basic questions for testing tango 9k board

[jschoch]

Hello, I had a few basic questions.

1. if using a 5 axis mach bob it seems the inputs from the tango9k are unbuffered. Does this mean it can be driven by 3.3v logic with no problems?
2. is the connection with an esp32: linuxcnc(udp)-> udp esp32 w5500 (esp32) -> udp to spi (esp32) -> spi (tango9k) -> spi bob ?
3. what are the expansion and extra input pins used for, are they unused on your board?
4. is the uln2803 used just to buffer 12-24v?, what drove the selection of that chip? i don't have one so i'm wondering if i need it or if i can replace it with something like a ULN2003

I'm not at all familiar with the bob board but they were cheap so I bought one.

I'm planning on milling a board so I likely can't use the routing you have in your kicad files. What would be the easiest way to get a test setup with a tango 9k in your opinion? I'm thinking of driving it with a pi 4 but i'm not married to that idea, and i have some esp32's (c6, s3, 32u) and some external W5500 modules.

regarding the 5v or 3.3v i have some level shifters and I also have some shift registers that can buffer the outputs. I wonder if you have seen how fluidNC is using 74AHCT595 and i2s for output expansion?

[multigcs]

Hi,

1. Yes, but only tested with the china BOB
2. You can use it for anything you want, controlled by the .json config
3. i used it for port-expansion via Shift-Register
4. for level-shifting and for more current if you need to drive LED's or Optocoupler, ULN2003 is only for '7bit', the uln2803 have 8

The BOB adapterboard is single sided, so you can also milling it.
If you use RPI4, you can connect the TangNano9K via SPI without anything else between, the UDP-Bridge is optional.

At the begining, i have some trouble with I2C on the FPGA (verilog), so i used shift registers for the expansion,
for I2C expansion, i have to add a new plugin first. And the shift registers are mush faster then I2C.