Lpc2000

--- In lpc2000@yahoogroups.com, "karlstiller" <karls@...> wrote:
>
> Hi guys,
> 
> Another new member, and another problem.  I appreciate any help, and 
> I hope to be able to return the favor in the future.
> 
> I am in the final stages of a project that uses a LPC2106.  Things 
> work perfectly as it is, but we have recently discovered that we are 
> getting low performance issues as we are running without the MAM and 
> PLL.
> 
> I am currently working on trying to add in the MAM and PLL, but I 
> have run into problems.  Basically what I have found is the following:
> 
> 1. When running either the MAM or the PLL, interrupts from UART1 TX 
> stop occurring
> 2. When running both the MAM and the PLL, the processor doesn't seem 
> to run properly, or digital outputs no longer happen.
> 
> I am testing, using a program that does the following:
> 1. Clears Pin
> 2. Enables PLL (and or) MAM
> 3. Sets Pin
> 4. Calls function
> 5. Clears Pin.
> 
> The program was made to see the performance increases using the PLL 
> and MAM.  When running the PLL or the MAM the program works fine.  
> However, when running both the PLL and MAM, the last clear pin does 
> not occur.  I'm unsure what's happening, as when I step through the 
> program step by step using J-Tag, it works as expected!
> 
> When adding the PLL or the MAM into the existing project, 
> communication on UART1 stops working.  The first byte is sent 
> correctly, but the rest of the string (sent using the interrupt 
> generated from UART1 TX) isn't sent.
> 
> I have read the Philips datasheet, and the guide from Hitex (The 
> Insider's Guide To The Philips ARM7-Based Microcontrollers) and 
> haven't found anything relating to the MAM or PLL and its effects on 
> interrupts.
> 
> Any ideas?
> 
> Karl
>

But, you haven't told us the important stuff: what crystal frequency,
what PLL setup (for a 14.7456 MHz crystal, PLLCFG=0x23 works), what
MAM setup (MAMCR=0x02 and MAMTIM=0x04 works) and what VPBDIV (0x01 works).

These values are from James Lynch's excellent tutorial. Rev 3 is here:
http://www.olimex.com/dev/pdf/ARM%20Cross%20Development%20with%20Eclipse%20version%203.pdf

There is a complete distribution of the entire tool chain somewhere. 
Search the archives here to see who hosts it.

Richard