Raspberry Pi 4 with Mesa 7c81

Thanks for your support. I would prefer to have the 7 stepgen available, and not the serial.

 

Where you able to get the Mesa 7c81 working with the Match3 board, and if so how did you do it?  Thanks,

I’m just getting started with LinuxCNC, with an end goal of running it on a Raspberry Pi (4B or 5), and driving stepper motors on my rose engine lathe. 

I have LinuxCNC running on a Raspberry Pi 4B which is connected to a Mesa 7c81 board.  I assume each stepper motor will need a driver and currently have each one hooked up to a StepperOnline DM542T.

The current gap I’m trying to fill is how to get from the Mesa 7c81 board to the 5 StepperOnline DM542Ts (Spindle, X, Z, A, & C).  In particular, I am at a loss on how to get the 3 needed signals to the DM542Ts:  Step, Direction, & Enable. 

I am seeking some guidance on where to find instructions or manuals which can me help get started.  I recognize that this is probably a very basic set of questions, so I appreciate whatever help can be provided to point me in the right direction. 
 

Typically you would use a breakout board like the common "5 Axis Mach" BOB
and not connect directly to the 7C81s ports

richcolvin wrote:

The current gap I’m trying to fill is how to get from the Mesa 7c81 board to the 5 StepperOnline DM542Ts (Spindle, X, Z, A, & C).  In particular, I am at a loss on how to get the 3 needed signals to the DM542Ts:  Step, Direction, & Enable. 

I am seeking some guidance on where to find instructions or manuals which can me help get started.  I recognize that this is probably a very basic set of questions, so I appreciate whatever help can be provided to point me in the right direction. 

 

Have you found the 7C81 manual?   www.mesanet.com/pdf/parallel/7c81man.pdf

Though admittedly that doesn't really answer your questions, because the functions of the various chips depends on the firmware flashed to the 7c81. 

There are a number of possible firmwares, but it is probable that the one you have is good enough for your purposes. 

There are two ways to identify which signals are on each header pin of the 7C81. You can use mesaflash, or you can run a LinuxCNC HAL command line session. 

Starting with the HAL method, this will also check that LinuxCNC comms to the board are working. 

Open a terminal. 

If all it well, this should connect to the Mesa board, and give you a list of what function is on which IO pin. 

You can then continue with additional HAL commands, for example 

When finished:

The other way is with mesaflash. You might need to install this: "sudo apt-get install mesaflash"

(This might need to tbe "sudo mesaflash")

Report back what the results are, there are a number of possible hurdles to either of these working immediately.