Pflash completeness check

[charles_wangw]

Dear 

We use an S32K144 MCU and play to check if the code is completeness when power on every time. Now we calculate CRC of checksum and save the value at then end of Flash. And Read every byte of flash of all the setting address when power on. Compare the saved checksum and new calculated checksum. But it cost too much time. About 40ms now. 

Do we have an hardware method to get the same purpose to check if the Flash are the same as Programed(No damaged)  

Thanks you very much.

Charles

[lukaszadrapa]

Hi Charles,

I can see two options:

1. Use Secure boot function which checks the flash content.

https://www.nxp.com/webapp/Download?colCode=AN5401 

https://www.nxp.com/webapp/Download?colCode=AN5401SW 

See chapter "4.4 Secure Boot"

2. Another option is to use DMA and CRC module. DMA can feed the CRC on background, so you will not lose so much time.

Regards,

Lukas

[charles_wangw]

Hello Lukas

Thank you very much. Do we also have an example for DMA or CRC?

Thank you again.

Charles

[lukaszadrapa]

Hi Charles,

I wrote such example for MPC5748G:

Example MPC5748G CRC32 GHS614 

There's the same DMA module, so you can see how to configure the DMA. CRC module is very simple module, there shouldn't be a problem.

Then there's set of examples (including DMA) for S32K in this application note:

https://www.nxp.com/docs/en/application-note/AN5413.pdf 

The zip file is currently not available on the web, so I will attach it here.

Regards,

Lukas

[charles_wangw]

Hello Lukas

I find another example (Which is the same type MCU with mine):

https://community.nxp.com/docs/DOC-332957

But every time when I step run to :  

DMA->TCD[0].CSR &= 0xFFFFFFFF ^ DMA_TCD_CSR_DONE_MASK;  // Clear Channel Done flag

it will goes to  HardFault_Handler. DO you have good suggestion why it runs this fault?

Note: I copy the DMA related information from this example to my project. 

Thanks

Charles

[lukaszadrapa]

Hi Charles,

not sure what's going on. Do you have some simple project which could be shared? I can check it.

Regards,

Lukas

[charles_wangw]

Hello Lukas

How can I send you attachment?

Our project is too big. I can  send you the code I add from DMA in our project.

Thanks

Charles

[lukaszadrapa]

Hi,

attachment can be added directly to a post, just click on "Use advanced editor" on the right side of "Reply" window.

You can also double check used address and value when writing the TCD.CSR. It should be address 0x4000901C and the value depends on original value with cleared DONE bit. I can see in my debugger:

Or do you use memory protection unit? Are other writes to TCD working?

Regards,

Lukas

[charles_wangw]

Hello Lukas

Thanks. eDMA works my local now. I am trying to use CRC now. Still have two parts need your help.

1. CRC config error. After the first line config below, any code I put in the second line will go to HardFault_Handler. Very stange

CRC->CTRL = CRC_CTRL_TCRC(1)|CRC_CTRL_TOTR(3)|CRC_CTRL_TOT(3);

CRC->GPOLY = 0x04C11DB7;

CRC->CTRL = CRC_CTRL_TCRC(1) | CRC_CTRL_TOTR(3)|CRC_CTRL_TOT(3)|CRC_CTRL_WAS(1);

CRC->DATAu.DATA = 0xFFFFFFFF;

CRC->CTRL = CRC_CTRL_TCRC(1) | CRC_CTRL_TOTR(3)|CRC_CTRL_TOT(3)|CRC_CTRL_WAS(0);

2.  I want to calculate all the Pflash CRC. How Can I control the total bytes transfer from eDMA to CRC? Or no bytes limit for CRC?

3. By the way I also try to update the result CRC to Flash if not equal.  The most less bytes to update Pflash is 8bytes?

Thank you very much.

Charles

[lukaszadrapa]

Hi Charles,

1. Take a look at SW example in AN5413:

https://www.nxp.com/docs/en/application-note/AN5413.pdf 

I can see that the zip file associated with this application note is not available on the web now for some reasons, so I will attach it here. Have you enabled clocks to CRC module? This seems to be the reason. You can see that in the example.

2. There's no limit for CRC module.

3. Yes, that's due to ECC. Anytime you program a phrase (8 bytes), ECC is calculated for this phrase and it's stored together with the data to flash. This also means that we are not allowed to program phrase which is not fully erased - this would corrupt the ECC.

Regards,

Lukas

[charles_wangw]

Hello Lukas

Thanks, you are correct. I miss the clocks. And reconfig it base on the datasheet. CRC works.

They are all 16bits now. I am trying 32bits. But seems DMA config always not work.

DMA->TCD[0].ATTR = DMA_TCD_ATTR_SMOD(0) |               // Source address modulo feature is disabled

DMA_TCD_ATTR_SSIZE(2) |                // Source data transfer size: 1: 16-bit, 2=32-bit

DMA_TCD_ATTR_DMOD(0) |                // Destination address modulo feature: 0=disabled, x= x power of 2 buffer[DMOD=4->buffer of 16bytes]

DMA_TCD_ATTR_DSIZE(2);                // Destination data transfer size: 1: 16-bit, 2=32-bit

WHen I update above from 16bits to 32bits. It can not read out any data.

Regards

Charles

[lukaszadrapa]

Have you updated also NBYTES parameter? It was 2 in previous configuration, should be 4 now. Please give this a try.

Lukas

[charles_wangw]

Hello Lukas

Yes, DMA can read 4 bytes now. 

WHen I caculate CRC. It seems the value not match the result.

PCC_CRC->PCCn |= PCC_PCCn_MASK;
CRC->CTRL = CRC_CTRL_TCRC(1)|CRC_CTRL_TOTR(0)|CRC_CTRL_TOT(0);
CRC->GPOLY = 0x04C11DB7;
CRC->CTRL = CRC_CTRL_TCRC(1) | CRC_CTRL_TOTR(0)|CRC_CTRL_TOT(0)|CRC_CTRL_WAS(1);
CRC->DATAu.DATA = 0xFFFFFFFF;
CRC->CTRL = CRC_CTRL_TCRC(1) | CRC_CTRL_TOTR(0)|CRC_CTRL_TOT(0)|CRC_CTRL_WAS(0);
CRC->DATAu.DATA = 0x00260020;

u16DestBuffer1[15]=(CRC->DATAu.DATA);

And the result u16DestBuffer1[15]  =0x 60E11069

while the result from On-line CRC calculation and free library  and Vector hex view are all 0x26EAC586

I don't know why. Please help

Regards.

Charles.

[lukaszadrapa]

Hi Charles,

it depends on settings in CTRL register. I got the same result when used these settings:

Regards,

Lukas

[charles_wangw]

Hello Lukas

I come to this topic again.

It works perfect till now with EDMA and CRC module to calculate whole flash CRC32.

My new question S32K144 is 32-bits CPU. Our original method is read from flash bytes and bytes (with out EDMA). Which cost too much time. Why EDMA can so fast? It doesn't use same 32bits wire width?

Charles

[charles_wangw]

Hello Lukas

It works. Thank you very much.

Best Regards

Charles