Electrical design guidelines

[lucholtkamp]

Can anybody tell me where I can find electrical design guidelines for K10 72MHz.

I have trouble to find any documentation on this subject. For instance:

• I will not use RTC or VBAT, so what to do with the VBAT pin? connect it to VDD? And what to do with the XTAL32 pins? leave it open? ground it?
• In the datasheet it sais that one should use 'proper PCB layout' for the clock crystal circuit. But I can't find any documentation what a 'proper PCB layout looks like'
• What to do with the USB pins if I do not use USB? ground it? leave it open?
• What about other pins I do not use, just leave them open?
• What is the recommended filter circuit for the VDDA/VSSA/VREFH/VREFL circuit?
• Examples for FlexBus and EzPort

It would be great to have a few application notes with 'minimal configurations' showing how to use the chip from an electrical viewpoint.

Regards,

Luc

[Paul_Tian]

Hi, Luc

One more thing, different power pins which should be connected together, please seires a magnetic bead between them.

Hope my reply can help you.

Best Regards

Paul

[Paul_Tian · Accepted solution]

Hi, Luc

• I will not use RTC or VBAT, so what to do with the VBAT pin? connect it to VDD? And what to do with the XTAL32 pins? leave it open? ground it?

     Answer: Agree with Erik, leave open

• In the datasheet it sais that one should use 'proper PCB layout' for the clock crystal circuit. But I can't find any documentation what a 'proper PCB layout looks like'

     Answer: I think you can reference chapter 4.5 in document "Kinetis quick start guide ", you can find it from link http://cache.freescale.com/files/32bit/doc/quick_ref_guide/KQRUG.pdf?fsrch=1&sr=1

• What to do with the USB pins if I do not use USB? ground it? leave it open?

     Answer: Answer: Agree with Erik, leave open

• What about other pins I do not use, just leave them open?

      Answer: Agree with Erik, leave open

• What is the recommended filter circuit for the VDDA/VSSA/VREFH/VREFL circuit?

     Answer: I think you can reference chapter 4.5 in document "Kinetis quick start guide ", you can find it from link http://cache.freescale.com/files/32bit/doc/quick_ref_guide/KQRUG.pdf?fsrch=1&sr=1

• Examples for FlexBus and EzPort

     Would you please help to tell me that you need HW connection reference or sample code?

     Hope my reply can help you.

     Best Regards

     Paul

[erikmalund]

• I will not use RTC or VBAT, so what to do with the VBAT pin? connect it to VDD? And what to do with the XTAL32 pins? leave it open? ground it?
• leave open
• In the datasheet it sais that one should use 'proper PCB layout' for the clock crystal circuit. But I can't find any documentation what a 'proper PCB layout looks like'
• no more than 5mm traces to the crystal or the burden caps
• What to do with the USB pins if I do not use USB? ground it? leave it open?
• leave open
• What about other pins I do not use, just leave them open?
• leave open
• What is the recommended filter circuit for the VDDA/VSSA/VREFH/VREFL circuit?
• decoupling caps with no more than 5mm traces

Erik