Lpc2000

I am missing something.

You say that there is a problem when MAM is disabled, but then work-
around #2 says to disable the MAM!

Please clarify.


--- In lpc2000@yahoogroups.com, "philips_apps" <philips_apps@y...> 
wrote:
> 
> We recently discovered a bug in the MAM block and it affects the  
> LPC213x family, description of which is provided below. The Errata 
> sheet (for this family) has been updated and is on its way for 
> publishing. 
> 
> --------------------------------------------------------------------
> MAM.1		
> Incorrect read of data from SRAM while code is running from Flash 
and 
> MAM is disabled
> 
> Introduction:
> The Memory Accelerator Module (MAM) provides nearly zero-wait state 
> execution from the on-chip flash at higher frequencies.
> 
> Problem:
> While code is running from the on-chip Flash, if a data fetch is 
> initiated from SRAM, the data read might be corrupted.
> 
> Work-around:		
> There are two possible workarounds: 
> 1. Fully enable the MAM (MAMCR=0x2) and use the appropriate MAMTIM 
> value. Enabling the MAM will reduce current consumption (since the 
> MAM buffers four ARM or eight Thumb instructions with each Flash 
> fetch) and also provide nearly zero-wait state execution from Flash 
> above 20MHz.
> 2. Disable MAM (MAMCR=0x0) and set MAMTIM=0x1. If the MAM is 
> disabled, this will lead to increased current consumption as each 
> fetch will result in a read of the Flash memory. In addition, it 
> limits execution out of Flash to 20MHz. This approach would however 
> provide deterministic behaviour.
> 
> The first workaround is the recommended solution as the application 
> can achieve considerable power savings and also does not put any 
> restriction on the operating frequency.	
> 
> --------------------------------------------------------------------
-
> 
> 
> Best Regards,
> Philips Apps