MSPM0G3519: Trying to run CRCP against a standard IEEE 802.3 polynomial

Hi CY,

It is a hardware accelerator.

Chris Yorkey said:

• Does CRCP stream 32b data byte-by-byte through the CRC engine or the whole 32b value is used?
• Any hints or suggestion on how to configure CRCP to get this right or maybe some pseudo code explaining how CRCP CRC engine works?

It doesn't matter how it really works in low level, we can treat it as an input-output model.

For the how to implement in software code, you can refer to the SDK demo project, which also includes the DMA methods for this.

https://dev.ti.com/tirex/explore/node?node=A__ALAN0bj6VmKQrgGhjKb.Eg__MSPM0-SDK__a3PaaoK__LATEST 

It is a CRC16 demo, while it is simple to migrated to CRC32.

Several configurations need be taken care of:

1.CRC-32 setting:

2. SEEK value (initialization value)

I am not sure what's IEEE 802.3 is, while I tested it with JAMCRC, with the input of string {'1','2','3','4','5','6','7','8'}

And the output is "0x651F2550", which is the correct result of the CRC input string.

B.R.

Sal

Hi Eugene,

Eugene K said:

The "check CRC" in the tables below is for ASCII values ’1’ ’2’ ’3’ ’4’ ’5’ ’6’ ’7’ ’8’ ’9’ corresponding to values 31h 32h 33h 34h
35h 36h 37h 38h 39h is fed through the specified algorithm byte-by-byte.

I tested the input of ‘1-8’, due to CL asked this in the thread:

Chris Yorkey said:

 Our customer is trying to run CRCP against a standard IEEE 802.3 '0x04C11DB7' polynomial and test string {'1','2','3','4','5','6','7','8'}. That should generate 0xE3C97CBC CRC. But can’t really get it to work.

I believe this is correct value:

So, one conclusion from your side is correct, the final XOR operation is not executed in the hardware side.

I just used the example project, and modify it to CRC-32, the sysconfig file:

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#include "ti_msp_dl_config.h"

#define CRCP_NUM_OF_WORDS (8)
#define CRCP_EXPECTED_RESULT (0x651F2550)
uint8_t gData8[CRCP_NUM_OF_WORDS] = {'1', '2', '3', '4', '5', '6', '7', '8'};

const uint32_t gCrcpSeed            = CRCP_SEED;
volatile bool gCheckCRCP;

int main(void)
{
    volatile uint32_t crcpChecksum;
    __attribute__((unused)) volatile bool crcpChecksumMatch;

    SYSCFG_DL_init();

    /* Configure DMA source, destination and size */
    DL_DMA_setSrcAddr(DMA, DMA_CH0_CHAN_ID, (uint32_t) &gData8[0]);
    DL_DMA_setDestAddr(DMA, DMA_CH0_CHAN_ID, DL_CRCP_getCRCINAddr(CRCP0));
    DL_DMA_setTransferSize(
        DMA, DMA_CH0_CHAN_ID, sizeof(gData8) / sizeof(uint8_t));
    DL_DMA_enableChannel(DMA, DMA_CH0_CHAN_ID);

    /*
     * Confirm DMA channel is enabled before issuing a SW trigger of the DMA
     * channel
     */
    while (false == DL_DMA_isChannelEnabled(DMA, DMA_CH0_CHAN_ID)) {
        __BKPT(0);
    }

    /* Configure device exception handling */
    DL_SYSCTL_disableSleepOnExit();
    NVIC_EnableIRQ(DMA_INT_IRQn);
    gCheckCRCP = false;

    /* Trigger DMA via SW request */
    DL_DMA_startTransfer(DMA, DMA_CH0_CHAN_ID);

    /* Wait in SLEEP mode until DMA interrupt is triggered */
    while (false == gCheckCRCP) {
        __WFE();
    }

    /* Check CRCP checksum */
    crcpChecksum = DL_CRCP_getResult32(CRCP0);

    if (CRCP_EXPECTED_RESULT == crcpChecksum) {
        crcpChecksumMatch = true;
        DL_GPIO_clearPins(GPIO_LEDS_PORT, GPIO_LEDS_USER_LED_1_PIN);
    } else {
        crcpChecksumMatch = false;
    }

    __BKPT(0);

    while (1) {
        __WFI();
    }
}

void DMA_IRQHandler(void)
{
    switch (DL_DMA_getPendingInterrupt(DMA)) {
        case DL_DMA_EVENT_IIDX_DMACH0:
            gCheckCRCP = true;
            break;
        default:
            break;
    }
}

Then, you can modify it without sysconfig, all the code the example project is attached.

Eugene K said:

• Would result change when data is fed into CRCP using 32 bit quantities (LE): 0x31323334 and 0x3536373839?
• What would change if the 32 bit quantities are in BE 0x34333231 and 0x3938373635?

You can take a try based on the project. I think the #2 will output the same result, and #3 will not.

B.R.

Sal