Problem with USB enumeration in MSP430F5635

Jenitta Rex

Intellectual 660 points

I get problems in USB enumeration .

The connection state is CONNECTED_NO_ENUM.

when i step into the code , i can see that USB pll is not locked .

what can be the problem ?

USBOORIFG , USBLOSIFG and USBOOLIFG are set in USBPLLIR register .

Thanks

Jenitta

over 13 years ago

0 Jenitta Rex over 13 years ago

Intellectual 660 points

The external crystal used is 16MHz for XT2. Should I program the USBPLLDivB reg ? If so , when and in what sequence ?

Thanks !

0 Jenitta Rex over 13 years ago in reply to Jenitta Rex

Intellectual 660 points

I configured the USBPLLDIVB register to the value according to my input crystal .

Now the PLL is settled and working ..

0 Long Cao over 13 years ago in reply to Jenitta Rex

Prodigy 80 points

Jenitta Rex said:

I configured the USBPLLDIVB register to the value according to my input crystal .

Now the PLL is settled and working ..

Thank Jenitta, your suggestion solved the problem for me.
The exact way to find what/where to fix it is carefully written here:http://e2e.ti.com/support/microcontrollers/msp43016-bit_ultra-low_power_mcus/f/166/t/124221.aspx

In short, open msp430fxxxx.h and find those USBPLL_SETCLK defininitions, choose the setting best fit your xt2 frequency(I use 25MHz, so I choose 25_6) and copy it to this line:#define USB_XT_FREQ USBPLL_SETCLK_4_0

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Problem with USB enumeration in MSP430F5635