Kinetis K82F ROM bootloader using OpenSDA COM port

[guenter_loettrich]

Hi,

which default LPUART is used for communicatioin with the ROM bootloader in K82F?

I'm using FRDM-K82F but I could not establish communication when using blhost. I've wired PTC3 and PTC4 to R36 and R32 on the board like recommended in the K80 FAQ.

The MCU's flash on the board is in erased state therefore the ROM bootloader should start up automatically but it doesn't work.

Or am I missing something?

br

Guenter

[guenter_loettrich]

Hi Fan,

I'll try with USB2SER the comming days. My original thought was to use the virtual COM port of OpenSDA. So I removed R32 and R36 from the FRDM-K82 and soldered wires from J24 (PTC3 and PTC4). No success so far.

[ramboyang]

Usually, it is not recommended to use the virtual COM port of OpenSDA to talk to ROM bootloader. Based on our test result, the virtual COM port is unstable sometimes compared with USB2SER.

[Carlos_Mendoza]

Hi Guenter,

To enter bootloader mode you need to assert the NMI pin at reset, the NMI button on the FRDM-K82F is the SW2.

Hope it helps!

Best Regards,

Carlos Mendoza

[guenter_loettrich]

Hi Carlos,

thanks. I forgot to mention that I followed the instructions pressing SW2 while powering-on the board respective push and releae the Reset button while SW2 is pressed.

Unfortunately this doesn't work.

Also another board shows the same behaviour.

My second question is which default UART is used by the ROM bootloader if the flash of K82 is erased. According Table 8-1 there are several instances for bootloader operation through LPUART.

Manual says something about a default configuration but I couldn't figure out so far what the default config is.

br

Guenter

[Carlos_Mendoza]

Hi Guenter,

By default, when the device enters the bootloader mode it initializes the 3 LPUART modules (along with the other supported peripherals) and checks if a ping packet is received in any of them, so you should be able to communicate trough any instance of the UART. How are you connecting the board to your computer? If you are using a USB2SER please make sure that the COM number send in the command corresponds to the USB2SER COM port.

Hope it helps!

Best Regards,

Carlos Mendoza