The sixteen bits of non-isolated digital I/O connect directly
to the FPGA buffered by a FET. When configured as inputs they are +5V tolerant.
When configured as outputs refer to the ECM carrier card manual for FPGA drive
strength.
Each I/O is passively pulled down to Ground on power up or
when the FPGA is tri-stated. Typical channel resistance for the FET buffers is
about 5 ohms. Note that although a ground is shown in the block diagram, no
grounds are provide by P/N 5235 itself. Instead most ECM carriers provide
spare grounds for that use.
Since this board does not provide input hysteresis,
debouncing of input signals should be performed in software or the FPGA. A
serial identification circuit prevents use with incorrect FPGA IP.
Typical Digital I/O
applications include driving small loads such as LEDs, mechanical switch
interface and general purpose digital I/O.
Datasheet
http://www.technobox.com/Datasheet-ECM-5235-Digital-4pgv1-A80401-press.pdf
micro mezzanine system electrical conversion module digital i/o sixteen bits 16
bits Technobox 5235
