Since I'm sitting around trying to figure out what to do with myself due to this COVID-19 I thought I'd put together a spreadsheet that shows how the pins are used on my Xylotex BBB_DB25_26 and how they are on the BBB-DB25-CNC-Cape. There are issues with both of them. The Xylotex is no longer made and what they sell now is more like the CNC although I've not yet looked at what pins are used for what. What is missing is the ability to access the CAN bus and no I2C pins brought out for external devices. What's in the spread sheet is preliminary in the sense that I've not even assigned pins for the step/dir and inputs. The Xylotex would have to lose the Home A in order to have a series string of limit switches. Ie. The Home switches for each axis can also be Limit at the Home position end. And then the other end a string of N/C switches in series. Martin Berriman added an encoder MPG but his pins also interfere with some of the others on these two capes. Assigning the two inputs to free pins not used by some of the standard CNC signals but capturing the channel # and distance to step could be done from an SPI expansion I/O set of chips. I don't know if the software polling of the encoder is fast enough for a spindle encoder but if power tapping was required then we definitely need to add that feature too. All that says is that making up a BBB Break Out Board Cape should probably have either a second DB-25 to expand the I/O or just forget the DB-25 completely and create an actual cape that is also a Break Out board for a 4 Axis Mill. Complete with MPG support, Spindle Encoder Support, Home/Limit switches, CAN bus for say CANopen peripheral/motor expansion, RS232/485 for VFD control for spindle speed if the 0-10V output isn't available. And in fact this sort of BoB should have a 0-10V with DIR signal for the spindle. It also needs to be able to deal with FAULT/ENABLE signals in order to disable/reset a drive that has faulted or for that matter an ESTOP in automatically sets the ENABLE false. That pin output should probably be available as both an active high and active low. So much more I/O would be available if the Beagle did not use the HDMI LCD_DATA interface occupying much of the P8 connector. Looking at the NEXTION displays that are run from an RS232 port is one option. Or using SPI and I2C based signals for an LCD display that uses the LittlevGL library. I've been looking into that one with an ESP32. But in many ways it would be easiest to keep the HDMI, slow as it is, with the MachineKit code inside the BBB. At least as a first step and just make it so the I/O on the LCD pins is available for expansion and a MachineKit version that uses Ethernet to something else for the standard AXIS type user interface. John From: [email protected] [mailto:[email protected]] On Behalf Of Benjamin B (BBenj) Sent: March-22-20 7:50 AM To: Jirí Procházka; Machinekit Subject: Re: [Machinekit] Re: Breakout board for BeagleBone Black (BBB) Hello Jiri, I finally took some time to finish the PCBs, and upload everything, with some infos : https://github.com/GIPdA/BBB-DB25-CNC-Cape I didn't ordered anything yet, but I'll let you know when I have something tested and operational. Cheers, Benjamin Le 18 mars 2020 à 12:24:06, Jiří Procházka ([email protected]) a écrit: Hey Bejnamin, I would definitely be interested. There is no need to rush, because we are confined too (Czech Republic). If you gave the files I would definitely give you some contribution to your project and feedback from my testing. And for sure let me know when your cape is tested. Thanks Jiri -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to a topic in the Google Groups "Machinekit" group. To unsubscribe from this topic, visit https://groups.google.com/d/topic/machinekit/f1JJBTSNuVI/unsubscribe. To unsubscribe from this group and all its topics, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/machinekit/457b4481-bc67-40e8-8502-3f10cb9e56ab%40googlegroups.com <https://groups.google.com/d/msgid/machinekit/457b4481-bc67-40e8-8502-3f10cb9e56ab%40googlegroups.com?utm_medium=email&utm_source=footer> . -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected] <mailto:[email protected]> . To view this discussion on the web visit https://groups.google.com/d/msgid/machinekit/CAGiu9V-%3DVQjip2P%2B9Nf7WBdY743QwYzuO0EM62XTjQn9yb67mg%40mail.gmail.com <https://groups.google.com/d/msgid/machinekit/CAGiu9V-%3DVQjip2P%2B9Nf7WBdY743QwYzuO0EM62XTjQn9yb67mg%40mail.gmail.com?utm_medium=email&utm_source=footer> .
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BBB_Cape_Pins.xlsx
Description: MS-Excel 2007 spreadsheet
