I wanted to use this for a HiFi project, but it seems to use all the GPIO pins, and I need more pins for IR reciever and a small LCD screen, is this impossible or is there a way around it?
I wanted to use this for a HiFi project, but it seems to use all the GPIO pins, and I need more pins for IR reciever and a small LCD screen, is this impossible or is there a way around it?
A mention in another post says that the connection is a 4x2 patch of pins using some mechanism that sound vaguely like pogo-pins.
The audio card uses i2c from Raspberry Pi, and a single GPIO output, plus the lines form the P5 header. There are lines available (i2c is multidrop anyway).
1. If the user is not skilled with a soldering iron, there is unfortunately no mechanical access to the GPIO pins once the audio card has been plugged on to the top of the Pi. Also,
options to ‘stack’ the board using expansion options like PiFace Rack, are not possible either, because the Raspberry Pi P5 pins are needed make the board work. P5 is not part of
the expansion board specification.
2. With soldering skills, the user could demount the pogo pin header, fit an 8-pin header to his Pi, and fit one of the opposite gender to his sound card. Short ribbon cables could then
be constructed to join the two boards together, breaking out the GPIO’s required to drive display and IR receiver.
3. Again, with soldering skills, the relevant GPIO’s required can be taken from the back of the Pi with very fine and short flying leads.
Of course, all of the soldering options will invalidate any warranty in place for the Raspberry Pi and the Audio Card, but if you know what you are doing, should be fine. There is also a product called PiFace Control and Display that gives you the display and remote control options you might want, together with software required to drive it.
I have some experience with a soldering iron, but not much and it was a long time ago.
How difficult would it be to demount the old pin headers and fit the new ones?
Thanks for the reply
I did this to a PiFace Digital ... before the Pi rack was available.
It isn't hard to do, and you don't need to use 2 13 pin strips if you only want a few pins.
http://www.element14.com/community/roadTestReviews/1452
Mark
Really looking forward to this board.
It would be great if it were for sale with various header options such as:
A standard header .. or .. No header .. or ..
A stacking header such as this: http://www.adafruit.com/products/1112
If you wanted to minimize stock then just have the stacking header version & let the user cut of the extra length if it bothers them.
I'm currently using a pifacecad with my pi. I'm willing to forego the lcd and external buttons to use the wolfson audio card, but I''m not sure I could live without the IR receiver. Will an IR receiver module work with the expansion header of the wolfson card?
Thank you!
For my application I need some GPIO pins. I do quite a bit of soldering, so that's certainly not the problem.
Jonny wrote that "The audio card uses i2c from Raspberry Pi, and a single GPIO output, plus the lines form the P5 header. There are lines available (i2c is multidrop anyway)."
Not sure how Jonny got to that conclusion. I looked at the schematics available at this site and page 7 shows that all pins of the RPi header are connected to somewhere on the audio card. That might not necessarily mean that they are actually in use, but it makes any attempt with stacking headers or similar very dangerous...
Maybe i2c as multi-drop is ok.
Pin8 (GPIO14) is called RPI_TX and Pin10 (GPIO15) is called RPI_RX. Both pins appear to be connected only to the 3 pin header J8, so are basically available for getting direct connectivity to RPi GPIOs.
What's required is a confirmation that the pins are still available with the GPIO programming of the chip and that they're not in use by the software/driver. It would also be good to get some info on what their intended use was, is or will be in the future.
I just checked http://elinux.org/RPi_BCM2835_GPIOs . While other pins can be reprogrammed, Pin8+10 are only available for serial port data.
Assuming that there is no wolfson audio card specific use of the serial port planned, I mapped Pin8+10 from their default serial port mapping after reboot (ALT0 setting) back to GPIO14 + GPIO15. I successfully use one pin for input and one for output with my application.
The wolfson audio card also features on the extension header two GPIO pins (called GPIO3+GPIO4). It would be interesting to know if there is driver support planned to make the pins available in the same way as the standard GPIO pins. This would add two additional IO ports...
The schematic shows GPIO3+GPIO4 with annotations of [3] and [2,7]. Does anyone have any ideas what those might be referring to? Might they give a clue of how they might be accessed? Has anyone heard from Wolfson on this topic on any other boards? (Wolfson's web site doesn't seem to have its own support forum.)
It is a real shame that more of the RPi's GPIO pins aren't being passed through. I have a project I've been working on that I was hoping to add the Wolfson audio board to. However my project currently uses a bunch of GPIO pins. I can rework my project so I'm only using I2C plus two other GPIO pins, but that would be pretty much a bare minimum. Right now it looks like I need to choose between using the Wolfson board and the other features of my project.