Remora for RP2040

Picobob was designed during the height of the chip shortage so used more or less the most basic parts I could find. Transistors are cheap and since there are 12 lines you would need either two chips or waste lines on a 16 channel. This is why the inputs are inverted, that was the most available Schmitt trigger input IC I could find. There are still supply issues with simple 5V nononverting buffers as I had to special order parts to build our PicoHAL board.

I will have a look at the other requests but i did want to keep the pinout pretty close to the existing picobob to avoid ripping things up too much and to preserve the performance that it gets with the GRBLHAL PIO stepper code.

Also just checked and the cost of the 12 transistors is about a tenth or less the cost of the 74series buffer/translator to accomplish the same task here.

Thanks for explanation, totally get it.

Did you populate the boards yourself or use someone like JLPCB? Hoping you share the files etc like the PicoBob so I can get a few of these made for testing and Remora RP2040 development.

For sure you can get PicoBOBs (including the new design) fully assembled by JLC quite easily. This is kind of our thing, we are trying to build things for everyone to build and use, not just prototypes. If we post the board the files will be available just like all our CNC designs under the CERN license.

Just keep in mind there is not a lot of overhead on the 3.3V rail. It is designed to power the PicoBOB, not other things. Is there a schematic available for the pendant you want to use?

media.digikey.com/pdf/Data%20Sheets/ON%2.../2N5551,MMBT5551.pdf

Current - Collector (Ic) (Max) 600 mA

Voltage - Collector Emitter Breakdown (Max) 160 V

vs far lower for the SN74ALVC164245
www.ti.com/lit/ds/symlink/sn74alvc164245.pdf

Which do you think will last longer in a machine environment?

drewnabobber wrote:

For sure you can get PicoBOBs (including the new design) fully assembled by JLC quite easily. This is kind of our thing, we are trying to build things for everyone to build and use, not just prototypes. If we post the board the files will be available just like all our CNC designs under the CERN license.

Just keep in mind there is not a lot of overhead on the 3.3V rail. It is designed to power the PicoBOB, not other things. Is there a schematic available for the pendant you want to use?

The pendant will need 5V supply as well, glad you asked. Hopefully VSYS would be suitable for that.

No schematic available but below is the manual

nvcnc.net/pdf/NVCNC_NVMPG_EN.pdf

I will just put the pins out to an SMD header on the bottom and so that you can solder stuff up to it. Our users have lots of USB options for pendants when they use LinuxCNC and we have an OSHW pendant that we're working on as well:

 

Work in progress, I decided to do the rip-up and I have added two headers which mate with our existing keypad pendant device that we use with FlexiHAL.  These two headers have the pins that you wanted (UART and some GPIO, plus 3.3V and 5V) so you should be able to make a small interface module to connect to any pendant or just fly wire things.

github.com/Expatria-Technologies/RT_Jog_Controller

 

Thanks! The jog controller is interesting. Is there details on the protocol used somewhere? Maybe a Remora module for it would be a better solution.