Kinetis Microcontrollers中的主题 Re: K66 Flexbus, multiplexed and non multiplexed mode

K66 Flexbus, multiplexed and non multiplexed mode

tatalifaku — Tue, 22 Aug 2017 08:14:22 GMT

Hello,

I am new to flexbus usage and I don't understand how the K66 chooses between multiplexed and non multiplexed mode.

I am using a MK66FX1M0VMD18 and according to reference manual, it support both multiplexed and non multiplexed 32-bit address and 32-bit data busses. The little note "Some modes of operation (like 32-bit non-multiplexed address and data busses) require signals to actually be available on the pins of your specific device package" does not really help because I have not seen anywhere a list of the required pins for the non-multiplexed mode.

I tried to configure FB_CSCR0 with BLS=1, AA=1 and PS=0 (I also tried 1 and 2) but I seem to remains in multiplexed mode. FB_CSAR0=0x6000_0000, FB_CSMR0=0x0000_0001 => 64KB block @0x6000_0000. CSPMCR = 0x0222_2000.

I also tried FB_CSCR0 with BLS=1, AA=1, PS=1 (8 bits) with CSPMCR = 0x0200_0000 without any success.

Can someone give a working example or explanation of the minimal settings required to use non-multiplexed 32-bit address and 32-bit data busses ?

Thanks,

Re: K66 Flexbus, multiplexed and non multiplexed mode

Hui_Ma — Wed, 23 Aug 2017 05:30:19 GMT

Hi,

The Flexbus non-multiplexed mode or multiplexed mode based on chip pin resource.

The 32-bit data port non-multiplexed mode need use splitted address line, while MK66FX1M0VMD18 doesn't provide enough splitted Flexbus address pins, which missing FB_A[15:0].

So, MK66FX1M0VMD18 doesn't support 32-bit data port non-multiplexed mode.

Customer can only use Flexbus with 32-bit data port multiplexed mode.

There is an application note AN4393 about Flexbus function, please check here for detailed info.

Thank you for the attention.

Have a great day,
Ma Hui

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Re: K66 Flexbus, multiplexed and non multiplexed mode

tatalifaku — Wed, 23 Aug 2017 07:31:52 GMT

Ok, now, I understand why I'm stuck in multiplexed mode.

In fact, AN4393 is a bit a reason of my misunderstanding. It tried to create something like the LCD example but in non multiplexed mode.

Thanks.