Hi
A design engineer asked me if it should be ok to have an 1-bit GPIO in MicroBlaze design, well yes I answered - after a short while.
But I am trying to use a single bit GPIO instance to capture the PENIRQ signal from Analog Devices touch screen digitizer and well it all doesnt seem to work. Ok, make then then GPIO port 2 bit wide and use only one?
That was yesterday. This morning I looked at the oscillocope capture of the pulse on the PENIRQ - active low level was above 2 Volt.
Signal coming directly from Evaluation Board from Analog Devices, FPGA disconnected from the signal!
Let me see the eval board schematics! Schematic shows 50K pullup on PENIRQ and no other connections.
I guess its fitted with 50ohm I say. (assuming the SMD assembly guy at Analog Devices messed up).
No I dont belive this, sure the board has passed testing at Analog Devices, see here is a even label: "Test passed"!
Well lets measure!
And exactly 50ohm it was!
Not even a SMD but old style through hole resistor! Sure a 50 ohm pullup on output specified for 10k-100k pullup would disable the low level driving capability.
Why I am writing this to the newsgroup?
To give some earned credit to Xilinx - if there are more critical posts about Xilinx chips or software, then it actually means there is huge useage of them, and as we know things happen. So more (angry) posts means more users, not that there is a reason to be angry. Less posts doesnt mean better products or services, just less users.
It doesnt mean that I am completly happy with Xilinx software, but OTOH I am not easy to please on tech matters.
Would I have posted yesterday, I could have been angry to EDK that doesnt properly implement a GPIO with 1 bit width.
Today the situation is different, the issue is not with EDK at all.
Hope this 1-bit resistor story triggered a few smiles today :)
Antti Lukats