 2017 at 1:34:04 PM UTC-4, Sebastián Sáez 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
>>>
>>>
>>> 
>>>
>>> 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

[beagleboard] Re: i2c python

2017-06-17 Thread ssaez

now I can read :)

this script works

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_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)
ph.write_i2c_block_data(0x05,[0x00]) // off LED
print(ph.read_nbytes_data(0x00, 25)) // read all registers



On Friday, June 16, 2017 at 1:34:04 PM UTC-4, Sebastián Sáez 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
>>
>>
>> 
>>
>> 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();

Re: [beagleboard] Re: i2c python

2017-06-16 Thread Sebastián Sáez

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  > 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
>>>
>>>
>>> 
>>>
>>> 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:
>
>
>

Re: [beagleboard] Re: i2c python

2017-06-16 Thread Graham Haddock

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  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
>>
>>
>> 
>>
>> 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();

[beagleboard] Re: i2c python

2017-06-16 Thread Sebastián Sáez

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
>
>
> 
>
> 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

[beagleboard] Re: i2c python

2017-06-16 Thread Sebastián Sáez

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



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 the Google Groups 
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to beagleboard+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/beagleboard/7d432a83-cd28-498e-bf3f-40ba7f5627a8%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[beagleboard] Re: i2c python

2017-06-15 Thread Graham

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 the Google Groups 
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to beagleboard+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/beagleboard/4e302bea-d05f-4cb9-bc4f-55de94d496be%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Re: [beagleboard] Re: i2c python

[beagleboard] Re: i2c python

Re: [beagleboard] Re: i2c python

Re: [beagleboard] Re: i2c python

[beagleboard] Re: i2c python

[beagleboard] Re: i2c python

[beagleboard] Re: i2c python

7 matches

Site Navigation

Mail list logo

Footer information