[TriEmbed] Freescale K20 doc (re: McHck)

[Pete Soper]

If like me you've stumbled through the main, clear as mud K20 family 
datasheet while wondering what the real differences are between the 
umpteen flavors of Freescale's K20/21/22 ARM chips, here is the doc made 
for us (juicy bit starts at page 6):

http://cache.freescale.com/files/32bit/doc/prod_brief/K20PB.pdf?&Parent_nodeId=&Parent_pageType=

The McHck BOM includes a very low end K20: MK20DX32VLF5 (details 
starting on page 10).

I'm hoping there's no gotcha with using larger (in terms of memory) 
versions. Here are the specs and Mouser  prices for 3 flavors. For $1.06 
more than the standard chip I'd like to have virtual acres of memory and 
start using a real operating system (e.g. FreeRTOS) while not having to 
worry much about constraints.

                        FLASH  FLEXNVM  EEPROM/FLEXRAM  SRAM (all in 
kilobytes)

MK20DX32VLF5    $3.72   32      32 2              8
MK20DX64VLF5     4.15    64      32      2     16
MK20DX128VLF5    4.78   128      32      2             16

-Pete