I'm working on a radio receiver project based on using a Uniden BC125AT, which will be controlled by an external microcontroller.

The original plan was to tap into the BC125AT keypad to issue keypresses etc, an ugly solution, but it works.

But the BC125AT has a USB port for programming and control, and of course this is a USB-serial interface. When I pulled the BC125AT apart I was hoping to find an FTDI so I could tap into the serial and and use our microcontroller to issue commands. Unfortunately they're using a Renesas V850ES/JG3-L 32-bit micro with on-chip USB controller: http://www.farnell.com/datasheets/1581873.pdf

So now I'm left wondering if there's anything I can realistically do to interface with it? Of course I could use a single board computer... but that's overkill just to achieve comms and I think we'd just go back to hacking the keypad. I really just want to see if I've missed any options?


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    \$\begingroup\$ Have you considered using a microcontroller with USB OTG support? It could then act as a host for your BC125AT. Many of the Freescale and ST ARM Cortex microcontrollers have a USB peripheral with this capability and aren't too expensive. \$\endgroup\$ Jul 13, 2017 at 3:32
  • \$\begingroup\$ I honestly don't know what you want to achieve. The BC125T manual says "USB drivers and programming software are available..." and they provide a web site for that. What is it that you cannot do via their drivers and some PC software? (Note the protocol doc, as well: info.uniden.com/twiki/pub/UnidenMan4/BC125AT/… ) \$\endgroup\$
    – jonk
    Jul 13, 2017 at 3:32
  • \$\begingroup\$ @jonk As far as I have understood some circuit containing a microcontroller shall change the settings of the BC125T - without using a PC. I doubt that the PC software will run on a microcontroller. \$\endgroup\$ Jul 13, 2017 at 4:26
  • \$\begingroup\$ @MartinRosenau True enough. But I'm not sure what the goal actually is. And until that's expressed clearly enough, it's hard to know if the right tree is being barked up. I just felt I didn't understand enough to decide independently and the OP didn't make me feel solid enough about their own choice, either. So there it is. \$\endgroup\$
    – jonk
    Jul 13, 2017 at 5:11
  • \$\begingroup\$ The days of USB being limited to computers has long padded. You can get dollar microcontroller that do usb host built in \$\endgroup\$
    – Passerby
    Jul 13, 2017 at 6:02

2 Answers 2


What you are looking for is USB Host, sometimes called USB OTG.
Not all microcontrollers can do this, but you should be able to find some.

That is only the hardware side though, you will also need software. For example, what device classes does the radio use? (it can have multiple) Does it enumerate as virtual serial port, or does it use custom drivers?

If you know this, you can get onto host software. Mbed has a library.

  • \$\begingroup\$ Thanks. I suspect the software side is going to be the most difficult. The radio does appear as a virtual serial port, which will hopefully make things easier! \$\endgroup\$ Jul 14, 2017 at 22:22


  1. use a USB OTG Controller


  1. use FT232RL (For USB Device) or FT311D (For USB Host OTG)

FT311D host can be implemented with simple UART or I2C protocol and very easy to implement.


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