[sdiy] Digital delay memory

Eric Brombaugh ebrombaugh1 at cox.net
Wed Apr 27 20:37:15 CEST 2016

On 04/27/2016 11:29 AM, Jay Schwichtenberg wrote:
> We see a lot of little ARM boards come out like the Teensy/Arduino for
> example. I'd like to see something like that with a higher end ARM chip on a
> bigger board with USB and bootloader, external fast ram and more pins broken
> out. That to me would be a good basic platform for doing a whole lot of
> stuff. Main problem for hobbyists like us is most ARM chips that have an
> external memory interface are in BGA (Ball Grid Array) packages. These would
> require some form or reflow soldering. Some people have used toaster ovens
> and hot plates to do that but it sounds pretty tricky for the average
> person. Also the boards would probably have to be more than 2 layers with
> buried and blind vias.

Check these parts out:


The 144-pin LQFP shown supports external SDRAM chips (think 64MB for 
about $5). Has a nice I2S-compatible serial audio port that hooks to a 
wide variety of codecs. Single-precision / single cycle floating point 
math at 180MHz. Lots of on-chip flash and QSPI for off-chip XIP if 
needed. Under $10 in qty, easy to DIY if you can handle SMT soldering - 
I do those by hand all the time.


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