Which Pins on the PXB are free for use? Is that right, that the Pins 1-30 at row b are free for use(page 42 technical reference)? I need 30 free Pins for conecting my hardware, but i didnt understand the technical reference at 3.5 with the multiplexing. What is Peripheral a and b?
Thanks
Re: Portux 920t Pin Question
Row B is far from being free for use. Row b is the CPU-bus and already used for Flash and SDRAM, you don't want to break that. They can be used as CPU-Bus with one of the chipselects though.
In principle all GPIO-Pins are free to use, except PA25/PA26, which are used by the I2C clock on portux and can only be used for i2c (or the RTC doesn't work anymore) and PC00 and PC01 which are used for the LEDs on the portux module. You can opt to use them anyway of course.
In general all pins of AT91RM200's PIO-controller are multiplexed: You can use them either as GPIO or Peripheral A or as Peripheral B. That means the Pin is assigned as GPIO or assigned to one of the AT91RM9200 internal peripherals. But never to both at a time.
Re: Portux 920t Pin Question
That means i couldnt use D0-D15 and A0-A25, because they are used for Flash and SDRAM. So i have to use some other PINS for my hardware? But at 5.2 (Technical Reference) the A0-A22 and D0-D15 have no device(i think they are not multiplexed), so i think i can use these PINS?!
Thanks
Re: Portux 920t Pin Question
These pins always belong to the EBI, they cannot be configured otherwise. So you cannot use them like GPIO pins. The only way to use them is by adhering to the bus protocol of AT91RM9200 and using one of the free chip selects (as already written). If you don't, flash and SDRAM stops working.
So you should try to find other free pins, if it does not match your requirements.
Re: Portux 920t Pin Question
This means, that i can use each pin, who isnt used by the portux? For Example using PA4-PA6 as gpio because they arent used by portux?
Re: Portux 920t Pin Question
Exactly, these pins are SPI chip selects or PCK1, TDX3 and RXD3. If you don't need them to be these peripherals, you can use them as GPIO pins.