help with usb A to type c and MCU

[dorimon1000]

hi everyone! im designing a board which will include RT1170 family MCU and im willing to place a Type C connector for ease of connectivity.
the thing is im really confused on how should i connect it if i want to burn image to the MCU with that USB port..

from my understanding , the PC is the host which will be connected to the type C via a cable TYPE A to TYPE C plugs.

the thing is , i dont know if simply leaving the CC pins will do the job, (and of course shorting the  D+ pair and the D- pair.
i want to be able simply give power to the USB1 BUS and to be able to upload the image. meaning the MCU will be the device, the pc will be the HOST.

how do i achieve that?

thanks!!

[ataradov]

For it to be a device you need to properly connect D+/D- (not shorting them). And you need to connect 5.1 kOhm resistors to the ground from the CCx pins (one per pin).

You also need to check if there is some bootloader that can talk over USB on that device. And if not, you will have to find or make one. And if there is one, you need to read its exact requirements. Bootloader may put additional requirements on the crystal frequency, for example.

[dorimon1000]

D+ D- arent shorted , usb C has 2 pins D+ and 2 pins D- .. so the D- are shorted together and the D+ pair are together  (thats incase the type c will be plugged in other direction)

what i dont understand is why put 5.1k resistors to gnd on the ccX pins , since USB A doesnt even have these pins , only the type C part has.. and my mcu has nothing to do with the CCx pins..

[ataradov]

Well, yes, you need to connect D+ and D- pairs.

You don't need CCx pins if you don't plan on using USB-C to USB-C cables. But if you actually want to be compliant to the standard and work in all cases, then you need them.

[dorimon1000]

but will that allow me connect host to my MCU? i dont want to connect a device such as a keyboard , just to be able to program the MCU from PC

[ataradov]

Yes it will as long as there is a USB bootloader running. It won't just work on its own if there is no corresponding software running. You need to check if there is a bootloader in the ROM in that device. If not, then you will have to use the regular programming interface once to place the bootloader. After that bootloader will be able to program the flash over USB.