PiRack problem

Hi,

For the sake of completion we now understand the issue and can provide the various solutions for when using a PiRack to link one or more PiFace boards to the R-Pi..

When shipped the PiRack has the set of Jumpers J1/J2, J3/J4, J5/J6 and J7/J8 set as either 'Default SPI CE' or 'Swapped SPI CE Lines'. The documentation accompanying the PiRack states that the SPI CE lines do not need swapping i.e. implying that they are set as 'Default SPI CE'.  If that was the case then the associated initialisation call in any Python code that is expected to drive the PiFace would have the line 'pfio.init()' - assuming the corresponding import assigns the module to the object identifier 'pfio'.

Unfortunately, the PiRack appears to be shipped with the J1/J2 etc. jumpers configured as 'Swapped SPI CE Lines'.  Hence the resulting 'pfio.init()' call results in the report of NO PiFace being detected.  This can be resolve by one of two ways:

1) Swap ALL the J1/J2, J3/J4, J5/J6 and J7/J8 jumper settings on the PiRack back to 'Default SPI CE';

OR

2) Change the 'pfio.init()' call to 'pfio.init(True,0,1)'.  The 'pfio.init()' call is the same as writing 'pfio.init(True,0,0)'.  The first parameter (default=True) sets the inilisation of all boards to 'True', the second parameter is the SPI bus and the third is the chip_select value. It is the chip_select value that must be consistent with the J1/J2, etc. jumper settings.

The doumentation concerning the init() and other PiFace API calls is supplied in the 'pifacedigital.py' module.

When the PiFace is connected directly to the R-Pi i.e. without the use of a PiRack, then the Python code must use the call 'pfio.init()' otherwise the PiFace will not be detected.

One final point is that when using the PiRack is ESSENTIAL that you download and use the latest set of code libraries for the PiFace. If you use only the code link provided in the PiFace (i.e. to http://pi.cs.man.ac.uk/download/install.txt) then you will not be able to control the individual PiFace boards linked through the PiRack. You should download the latest 'pifacedigital' and 'pifacecommon' code modules from the R-Pi GitHub at: 'https://github.com/piface'.

If only one PiFace is linked to the PiRack, the. as long as the PiRack jumpers are set correctly AND the jumpers J1/J2 on the PiFace are set to identifiy the PiFace card as '0' then the PiFace will be correctly identified and driven if you use the original code libraries.

Colin S.

Hi Colin,

Thanks for putting the tips up - I have followed your instructions, updates my code libraries and am using option 2 above - however when I connect 2 PiFaces' to the PiRack when I address the first board, it actually does what I want on both boards, and when I try and address the second I get the error "pifacedigitalio.core.NoPiFaceDigitalError: There is no PiFace Digital with hardware_addr 1" - any ideas where I might be going wrong?

Many thanks,

Stuart

Hi Colin,

Thanks for putting the tips up - I have followed your instructions, updates my code libraries and am using option 2 above - however when I connect 2 PiFaces' to the PiRack when I address the first board, it actually does what I want on both boards, and when I try and address the second I get the error "pifacedigitalio.core.NoPiFaceDigitalError: There is no PiFace Digital with hardware_addr 1" - any ideas where I might be going wrong?

Many thanks,

Stuart

Stuart,

What versions of the PiFace Digital software libraries (Core and Common) are you using?

What are the J1-J8 addresses assigned to the cards and what order are the cards on the PiRack?

Colin S.

Hi Colin,

Thanks for your response, my pifacedigitalio is version 3.0.4 and pifacecommon is 4.0.0

In terms of jumper settings, if i'm honest i'm more of a software kinda guy so i've just attached an image of the board setup, but I am using it with the pfio.init(True,0,1) [as that seemed to be the only way it would work]. The 2 PiFace cards are the first and second in the rack and there is nothing else conntected.

Thanks again,

Stuart

Stuart,

We have had problems with the set of libraries you are using but you should be able to get the boards working.

You need to check that the J1-J2 jumpers on each of the PiFace Digital are set as '00' and the other as '01' (this ensures each board s addressed uniquely).

I suspect they are both in the '00' setting hence the clash.  If you make the change to '01' then the clash should be avoided.

We have a better description of how to set everything up on the Project at: LED Count Game Instructions

I strongly suggest you  revert to the pfio.init(True,0,0).

Let me know how you get on.

Colin S.

Hi Colin,

Following the PiRack jumper configuration images in the LED game project and reverting to pfio.init(True,0,0) - many thanks for your assistance.

Best wishes,

Stuart

Hi Colin,

Is there any update on this?

pifacecommon and pifacedigitalio look like they have not been updated since late last year.

Thanks

Dallas