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Is the TWR-K20D72M supposed to work with the TWR-SER?  and MK20DX256VLL7 msd mfs generic host?

Question asked by Robert Hana on Aug 11, 2014
Latest reply on Aug 12, 2014 by Kan_Li

I am having trouble getting the TWR-K20D72M working with the example "MK20DX256VLL7_msd_mfs_generic_host"  from the USB 4.1.1 stack.


First: There don't appear to be any debug messages coming from the DB-9 RS-232 connector on the TWR-SER (looking at the schematics they appear to be connected to UART1 on the K20 from the DB-9, through the Tower-ELEV, and onto the TWR-K20D72M) I added a printf() in the main loop in main.c and there isn't anything coming from the RS-232 either. I did add "#define MCU_MK20D7" to derivative.h


The debug messages should appear according to sci_kinetis.h "there is an #ifdef MCU_MK20D7 for UART1, lines 60 - 92."


Second. The program is running according to the debugger. I can step through the code, it goes to check the USB for events. However the board isn't detecting any USB stick when plugged in to J3 when left to run without interruption (the project appears to have msd drivers, I would expect a datastick to light up at least.)


Third. My jumper settings are correct on the TWR-SER and TWR-K20D72M


-Plugging in a USB stick has no effect.

-The RS-232 does not issue debug statements


I have tried USB as both standalone

-My jumper settings on TWR-K20D72M: J16 1&2, 5&6


...and with the TWR-SER

- TWR-SER board, J16 on position 1-2(VB_HOST)

- TWR-SER board, J10 on default position 1-2(USB host)

- on TWR-K20D72M: J16 6&8


I know these devices were designed for each other, what am I doing wrong here, it must be a simple mistake? Is there something else I have to change in derivative.h or sci_kinetis.h?





Update: I have measured J3 and on the TWR-K20D72M and it doesn't look like it is getting 5 Volts there (Voltage between pnis 1 and 5)