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TTL Input Pin on E1

Posted: Sun Oct 12, 2014 11:06 am
by ClaireE47
Hi,

I wanted to use a TTL input on one of the E1 pins as a hardware input for one of the pre-existing programs
e.g. a hardware input for the integrator reset for the PID.
Would I have to assign the pin to the PID in the FPGA? Or is it possible to do in the C code/controller?

There seems to be a lot of code in red_pitaya_top.v and red_pitaya_hk.v about the extension connecter for the 16 GPIO pins - is that for future developments and is unused now? If I wanted to specifically allocate one of the 16 pins in the Verilog, could I comment this out?

Thanks for your help

Re: TTL Input Pin on E1

Posted: Sun Oct 12, 2014 4:40 pm
by Nils Roos
As far as I can tell, the expansion connectors are already fully functional.
If you want to use them from (userspace-)software, take a look at the list of control registers. mmap() the housekeeping subsystem's address space (0x40000000 - 0x400fffff) on /dev/mem and you can use the "Expansion connector ..." registers to interface with the pins.

If you'd rather do it within the fpga, you could separate one or more of the IOBUFs "i_iobufp/n" from its internal connections to the HK and wire them to the PID instead.

Re: TTL Input Pin on E1

Posted: Mon Oct 13, 2014 11:18 am
by ClaireE47
Thanks :) I was able to use the pre-existing functionality