Missing FlexBus pins in MK53DX256CMD10

[msmrecza]

Hello,

I planned to use MK53DX256CMD10 and FlexBus communication with 32 AD lines (i.e. FB_AD[31:0]). The reference manual of the microcontroller describes everything as if the communication using 32 lines was possible. However, for some reason, the pinout is missing the signals FB_AD[23:21]. The package is 144-pin and pins PB6-PB8 are available (normally the FB lines should be at ALT5). Could you tell me if there is a mistake in the reference manual or if I am missing something?

Thank you in advance,

M.

[RaRo]

Hello @msmrecza,

You can find the available signals to use for the FlexBus for the MK53DX256CMD10 in the User Manual, Datasheet and ConfigTools Pins.

I would recommend you to try the following Application Note: Using FlexBus Interface for Kinetis Microcontrollers, and verify if this works for your needs. Even though they are not using the K53, perhaps you might find it useful considering that it shows a couple of examples that don't use the FB_AD[23:21] signals.

Best regards, Raul.

[msmrecza]

Hello @RaRo  and thank you for your answer.

In my case I am constrained by the application and I must use all 32 lines. Does it mean it is certain that the MK53DX256CMD10 doesn't have the 3 mentioned signals? I find it inconsistent with the rest of the documentation and some of your documents describing FlexBus in 144-pin packages though... Do you know if there is any particular reason for that?

Thanks,

M.