Communication between FRDM-K66F and FPGA

[weijfh]

Dear all,

I trying to transfer data from microcontroller(FRDM-K66F) to FPGA(kc705) by uart.

I successfully transmitted data from FRDM-K66F to pc by uart and successfully received data from pc to KC705 by uart. However, I failed to transfer data from FRDM-K66FF to KC705.(Both FRDM-K66F and KC705 are 9600 baud rate, 8-bit data, 1 stop bit)

Can anybody give some advice?

Thanks,
Wei-Chieh

[Masmiseim]

This is a long chain of adapters. There could be a lot of possible fault location.

I guess you have connected KC705 directly to the PC via a mini-b cable which is working as you said?

Have you used the same adapters as shown in the picture to connect the K64 to the PC? Do you used the same USB-to-TTL-Adapter without the Type-A-to-mini-b Adapter?

If this is the case, the Type-A-to-mini-b is only new Adapter in the chain of adapters? Are you Shure that this adapter is working?

[Masmiseim]

Have you crossed Rx and Tx between K66 and KC705?

[weijfh]

Hi Masmiseim,

     Thank you for your reply.I have tried to swap Tx and Rx by exchanging the white line(D1) and brown line(D0). However, I still failed to receive data from K66. 

[Masmiseim]

Hello weijfh,

one more thing I noticed. The KC705 Board is a USB-Device with a virtual Serial-Port, correct? The USB-to-TTL adapter is also a USB-Device, connecting both together is not working. You need at least one USB-Master or OTG device.

Regards

[weijfh]

Hi Masmiseim,

Thank you for quick reply.
1.) I tested the adapter by connecting it with USB-to-USB adapter to PC, and it works well.
2.) Yes, the KC705 is a USB-Device with a virtual Serial-Port. Does it mean that I can't transfer
data from K66F to KC705?

Thanks,
Wei-Chieh

[Masmiseim]

Hello weijfh,

No, you can not transfer Data from two USB-Devices. You need a host in between. You could use for example a raspberry pie or a PC. Connect the two USB-Interfaces to it and run some code which bridges the two serial interfaces.

Alternatively, you can grab the RX and TX signals from the KC705 Board before the Silicon Labs USB to UART bridge and connect it directly to the K64 on TTL level.

regards

[weijfh]

Hi Masmiseim,

Thank you so much!

Thanks,
Wei-Chieh