Hi,

Do you use any external SDRAM or just the M3 own memory ?... If you do not have 
any extra RAM
I do not see how you can run HTTPS.. you need around 100-200K RAM to run HTTPS 
for one page.
The estimate is based that your page hase one or more JS files, one or more 
images, one or more
CSS files... in all you need 4-6 connections to load a single page and that 
needs lots of RAM.

Every SSL connection needs 16K for receive and 16K for transmit + some 
overhead. If you tweak
mbedTLS and use a smaller send buffer you may save on RAM but still need about 
20+K RAM for
a connection... multiply that by 4-6 that's a lot.

As for hardware acceleration... some M3 have DES, AES, SHA, CRC and RNG 
engines. This may help but
It is not related to big numbers, as far as I understand.

Have you been able to run the SSL server demo from mbedTLS ?... If not then I 
suggest first run the demo
And then work on your own code.

Good luck,
Noam.

From: lwip-users [mailto:lwip-users-bounces+noam=silrd....@nongnu.org] On 
Behalf Of antonio
Sent: Thursday, June 08, 2017 10:31 AM
To: lwip-users@nongnu.org
Subject: Re: [lwip-users] Building mbedtls using LWIP library :: Handshake 
takes too long

Hi all, I am trying to port mbedTLS to work with my embedded device. My problem 
is that the handshake procedure never completes, therefore, I am unable to have 
any HTTPS communication. Further debugging, I noticed that the math 
computations are taking too long (bignum.c). Is there a way to avoid such a 
mess ? I am using MC "arm-cortex-m3", which I believe can achieve fast 
computations. Any kind of optimizations etc is kindly welcome. /Antonio
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Handshake takes too 
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