Clarification on CRC32 Algorithm Differences (YTM32B1MD Series)

[tuanduong]

Dear Yuntu Support Team,

I hope you are doing well.
I am currently working with the YTM32B1MD microcontroller series and using the on‑chip CRC32 hardware module to verify firmware integrity. However, we have observed that the CRC32 result generated by the Yuntu hardware CRC engine does not match the CRC32 result produced by the IAR ielftool (CRC32/Ethernet configuration).
To ensure our firmware integrity workflow is correct, we would like to request official confirmation of the exact CRC32 parameters used by the Yuntu CRC hardware.
Specifically, could you please help confirm the following details?

1. CRC Polynomial

We currently understand the polynomial as:
X^32 + X^26 + X^23 + X^22 + X^16 + X^12 + X^11 + X^10 + X^8 + X^7 + X^5 + X^4 + X^2 + X + 1
which corresponds to 0x04C11DB7 (CRC‑Ethernet / IEEE 802.3).
Please confirm whether this is correct.

2. Input and Output Reflection

Does the Yuntu CRC module perform:

REFIN (bit reflection on input bytes)?
REFOUT (bit reflection on the final CRC value)?

3. Initial CRC Value (Init / Seed)

What is the default initial value used by the hardware?
(e.g., 0xFFFFFFFF, 0x00000000, or another value)

4. Final XOR Value

Does the hardware apply a final XOR (e.g., 0xFFFFFFFF) automatically, or should this be done in software?

5. Byte Ordering / Word Feeding

When feeding 32‑bit data into the CRC module:

Should bytes be provided in little‑endian order?
Does the hardware internally reverse byte order?

6. Any Known Differences Compared to Standard CRC‑Ethernet

Are there any Yuntu‑specific variations that may cause mismatch with tools such as IAR, Python, or standard CRC32 calculators?

Understanding these exact CRC parameters is important for us to:

• Align our bootloader and firmware integrity checks
• Ensure IAR post‑build CRC matches Yuntu HW CRC results
• Comply with integrity requirements in our production workflow

We would greatly appreciate your guidance or example code/configuration showing the correct CRC32 usage for YTM32B1MD.

IAR generated CRC32
ielftool --checksum=__CRC32:4,crc32:i,0xFFFFFFFF;0x00000000-0x000203FB
firmware.out firmware_crc.out

[Derrick]

Our hardware CRC32 may require a ByteSwap of uint32 values when passing arrays as arguments. The hardware CRC should be big-endian aligned.