Crystal value for OSC0 that best fit UARTs baud rates

Rodrigo Aznar Mendes

Hi all,

The AM335X datasheet mention some options for the OSC0 Crystal (24, 25, 26MHz). This clock reference is also used to generate the internal clock base for the UARTs.

Question is: which crystal value best fits for the exact baud rates expected on the UARTs (for instance 9600, 115200)

Thanks a lot

Rodrigo

over 13 years ago

0 Rodrigo Aznar Mendes over 13 years ago

Prodigy 215 points

Hello,

I would put my question in other way:

In the manual the Table 19-6 presents the error values (%) for each Baud Rate, considering that a functional clock of 48MHz is the internal source for UART.

Is it possible to use any of the values proposed for the crystal (24, 25 or 26MHz) and have the same error values?

Thanks

Rodrigo

0 Rodrigo Aznar Mendes over 13 years ago in reply to Rodrigo Aznar Mendes

Prodigy 215 points

Hi all,

Could someone from TI post a comment on this issue? We need to define the final BOM of our design.

Thanks a lot

Rodrigo

0 JJD over 13 years ago in reply to Rodrigo Aznar Mendes

TI__Guru* 86540 points

Rodrigo, the functional clock for the UART will always be 48MHz, no matter what system clock frequency you choose. So the table you reference will apply for any of the supported OSC0 frequencies.

regards,

james

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Crystal value for OSC0 that best fit UARTs baud rates