Python 3 and SPI lib updates

[lucassarcanjo]

I'd include some modifications to run the project on python 3 environment (minor changes). I also modified some functions of read/write SPI, that were changed by LThiery (author of spi library of this sensor library).

[victormagalhaess]

Thank you so much!

[rami85]

Hi Lucas,

I tried to run your fork with SPI and Python3 modifications but I still get this error:

python Read.py

/home/pi/.../test/MFRC522-python/MFRC522.py:133: RuntimeWarning: This channel is already in use, continuing anyway.  Use GPIO.setwarnings(False) to disable warnings.
  GPIO.setup(self.NRSTPD, GPIO.OUT)
Traceback (most recent call last):
  File "Read.py", line 41, in <module>
    MIFAREReader = MFRC522.MFRC522()
  File "/home/pi/.../test/MFRC522-python/MFRC522.py", line 135, in __init__
    self.MFRC522_Init()
  File "/home/pi/.../test/MFRC522-python/MFRC522.py", line 406, in MFRC522_Init
    self.MFRC522_Reset();
  File "/home/pi/.../test/MFRC522-python/MFRC522.py", line 138, in MFRC522_Reset
    self.Write_MFRC522(self.CommandReg, self.PCD_RESETPHASE)
  File "/home/pi/.../test/MFRC522-python/MFRC522.py", line 141, in Write_MFRC522
    spi.transfer(((addr<<1)&0x7E,val))
TypeError: function takes exactly 2 arguments (1 given)

Last version of SPI is installed and pins are connected correctly as documentation explains.

Do you have any idea of that issue? Thanks in advace Lucas.

Regards.

[lucassarcanjo]

Do you have any idea of that issue? Thanks in advace Lucas.

Hi @rami85, See the modifications that I did in MFRC522.py. The last update of SPI-Py lib changed the number of arguments in some functions.

The old way (your code on line 141):

spi.transfer(((addr<<1)&0x7E,val))

The new way:

spi.transfer(self.dev_dictionary, ((addr<<1)&0x7E,val))

Take a look at Files Changed tab. With slightly changes in lines 131, 141 and 144 your code must run 😄

[rami85]

Thank you Lucas, I cloned the master brach instead your fork.

However, I found a couple issues:

on line 310 on MFRC522.py:

print("Size: ".format(ackData[0]))

As you see, you lost a 'b'. It should be:

print("Size: ".format(backData[0]))

On the other hand, when the Read.py reads tags, the script prints:

Card detected
Card read UID: %s,%s,%s,%s
Size:
Sector 8 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

So.. it seems there is another bug on Read.py script.

Regards.

[marvin-kolja]

So.. it seems there is another bug on Read.py script.

Hey @rami85, I found what the bug is.

The old python formatting is using: print "%s" % example The new one should be: print("{}".format(example)

I will change those things and upload a new version.

Best regards,

Marvin

[ukleinek]

Converting to python3 is also part of #78 and #28.

[xenomorpheus]

Hi All. I an probably missing something here. Are we waiting for @mxgxw to approve the pull request?