Hi Benjamin, I can see that your layout was done for easy of routing with minimal feed throughs. Only once I plopped the CAN transceiver onto the schematic and used a copy of one of your resistors did I realize you'd used 0403 parts. I've soldered as small as 0602 by hand but not sure I want to try the smaller ones. Since 8 pins of the parallel port are outputs no matter what I'm thinking two SOIC 8 channel level translators are a more effective use of board space since the other 5 outputs also can use part of those. My goal is to create a cape that has these which exceed what is available on the standard single parallel port Outputs: 4 x STEP/DIR --> X,Y,Z and A 1 x Spindle STEP/DIR or PWM/DIR 1 x Enable (One signal Open Collector active high, one signal Open Collector low) 1 x Mist Coolant 12V relay driver 1 x Flood Coolant 12V relay driver Inputs: 1 ESTOP input (Pin 10 on the DB-25) 5 Limit/Home (X,Y,Z,A Home + Combined Limit) 1 FAULT input 1 High Speed Encoder A,B and I 1 Low speed Encoder A,B for MPG. I/O combinations. 1 x CAN bus (Tx/Rx for CANopen) 1 x UART (Tx/Rx for MODBUS or Nextion LCD Screen) 1 x I2C for LCD Touch Screen 1 x SPI for LCD Screen and I/O (includes 2 outputs for mux to Chip Select 4 devices). This all has to exist on one board at a cost far lower than the MESA Raspberry interface board or there's just no point to it. MachineKit has demonstrated that we can use the PRUs in the Beagle to deal with both spindle encoders and higher speed stepping. So theoretically the above list implemented on a cape that has pluggable screw terminal connections to run a small CNC mill or Lathe with MachineKit and a USB hub for mouse, keyboard, USB stick (G-Code transfer) and USB based Pendant. If that sort of board could be built for under $100 then there's hope for the BBB. And the SPI, I2C, CAN and UART allow expansion to an 800x600 LCD display, Keypad and things like VFD (ModBus) and Tool Changer (CANopen or MODbus). And if someone wants more than that the better solution is a PC with full MESA expansion boards. If you are retrofitting some sort of mill that uses +/- 10V control with an encoder or resolver Jon Elson and others have LinuxCNC solutions that again are a better solution. The market for BBB and 3D printers is gone. Other than as an exercise. I use a a Pi2B (I think) Octoprint and the Arduino Atmel based controller. It prints what I need. The BBB with Replicape will eventually end up controlling my POS Delta printer if I ever get the rest of the mechanical issues sorted out. But past that. The opportunity for a BBB with a CNC cape is really that group of people who don't want CNC on their mill but do want a DRO and power feed. And if you suddenly plugged in an Ethernet connection to something running on the latest high tech hardware you have full Linux or MachineKit CNC. If you want. John Dammeyer From: machinekit@googlegroups.com [mailto:machinekit@googlegroups.com] On Behalf Of Benjamin Balga Sent: April-04-20 1:53 AM To: Machinekit Subject: Re: [Machinekit] Re: Breakout board for BeagleBone Black (BBB) Hello, I'm also interested by what you can come up with. My goals with my "BBB-DB25-CNC-Cape" were to have a simple board with 5V compatible IOs that can be expanded upon, using only the "truly free" I/Os, and obviously not full-featured because I don't need it and it's hard to get it right. The cape routes one hardware encoder to the DB25 header, might be fast enough for a spindle encoder. I ordered some boards a few days ago, hopefully they will arrive soon-ish. If I were to redo it one day, I would probably maximise the 5V I/Os and use several 10-pin or less headers that can be each connected to "single-job" breakout boards in a very modular fashion. That way adding or swapping features is easy. Like a direct ribbon-to-driver adapter, ribbon-to-spindle adapter, ribbon-to-home-and-limit-switches, ribbon-to-magic... Dang I want that badly now xD Cheers, Benjamin
Le samedi 4 avril 2020 06:28:11 UTC+2, John Dammeyer a écrit : I'm about halfway through modifying the cape PC board. Correct me if I'm wrong but because the BBB has internal flash it's expected that the OS and all run on that. That then frees up the pins on P8 marked MMC1_-- ? I'm basing this off the charts from www.ExploringBeagleBone.com. I have both editions of the Derek Molloy's book. I've added a CAN driver to the cape and I'm going to shift some pins down so the I2C pins can be brought to the header. What I'd like on the first connector is standard I/O and PWM out for spindle. Maybe even add the circuitry to create 0-10VDC. But there aren't enough pins on a standard parallel port to be able to do a spindle encoder or mpg. That's why I was looking at the RS232 and connecting to something like a MODIO or for that matter something similar that runs on CAN bus with CANopen protocol. If you can afford it there are some pretty nice robust displays with CANopen or J1939 used for industry. More as I work out what I'm trying to accomplish. John From: machi...@googlegroups.com <javascript:> [mailto:machi...@googlegroups.com <javascript:> ] On Behalf Of Rob M Sent: April-03-20 7:05 PM To: Machinekit Subject: [Machinekit] Re: Breakout board for BeagleBone Black (BBB) I did the same when I did mine....had a lapse along the way and screwed up the signal to pin mapping. As long as the daughter boards match the cape no probs. In my defense I was looking after a Beagle pup we got at 8 weeks old. There's also the raw pins brought out for the ADC, an I2C bus and for an external power switch. I don't know if you've seen my spread sheet but I've thrown it up (hopefully without any major typos). With a bit more thought some pins would have been better elsewhere, but I was aiming at a simple conversion from a 2 port PP setup. Hence the "output daughter board" resembling a Std PP and the Input resembling a PP setup for input. I figured that the main cape could be used on it's own for experimenting with external devices without the daughter board. But I'd be interested to see your progression, as I have time on my hands now as I stopped the Linuxcnc Mint ISO's, the devs prefer seem just to support Debian. So you want someone to bounce ideas off my old noggin is pretty hard & dense. Cheers Rob -- 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 machi...@googlegroups.com <javascript:> . To view this discussion on the web visit https://groups.google.com/d/msgid/machinekit/2bfd00d0-0278-4eb4-b8ab-484205f74260%40googlegroups.com <https://groups.google.com/d/msgid/machinekit/2bfd00d0-0278-4eb4-b8ab-484205f74260%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 machinekit+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/machinekit/bde4bfae-a854-4c64-885f-d940001bab09%40googlegroups.com <https://groups.google.com/d/msgid/machinekit/bde4bfae-a854-4c64-885f-d940001bab09%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 machinekit+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/machinekit/08a701d60ab3%24d718d180%24854a7480%24%40autoartisans.com.
