[Cryptech Tech] never do in software what can be done in hardware

[Benedikt Stockebrand]

Hi Fredrik and list,

Fredrik Thulin <fredrik at thulin.net> writes:

> [MSP430 counters not being double buffered]
> AFAICT, the msp430 reads 16 bits at a time from memory. If I read a single 
> byte, it appears to read a word and discard half of it.

hmm, in that case the datasheet should give an explanation how to do
this correctly.

>> That sounds pretty good; looks like we're getting close to what's
>> actually possible on the MCU side.
>
> Probably, for the ~20 MHz range. I'm slowly working on a new prototype with an 
> 84 MHz  STM32 CPU instead. Currently using the STM32F401 Nucleo evaluation 
> board. I'm quite curious to see what can be done with one of those, but I 
> don't have that much time available at the moment. Will keep you posted.

I have somewhat similar plans (and the same problem with regard to
time).  One of the ideas I have it so use a Raspberry Pi, or Beagle Bone
Black, or whatever with GPIO pins and see how that works out.

>From what I get from the Oscilloscope I really guess that'll get quite
another performance boost.

> No worries. I was ordering stuff anyways and got the inexpensive Sparkfun 
> Pocket AVR Programmer (https://www.sparkfun.com/products/9825).

OK; I don't know that one in particular, but you can really save 2/3 of
the money if you don't buy the original Atmel stuff.

>> Right; I run the timer at clock speed and every sampling iteration takes
>> three clock cycles.  Since I only use the least significant bit anyway
>> this works out just fine.
>
> You're in luck the sampling takes an odd number of cycles ;)

Well, it's not so much luck but checking data sheets, assembly code
output and eventually testing things:-)


Cheers,

    Benedikt

-- 
Benedikt Stockebrand,                   Stepladder IT Training+Consulting
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