PCB - USB communication - K64

[flauberttagu]

Hello everyone,

We are looking for tuto or PDF (drawing) which will help us to know how to design our PCB in order to make the USB communication and data transfert with the NXP K64. We already have a gerber created but we do not know if our PCB allows the USB communication regarding what we did.

Can you help us?

Best regards.

[nxf51211]

Hi,

Please check the document presented in the following link: Kinetis Hardware Design Tip & Tricks.

If you go to pages 36 to 37 you will find recommendations for the use of USB on Kinetis.

I hope this information can help you.

Ricardo Delsordo

[flauberttagu]

Hi,

Thank you for your answer.

We did more research and we find out that we need to use the RX and TX connection to establish our SDA.

We already have flash memory which is connected in UART_CTS_b and UART_RST_b. Because our PCB was made by someone else, we do not know if this pin can be used for SDA.

And if it is the case, do we need to rout USB to the same pin or else?

Regards.

[nxf51211]

Hi,

I would like to ask you if you refer to SDA as the Serial Debugger or something else. This is because the K64 Evaluation Board communicates with OPENSDA (this is with a K20) through SPI and not UART.

I'm not sure if I understood correctly your idea, please correct me if I'm wrong with something.

Ricardo Delsordo.

[flauberttagu]

The SDA we are talking about is the Serial data. If we are not wrong, it is use for data transfert in and out of the MCU or additional flash memory.

The SPI is already used by another module. So now we can only use UART for pin connection.

The idea is a computer send data into the flash memory through USB connection, this data is used regarding the features we developed and send back to the computer.

Regards.

[nxf51211]

Hi,

Thank you so much for the clarification about the meaning of SDA. To establish SDA you indeed need to use RX and TX pins; CTS/RTS are only used for data flow control (you cannot transfer data with these).

Also, I'd like to know what type of flash memory are you using, and what is the protocol you're implementing for communicating the flash memory with the PC.

Regards,

Ricardo Delsordo.

[flauberttagu]

Hi,

Thank you for your aswer. If the CTS/RTS cannot be use for then the flash memory must be connected to other pins. Which pin do we have to use for the memory flash.

We are using a standard flash memory key from microchip. Regarding your question about the protocol of communication, we wish to know first of all if we can fix the hardware before taking the developping the software.

To aswer to your question, we do not use any communication protocol with the PC right now.

Regards.

[flauberttagu]

Ricardo Delsordo

Hi,

After looking closely to our product's schematics, I find out that for the flash memory we are using the UART_TX (PTA14) and URAT_RX (PTA15).

Our question must we put the connections pin connection of the USB in order to receive and send data with a PC.

Regards.

[nxf51211]

Hi,

If I understood your question correctly, then indeed you need to add the USB connections in order to receive and transmit data with the PC. Regarding your flash memory, please make sure that the one you're using does communicate through UART.

Please correct me if I'm wrong with something.

Best regards,

Ricardo Delsordo

[flauberttagu]

Hi Ricardo,

You understood our issues.

Thank you for your answer. We will connect USB to RX/TX to make sure the communication works.

Regards.