Asked

Rock Pi X Uart Or EZB Uart?

I's setting up a Rock Pi X running Win 10 and ARC to be an onboard SBC to control my robot. Currently It's controlling 3 EZB v4's and 1 IoTiny. I'm using most Uart connections on the V4 EZB's (port and digital pins) for my Sabertooth/Kangaroo motor controllers. I'm going to have to replace two of the EZB V4's with new ones. I was considering replacing them with a cheaper Arduino and flash it to turn it into an EZB but need Uart ports.

I have a couple questions: 1- What device is recommended that I can flash to make it an EZB that will give me two Uart ports each? (or at least one) I looked at each in the compatible hardware list for ARC and can't find one that offers a Uart. Unless I completely missed it.  2- The Rock Pi X offers two Uart ports on it's General purpose input-output (GPIO) connector.  Uart0 - Pin 9 is Ground, Pin 11 is UART0_TX and pin 13 is UART0_RX Uart2 - Pin 6 is Ground, Pin 8 is UART0_TX and pin 10 is UART0_RX Can I use these Uarts on the Rock Pi X with ARC for my Sabertooth/Kangaroo motor controllers ? If so how would I code the Board Index and Port in a script so ARC knows how to use the Rock Pi X Uarts? I know how to code the Data. Here is one example of one command I'd send to move a motor through an EZB Uart port to the Sabertooth:

uartWrite(0, 0, "1, p420 s200", 0x0d)

Thanks!!


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#1  

It appears the Kangaroo Sabertooth robot skill accepts UART or COM port connectivity.

User-inserted image

As for supported EZB hardware, it seems the census over here is that the only hardware supporting two or more UART will be too large for your form factor. And it is suggested to use USB to UART TTL devices instead. If you're low on USB ports, USB hubs can be purchased for a low cost.

#2   — Edited

Quote:

only hardware supporting two or more UART will be too large for your form factor.
Form factor? Are you saying that only one Uart on devices like Arduino is available? I did some research and I did find that all Arduino's have at least one Uart. Other Uarts are available through software emulation.

I'm thinking when a supported Arduino is flashed to be a EZB then the Arduino software that emulates the other Uarts is gone.

However, a V4 EZB has three Uart ports. One actual physical port and two others that are in the digital pins (can't remember the pin numbers right now). *Are these Uarts in the digital pins software emulated? *When I flash a supported Arduino to make it an EZB will I get Digital pins that I can use as TX RX Uart ports like on a V4 EZB?

As far as the Sabertooth Skill, I don't use it. I code everything. However maybe if I install the skill I'll get a hint of what is available.

Maybe I'm just going to have do this the old fashion way to test and do this by trial and error.. Thanks for you help.

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Synthiam
#3  

Software serial on arduino should be avoided. It’s very unreliable. Having one hardware uart is fine but doesn’t solve your questions. Because a usb to ttl adapter is so much cheaper and smaller. Way better than having a bunch of arduinos laying around in your robot.

for talking to uart, in JavaScript you use the UART class group: https://synthiam.com/Support/javascript-api/UART/hardwareUartAvailable

For talking to the pc com port, you use the COM class group: https://synthiam.com/Support/javascript-api/COM/available

#4  

Thanks DJ for pointing the way. I'm looking forward to learning all this and making it happen.

#5   — Edited

I'm a little confused on which USB to Uart TTL adaptor I should get. It looks like there are different types and use different voltages and do different things. I see some that use 3.3V and others that use 5V. I'm not sure this even matters.

When I run serial connection from an EZB Uart port to my Kangaroo that's commanding a Sabertooth I only need 3 wires (RX, TX, and a ground) and no voltage wire. The Kangaroo is powered from the Sabertooth. Will this 5V adaptor cable do the trick? I don't think I'd even use the power wire.

DTECH FTDI USB to UART TTL Serial 5V Adapter Cable 4 Wire End with FT232 Chip TX RX Signal for Windows 10 8 7 XP Vista (6ft, Black)