lpcware

LPC43S20 - using AES 128 with code size larger than internal SRAM

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by rsbogdan on Fri Nov 13 14:21:12 MST 2015
We currently use the LPC4337 and load code from the external flash using the 256-bit decryption in firmware.

To move to a Flashless part for cost savings, we will need to use the the LPC43S30 AES 128-bit engine version to keep the Ethernet interface. (LPC43S20 seems to have better availability, but we can't use it)

The LPC43S30 has only 256kB SRAM internal. Our  overall code +  data memory size exceeds this, but I might assume that the AES engine can manage partial code blocks in SRAM (cache-style) ?
Is it true that we can have an internal SRAM size smaller than our executable and we would just have wait states for code misses while (it's) loading alternate 128-bit blocks ?

I can't find this in the AES functional description.

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