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Discussion Groups | LPC900 | about UART performance
Find help, specifications and source code for the LPC900. The LPC900 challenges Microchip and AVR based on the worlds most popular 8-bit architecture the 80C51. With a 2-clock core the LPC900 series is a high performance, very flexible and low cost 8-bit microcontroller family. Designers using or interested in these devices are encouraged to share their know-how and ask questions.
about UART performance - yen0yuki - Oct 31 2:12:00 2005
hello,
I want to know about UART performance.
(1)In case of LPC900 series Microcontrollers use UART,
How much will permissible range of error margin?
(2)The baud rate is seleced from RC oscillator.
Can I set Hi-speed?
Please teach someone.
Regards,
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
I want to know about UART performance.
(1)In case of LPC900 series Microcontrollers use UART,
How much will permissible range of error margin?
(2)The baud rate is seleced from RC oscillator.
Can I set Hi-speed?
Please teach someone.
Regards,
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
Re: about UART performance - philips_apps - Oct 31 5:13:00 2005
Hello,
the permissible Error margin combined over the transmition of a byte
including start and stopbit has to be less than half a bit.
Half a bit is 50%, let's assume both receiver and transmitter are
off by 2.5%, one too fast, the other too slow, in this case it would
just no longer work.
If both are better than 2.5% it usally works. Now, if you
communicate with a PC, that usually has a very exact baudrate of
e.g. 115200. You can be off by 4% and it will still work.
The LPC900 devices are specified with 1% at room temperature and
better than 2.5% over the whole temperature range.
The max UART transmition rate is the CPU clock rate divided by 16.
If the CPU runs at 7.373MHz like most of the internal RC oscillators
of the LPC900 family do, your max. baudrate is 460.8 Kbaud.
Philips Apps Team
--- In lpc900_users@lpc9..., "yen0yuki" <tadayuki@r...>
wrote:
>
> hello,
>
> I want to know about UART performance.
>
> (1)In case of LPC900 series Microcontrollers use UART,
> How much will permissible range of error margin?
>
> (2)The baud rate is seleced from RC oscillator.
> Can I set Hi-speed?
>
> Please teach someone.
>
> Regards,
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
the permissible Error margin combined over the transmition of a byte
including start and stopbit has to be less than half a bit.
Half a bit is 50%, let's assume both receiver and transmitter are
off by 2.5%, one too fast, the other too slow, in this case it would
just no longer work.
If both are better than 2.5% it usally works. Now, if you
communicate with a PC, that usually has a very exact baudrate of
e.g. 115200. You can be off by 4% and it will still work.
The LPC900 devices are specified with 1% at room temperature and
better than 2.5% over the whole temperature range.
The max UART transmition rate is the CPU clock rate divided by 16.
If the CPU runs at 7.373MHz like most of the internal RC oscillators
of the LPC900 family do, your max. baudrate is 460.8 Kbaud.
Philips Apps Team
--- In lpc900_users@lpc9..., "yen0yuki" <tadayuki@r...>
wrote:
>
> hello,
>
> I want to know about UART performance.
>
> (1)In case of LPC900 series Microcontrollers use UART,
> How much will permissible range of error margin?
>
> (2)The baud rate is seleced from RC oscillator.
> Can I set Hi-speed?
>
> Please teach someone.
>
> Regards,
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )