AM335x allowed UART baudrates

Vasili Galka

Hi,

I'm a little confused by the TRM. From "19.3.8. Protocol formatting" (rev I):
"UART16x ≤460Kbits/s if MDR3[1] is set"
"UART 13x mode (≥460.8 Kbits/s) if MDR3[1] is not set"

Does that mean that the 16x mode is forbidden to use for higher baud-rates? Or the documentation is just unclear?
For example, I would like to use x16 mode with divider of 1 which gives me 3Mbaud rate.

Best,
Vasili

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

Hi Vasili,

The available baud rates for UART mode are shown in Table 19-25.

0 Vasili Galka over 12 years ago in reply to Biser Gatchev-XID

Expert 2690 points

Hi Biser,

I've seen the table. But my question is if these are the only supported baud-rates and if custom baud-rates can be used?

Best,
Vasili

0 Biser Gatchev-XID over 12 years ago in reply to Vasili Galka

TI__Guru**** 393215 points

Vasili,

This is a standard UART. Any baud rate that can be derived from the 48MHz clock and 13x or 16x oversampling can be used. Of course not all baud rates will have an acceptable error margin.

0 Vasili Galka over 12 years ago in reply to Biser Gatchev-XID

Expert 2690 points

Great, thank you!
I had doubt because from the TRM (quoted above) could be (misleadingly) concluded that only 13x can be used for high baud-rates.

0 Biser Gatchev-XID over 12 years ago in reply to Vasili Galka

TI__Guru**** 393215 points

No, the table simply lists the standard baud rates.

0 Vasili Galka over 12 years ago in reply to Biser Gatchev-XID

Expert 2690 points

I was talking about this sentence: "UART16x ≤460Kbits/s" :-)

0 Biser Gatchev-XID over 12 years ago in reply to Vasili Galka

TI__Guru**** 393215 points

I think this is just dragged in from some other document. In Table 19-6 there is a 3 000 000 bps setting with 16x oversampling.

0 Vasili Galka over 12 years ago in reply to Biser Gatchev-XID

Expert 2690 points

Oh, right...
I looked at Table 19-25 which is similar but does not contain 3 000 000 ...

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AM335x allowed UART baudrates