Lpc2000

What is the maximum baud rate that the uart of these devices can support? 
I'm interested in driving an RS485 link at up to 1 mbps.

- Chris

Hi Chris,

	From my testing of RS422/485 and a LPC2106 running at 14.7456MHz
external clock, 460.8K baud and maybe, just maybe 921.6K.
You must also have 120 ohm resistors on the master and the last slave unit
as close to the RS422/485 chip as possible.

Charles

-----Original Message-----
From: Chris Graham [mailto:chris_e_gr@...] 
Sent: Sunday, January 09, 2005 8:40 PM
To: lpc2000@yahoogroups.com
Subject: [lpc2000] Max Baud Rate of LPCxxxx UART?



What is the maximum baud rate that the uart of these devices can support? 
I'm interested in driving an RS485 link at up to 1 mbps.

- Chris 



 
Yahoo! Groups Links

Hi Chris,

don't know the specifics (penalties) of the RS422/485 but the serial
interface can go to a maximum of CPU clock divided by 16. So, running
at 14.7456 it could go to 921.6 kbaud. Make sure that the divider for
the peripherals (VPBDIV) is changed to 1, default after reset is
divide by 4. If you go to 1 Mbit, you should have a 16 MHz clock or a
multiple thereof. 

Cheers, Bob


--- In lpc2000@yahoogroups.com, "Charles R. Grenz"
<charles.grenz@s...> wrote:
> Hi Chris,
> 
> 	From my testing of RS422/485 and a LPC2106 running at 14.7456MHz
> external clock, 460.8K baud and maybe, just maybe 921.6K.
> You must also have 120 ohm resistors on the master and the last
slave unit
> as close to the RS422/485 chip as possible.
> 
> Charles
> 
> -----Original Message-----
> From: Chris Graham [mailto:chris_e_gr@y...] 
> Sent: Sunday, January 09, 2005 8:40 PM
> To: lpc2000@yahoogroups.com
> Subject: [lpc2000] Max Baud Rate of LPCxxxx UART?
> 
> 
> 
> What is the maximum baud rate that the uart of these devices can
support? 

> I'm interested in driving an RS485 link at up to 1 mbps.
> 
> - Chris 
> 
> 
> 
>  
> Yahoo! Groups Links

Is the external clock a clock or a XTAL? (If it's an
XTAL you should be able to multiply it up by 4 with
the PLL to get a faster peripheral clock (<= 60MHZ)
and get 4 times the baud rate).

Jane

 --- lpc2100_fan <lpc2100_fan@...> wrote: 

---------------------------------

Hi Chris,

don't know the specifics (penalties) of the RS422/485
but the serial
interface can go to a maximum of CPU clock divided by
16. So, running
at 14.7456 it could go to 921.6 kbaud. Make sure that
the divider for
the peripherals (VPBDIV) is changed to 1, default
after reset is
divide by 4. If you go to 1 Mbit, you should have a 16
MHz clock or a
multiple thereof. 

Cheers, Bob


--- In lpc2000@yahoogroups.com, "Charles R. Grenz"
<charles.grenz@s...> wrote:
> Hi Chris,
> 
>       From my testing of RS422/485 and a LPC2106
running at 14.7456MHz
> external clock, 460.8K baud and maybe, just maybe
921.6K.
> You must also have 120 ohm resistors on the master
and the last
slave unit
> as close to the RS422/485 chip as possible.
> 
> Charles
> 
> -----Original Message-----
> From: Chris Graham [mailto:chris_e_gr@y...] 
> Sent: Sunday, January 09, 2005 8:40 PM
> To: lpc2000@yahoogroups.com
> Subject: [lpc2000] Max Baud Rate of LPCxxxx UART?
> 
> 
> 
> What is the maximum baud rate that the uart of these
devices can
support? 
> I'm interested in driving an RS485 link at up to 1
mbps.
> 
> - Chris 
> 
> 
> 
>  
> Yahoo! Groups Links





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