ColorCNC Colorlight 5A-75E/5A-75B as FPGA controller board

Happy new year!

I have found 74LVC245A .. which old buffers to remove ? are all the same ?
U15/U12/U38/U20 are ok to replace ?
Exists some photo to show which buffer are connected to each idc16 connector ?

For the 5A-75E version 6 and 8, you can find which buffers to replace at  Chubby75 git repository :

Transceivers U23,U24,U28 completely cover RGB pins on J1,J2,J3,J4Transceivers U25,U26,U27 completely cover RGB pins on J5,J6,J7,J8Transceivers U14,U16,U18 completely cover RGB pins on J9,J10,J11,J12Transceivers U9,U12,U15 completely cover RGB pins on J13,J14,J15,J16

I do not recommend to replace the buffers for the shared pins. Each IDC connector has their own buffer, so this would lead to have them all replaced. 

which pins are shared ?
Must replace U23,U24,U28 U25,U26,U27 U14,U16,U18 U9,U12,U15 ?
or can replace only U23,U24,U28 for convert J1,J2,J3,J4 to inputs ?
Hot air works for desoldering or it is more safe to cut legs of old buffers ?

vre wrote:

which pins are shared ?

​​​​​Pons 1, 2  3, 5, 6 and 7 are individual pins. Pin 4 and 16 are ground. The remainder of the pins are shared pins. Of these shared pins, pin 8 (E) is special, as in some displays this one is connected to ground. 

Must replace U23,U24,U28 U25,U26,U27 U14,U16,U18 U9,U12,U15 ?
or can replace only U23,U24,U28 for convert J1,J2,J3,J4 to inputs ?

It will suffice to replace only U23, U24 and U28 in this case. When using mij  breakout boards  I recommend to replace the buffers in groups of 3 to prevent 'wasted' pins. 

Hot air works for desoldering or it is more safe to cut legs of old buffers ?

I do have a hot air station. My experience with using this to desolder buffers is not good, pads are coming loose from the board. This might also be due to my lack of skill. 

With cutting the legs I've never had any problem, so I deem this method safer. 

Hello Together again - I have found now a solution in my Joint Following Error on the Z Axis
At Fabios Github repo (github.com/faeboli/Lcnc/blob/master/supp...cncMill/LcncMill.hal)
 I have copied his configuration to test my steppers.
I found an Error in the LcncMill.hal File:# Joint 2 setup   setp Lcnc.00.stepgen.00.scale [JOINT_2]SCALE setp Lcnc.00.stepgen.02.acc_lim [JOINT_2]STEPGEN_MAXACCEL # setp Lcnc.00.stepgen.00.enable true
so i have changed the stepgen.02.acc_lim to stepgen.00.acc_lim and now i have no more Joint Following Errors. Maybe if some tried also this configuration it helps a little bit =) (Maybe also Fabio can change this error in the GitHub Repo)

Another Question: Are the Outputs from the stepgen Step/Dir +3V3? so can I  connect it to a stepper driver (STEP/DIR)and only need a ground
Pin? or is this Inverted?



 

The 5A-75E has 5 Volt outputs (therefore they have those buffers). Depending on your driver you can van connect these directly. I know Leadshine, Polulu, Lichuan can. Please refer to their documentation.

Okay thank you for the quick reply - I have a 5a75b.
I was only a little bit confused because there are no step and dir pins connected by the joints in the hal file. 
I know only a little bit about PID - So for my Understanding the PID gives the command to the FPGA and the FPGA produces the Step/Dir signals which goes to the Buffers- right?

Not to make it more complex: your understanding is roughly correct.

If you don't like the PID and tuning of it, you might also want to try  Litex-CNC  and it's pos2vel component. 

Thanks for your information - Yeah I have no idea how to tune the PID for STEP/Dir or what exactly to do with it. Maybe i`ts better to try Litex-CNC - does anybody or maybe you have a instruction or maybe a hal and ini File for LitexCNC with a Stepgen?

Edit: I have read the readme of LitexCNC - so i have to build a new Firmware. (And can I take the same Firmware (LCNC from Fabio) from the FPGA or do I have to make a new Bitfile for Litex-CNC as well?)

The functionality of both is the same. However, the information transferred is not. You have to rebuilt the firmware.

For Litex-CNC the configuration is done using JSON-files. Some examples of these files are given on the documentation page. You can download them, verify the settings and built them. If you want, I can make a specific config for you as well this evening. Need to know the number of gpio in / out, stepgen, pwm and encoders.

On the documentation there are also examples of the HAL files available per module. 

I tried to make Litex-CNC as user friendly as possible. It is installable from PyPi.org:
To install the driver, litex and toolchain
When you have your configuration, you can build it using the command:
After that you can upload the generated bit-file to your board and start connecting your HAL.

Per module there is an example on how to design your HAL file. An example for stepgen is given here . I only noticed just now that the documentation for encoders is missing. Will add that soon.