Raspberry Pi 4

PCW wrote:

russell wrote: Hi,
I'm in the process of moving my lathe over from MachineKit on a BBB to LinuxCNC on a RPI 4 with a Mesa 7c80, I've had to use master to get the INMUX support for the inputs but I'm now stuck setting up the spindle enables and direction outputs. I've got the motor drivers direction and enable inputs connected up to the Spindle Enable and Spindle Direction terminals on TB5 but I can't see anyway of triggering them from HAL - am I missing something?

Regards
Russlel

Yeah missing a better manual...

The spindle analog enable is part of the PWM hardware so enabled when
the PWMGen is enabled

The Optocoupler ENA (or forward) output is controlled by GPIO 20

The Optocoupler DIR (or reverse) output is controlled by GPIO 21

These are both active low so you would want to set both the is_output parameter
on both GPIO bits and set invert_output parameter on the enable pin
(and possibly on the dir pin depending on how the drive direction works)

Thanks. I've got most things working how I want them now, but I've got a couple of spare rotary encoders which I would like to try and use to improve the homing accuracy, it's only a small lathe so neither axis moved particuetly fast so I think the MPG inputs on the 7c80 would be fast enough but they are missing the index support. Is there any way of adding the missing functionality? Alternatively can I somehow connect then to the P1 header?

Regards
Russell

The MPG encoders are really intended just for that use.
Adding an index would need new firmware and driver support.

You can use the expansion port for additional encoder channels, but the bare
pins are susceptible to damage from overvoltages, so if you dont want to add one of
Mesa's fancy daughtercards, at the minimum you should add a 220 ohm or so
series resistor to any external wiring.

I don't mind buying a Mesa daughter card except that I will have to import one as they are not available in the UK, so I would like to do some proof of concept testing first.

I do have an old buffered parallel port break out board knocking around I could use but how do I configure the hostmot2 component to tell it about the new encoders?

Is the 7I85 the most appropriate card to add 2 encoders?

Thanks
Russell

We are using the 7i81. it has 3 26 pin connectors. It works quite well with our 3 axis cnc.

7 i ??

7C81

Yes the 7C80 and 7c81 are new and specialized for the Pi