LPC MicrocontrollersのトピックRe: DMA with AES

DMA with AES

Jgeorge — Wed, 11 Aug 2021 20:22:22 GMT

Hi,

I am trying to Run AES using DMA.

I tried for last three days, but could not proceed further.

How I did?

1.I too sample code of DMA Memory to Memory from SDK

2.Added the AES header and Driver file in it.

3.Changed the AES configuration accordingly w.r.t DMA.

4.Then compiled and execute but code is stuck in while loop.

Please can anyone tell is this correct way of doing?

I read there are some trigger and input source for DMA request but couldn't find any example how to do it.

Can anyone share the pseudo code?

Re: DMA with AES

Alice_Yang — Thu, 12 Aug 2021 03:59:21 GMT

Hello Jgeorge,

Could you please show more information about your application.

The trigger Source of DMA ?

And do you use AES module of LPC55 or just software AES?

Alice

Re: DMA with AES

Jgeorge — Thu, 12 Aug 2021 04:13:31 GMT

No I haven't used trigger source but yes I read about it in UM ,can you please tell me any reference in demo code for trigger source or do I have to create my own.

yes I am using AES module of LPC55s69.I am using software key for AES.

Re: DMA with AES

Alice_Yang — Fri, 13 Aug 2021 04:02:03 GMT

Hello Jgeorge,

Please refer to "Configure the DMA as follows: ..." in UM to config DMA,

and the SDK demo with DAM, for example "usart_dma_transfer".

Alice

Re: DMA with AES

Jgeorge — Sat, 14 Aug 2021 16:34:17 GMT

Hi Alice_Yang,

Yes thanks for the information.

I have started exploring UART DMA code ,it's understandable now.

According to that only I am configuring for AES.

Sure I will share my complete code once I configure all the registers by tomorrow EOD.

Please see to it and looking forward for your feedback

Re: DMA with AES

Jgeorge — Mon, 16 Aug 2021 05:57:17 GMT

Hi Alice_Yang,

Sure,Please see the code i have done.You can also run the code at your side.Waiting for your reply.

Re: DMA with AES

Alice_Yang — Tue, 17 Aug 2021 07:47:16 GMT

Hello Jgeorge,

So what's your problem now? I think you can debug with breakpoint or step by step first confirm the detail

issue.

Alice

Re: DMA with AES

Jgeorge — Tue, 17 Aug 2021 11:21:00 GMT

Hi Alice_Yang,

Thanks for your code suggestion.

The code which i shared is not complete.

I have completed the code now and could debug with breakpoint step by step also.

The DMA transfer is working fine but the encrypted data from the output/DIGEST register is coming incorrect.

I am having doubt in giving the user key that is userkey should be loaded after the DMA transfer or before transfer?

I am doing before DMA transfer.

please suggest if there is any other way for getting output/DIGEST register.

Note:I am just a beginner !

Re: DMA with AES

Alice_Yang — Thu, 19 Aug 2021 08:00:30 GMT

Hello Jgeorge,

Yes, giving user key before DMA transfer is no problem.

It seems your code disable the use key and other AES encrypt related code.

Recommend first development base on hashcypt demo under SDK, change it to your request, and confirm the AES work well , the DIGEST data is right. then add DMA request on it.

Alice

Re: DMA with AES

Jgeorge — Thu, 19 Aug 2021 13:42:55 GMT

Hi Alice_Yang

Sure.Thanks for your suggestion

Regards,

Jacob