[Emc-developers] Mesa 7i90 and 7i43 EPP mode

[Bertho Stultiens]

Hi,

Is there a way to detect the difference between the 7i90 and 7i43 boards
over EPP communication? I was looking into these drivers and they are
essentially the same (very small difference if you take the variable
naming out of the picture).

I have been pondering to add yet another RPI driver doing EPP emulation
on the GPIO pins. It would at least as fast as SPI communication and has
the potential to be faster (especially if the EPP slave relaxes the
timing a bit).

The advantage of EPP emulation is in the reduced frequency on the
pysical communication lines and would be at least four times lower. The
physical bottleneck would be on strobe-timing. That may be an advantage
in noisy environments and the overhead on the RPI is not any greater
than using SPI (which is also polled in a busy-loop).

If both 7i90 and 7i43 can be differentiated over EPP at runtime, then a
unified EPP driver is more easily created. Otherwise you need a module
parameter to distinguish or duplicate most of the code.

Any comments, thoughts or suggestions?

[andy pugh]

Post by Bertho Stultiens
If both 7i90 and 7i43 can be differentiated over EPP at runtime, then a
unified EPP driver is more easily created.

I think I once saw a hm2_epp driver, I wonder where it went?

[Peter C. Wallace]

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