Lpc2000

I just posted a simple Win32 cmd line tool to calculate the optimum register 
settings for a LPC214x UART peripheral.
I am not aware if all the LPC2k UART peripherals are the same or not.  If so 
great.  I was working against the LPC2148 user manual.

It seems the equation in the user manual to calculate the baud rate is 
incorrect.

It should be:
Baudrate = 
(PCLK/(16*(256*PRE_SCALE_MSB+PRE_SCALE_LSB)))*(MulVl/(MulVal+DivAddVal))

opposed to:
Baudrate = 
(PCLK/(16*(16*PRE_SCALE_MSB+PRE_SCALE_LSB)))*(MulVl/(MulVal+DivAddVal))

I replicated the user manual example baud table using my software with 
modified equation.

Minor typo in the user manual:  The percent error value for the optimized 
56000 baud is incorrect, it should read 0.1600 opposed to 0.0160.

I hope you find it useful.

If can be found in:  http://groups.yahoo.com/group/lpc2000/files/Tools/


Regards,
Joel Winarske
Systems Architect
Independent Electronics, Inc.
V 707.320.4271
M 408.203.2770
F 408.516.5978
www.indyelectronics.com

--- In lpc2000@yahoogroups.com, "Joel Winarske" <joelw@i...> wrote:
>
> I just posted a simple Win32 cmd line tool to calculate the 
optimum register 
> settings for a LPC214x UART peripheral.
> I am not aware if all the LPC2k UART peripherals are the same or 
not.  If so 
> great.  I was working against the LPC2148 user manual.
> 
> It seems the equation in the user manual to calculate the baud 
rate is 
> incorrect.
> 
> It should be:
> Baudrate = 
> (PCLK/(16*(256*PRE_SCALE_MSB+PRE_SCALE_LSB)))*(MulVl/
(MulVal+DivAddVal))
> 
> opposed to:
> Baudrate = 
> (PCLK/(16*(16*PRE_SCALE_MSB+PRE_SCALE_LSB)))*(MulVl/
(MulVal+DivAddVal))
> 
> I replicated the user manual example baud table using my software 
with 
> modified equation.
> 
> Minor typo in the user manual:  The percent error value for the 
optimized 
> 56000 baud is incorrect, it should read 0.1600 opposed to 0.0160.
> 
> I hope you find it useful.
> 
> If can be found in:  
http://groups.yahoo.com/group/lpc2000/files/Tools/
> 
> 
> Regards,
> Joel Winarske
> Systems Architect
> Independent Electronics, Inc.
> V 707.320.4271
> M 408.203.2770
> F 408.516.5978
> www.indyelectronics.com
>
Hi, 
 There is already similar tool in file section in file LPCUST.zip.
 Is your utility different in calculations ? 
 Radim.

I changed the name of this to "LPC2000 UART Fractional Divider Calculator".

http://groups.yahoo.com/group/lpc2000/files/Tools/lpc2fdcalc.exe

As far as I have determined, only the LPC214x series UART implements a 
Fractional Divider.  This is a very nice feature, more parts should 
implemented this.  RS-485 hardware support (tx enable) would be a plus too.


-Joel

> Hi,
> There is already similar tool in file section in file LPCUST.zip.
> Is your utility different in calculations ?

Yes, mine is solely for calculating the optimal values for a UART that 
implements a fractional divider.  Which currently addresses the LPC214x 
series.

-Joel

Radim,

the major difference is that you don't need to use a 14.756 MHz any
more to get to a 115200 (or for that matter any standard baudrate). 
The fractional baudrate generator is new to the LPC214x and for a
reason. To run the USB, you need a value for the clock like 12 MHz or
16 MHz. This does not compute very well with 115200 serial baudrate if
you don't have a fractional baudrate generator.
I hope there will be such a BR-generator also on the CAN chips some
time soon as they face the same problem.

Bob

--- In lpc2000@yahoogroups.com, "radim100" <radim100@y...> wrote:

>
> --- In lpc2000@yahoogroups.com, "Joel Winarske" <joelw@i...> wrote:
> >
> > I just posted a simple Win32 cmd line tool to calculate the 
> optimum register 
> > settings for a LPC214x UART peripheral.
> > I am not aware if all the LPC2k UART peripherals are the same or 
> not.  If so 
> > great.  I was working against the LPC2148 user manual.
> > 
> > It seems the equation in the user manual to calculate the baud 
> rate is 
> > incorrect.
> > 
> > It should be:
> > Baudrate = 
> > (PCLK/(16*(256*PRE_SCALE_MSB+PRE_SCALE_LSB)))*(MulVl/
> (MulVal+DivAddVal))
> > 
> > opposed to:
> > Baudrate = 
> > (PCLK/(16*(16*PRE_SCALE_MSB+PRE_SCALE_LSB)))*(MulVl/
> (MulVal+DivAddVal))
> > 
> > I replicated the user manual example baud table using my software 
> with 
> > modified equation.
> > 
> > Minor typo in the user manual:  The percent error value for the 
> optimized 
> > 56000 baud is incorrect, it should read 0.1600 opposed to 0.0160.
> > 
> > I hope you find it useful.
> > 
> > If can be found in:  
> http://groups.yahoo.com/group/lpc2000/files/Tools/
> > 
> > 
> > Regards,
> > Joel Winarske
> > Systems Architect
> > Independent Electronics, Inc.
> > V 707.320.4271
> > M 408.203.2770
> > F 408.516.5978
> > www.indyelectronics.com
> >
> Hi, 
>  There is already similar tool in file section in file LPCUST.zip.
>  Is your utility different in calculations ? 
>  Radim.
>