FlexBus configuration question K20 - Mqx 4.0

[cavebiker]

I have a simple question (I think) before we spin some boards I want to be sure about this.

The problem: I need to configure FlexBus to non-multiplex mode. My question is about assigning the address and data lines.

This is what I want to do:

Assign AD0 to AD7 to be the 8 data lines.

and

Assign A16-A29 to be the 14 address lines.

Will this work?

Thanks a ton in advance.

Cheers,

Tom

[weblar]

Hi Tom,

I routed my FlexBus slightly differently on a K60 device but I guess the end result should be the same.

I've got an SRAM device with 20 address pins and 16 data. I routed FB_AD[0-15] and FB_A[16-19] to the ADDR[0-19] signals and routed FB_AD[16-31] to my DATA[0-15] pins.

I'm hoping that I've got this configuration correct.

Kev

[cavebiker]

Hey Kev,

Did this work for you? I never got Flexbus working correctly in this configuration. My hardware team is telling me Freescale told them that it is wired wrong, so I just created the bus with I/O :smileyplain:. It works but we are re-spinning the board so we can use Flexbus.

Cheers,

[weblar]

Hi Tom,

Sorry its taken so long to reply, I don't log on to this forum as often as I should.

Yeah, my FlexBus is working perfectly - I've got an LCD and SRAM hooked up to the FB using different chip selects and both devices seem to work without issue. What was your exact pin mapping?

Cheers,

Kev

[cavebiker]

That should work if I am reading the manual correctly. Good luck.

Cheers,

Tom

[cavebiker · Accepted solution]

Yes, it looks like the boards are wired correctly based on what the K20 manual says:

Module signal name Description I/O

FB_AD[29:16] Address Bus When FlexBus is used in a nonmultiplexed configuration, this is the

address bus.

FB_AD[31:0] When FlexBus is used in a nonmultiplexed configuration, this is the data bus, FB_D.