I have and audio application for which I want to be able to read and write a lot of data at the same time. So what's a lot of data? Well I want to use an Audio codec which will take 24bit samples at a rate of up to 96k samples per second. I want to 'record' up to 5 minutes of audio in stereo. So 24bits * 5 * 60 * 96000 *2 bits of stored data. (24bits is sample size, 5*60*96000 is 5 minutes sampling at 96,000 sps and 2 for stereo)
Now the codec will fire out a stream of data on an I2S connection. Since I want to record and play at the same time I'll need two I2S channels and somewhere to store the data. Since the data should survive a power down I'll have to be persistent memory, so EEPROM or FLASH. Given the memory size I assume it'll have to be FLASH, which will get very complicated as you'll have to wipe a page of Flash before re-write. Might be easier with twice as much Memory as you had spec'd above and write to one Flash chip and read from the other.
So now here's going to be the hard part, I'm small scale so want to be able to solder the Processor. Another hard part is that NXP documentation doesn't mention how you have to connect up the bare minimum connections to get a PCB working. It's not in the data sheet and there don't seem to be Application notes for that. So how do you find that out? I started a support chat with NXP and got told to ask on the forum! You have to find out connection data from the community? At the time I was at the time at the http://cache.freescale.com/files/microcontrollers/doc/data_sheet/K20P144M120SF3.pdf datasheet, but given that response I kinda left it, looking else where. I'm still looking and decided I'd ask the forum.
I should say that I was looking at a processor on farnell which pointed to that datasheet, above, but the datasheet suggested that it didn't document the footprint which was on farnell. So even if you find a chip on a supplier you struggle to find a datasheet and any connection information in it. I'm obviously missing something.
I guess all that connection and layout stuff only matters if you can make the chip store that amount of data.