MB9BF368N VCC & main clock relation

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gulec_2585086
Level 1
Level 1
5 questions asked First reply posted First question asked

Hi Cypress,

   

Show that on datasheet : VCC < 4.5V, main clock using 4M~20MHz and VCC ≥ 4.5V, main clock using 4M~48MHz

   

What the VCC & main clock relation and principle?  Does the clock rising/ falling time? 

   

 

   

- G.L

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HolgerW_56
Employee
Employee
25 solutions authored 10 sign-ins 5 sign-ins

Hi,
the internal clock oscilator/circuitry depends on the supply voltage.

   

For 5V (>4.5V) application it works up to 48MHz, while for 3V3 (<4.5V) the clock circuitry runs up to 20Mhz.

   

Anyhow, we suggest to use a 'low-frequency' crystal, e.g. 4MHz and using the internal PLL. That gives better EMI result for your system.

   

Regards, Holger

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HolgerW_56
Employee
Employee
25 solutions authored 10 sign-ins 5 sign-ins

Hi,
the internal clock oscilator/circuitry depends on the supply voltage.

   

For 5V (>4.5V) application it works up to 48MHz, while for 3V3 (<4.5V) the clock circuitry runs up to 20Mhz.

   

Anyhow, we suggest to use a 'low-frequency' crystal, e.g. 4MHz and using the internal PLL. That gives better EMI result for your system.

   

Regards, Holger

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gulec_2585086
Level 1
Level 1
5 questions asked First reply posted First question asked

Hi Holger,

   

I want to know what should using P61/UHCONX pin control UDP (D+) high/low?

   

And what is the UDP (D+) high and low status?

   

 

   

-G.L

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HolgerW_56
Employee
Employee
25 solutions authored 10 sign-ins 5 sign-ins

Hi, please see the 32 Bit Microcontroller FM4 Family Peripheral Manual Communication Macro Part.pdf, CHAPTER 3-1: USB Device (USB Function)

   

http://www.cypress.com/file/222976/download

   

Here a schematic extract form our starter kit

   

   

Does this answer your question?

   

Rgds, Holger

   

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gulec_2585086
Level 1
Level 1
5 questions asked First reply posted First question asked

Hi Holger,

   

I understand the USB D+ pull-high which is Full Speed. Does this MCU on USB programming mode when USB D+ no level(UHCONX pull-up)?

   

- G.L

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