C8051F960-B-GM Datasheet, PDF (171/492 Pages) Silicon Laboratories – Ultra Low Power 128K, LCD MCU Family

C8051F96x
13.6. Using CRC1 with SFR Access
The steps to perform a CRC using SFR access with the CRC1 module is as follow:
1. If desired, set the SEED bit in the CRC1CN SFR to seed with 0xFFFF.
2. Clear the CRC module by setting the CLR bit in the CRC1CN SFR.
3. Clear the SEED bit, if set previously in step 1.
4. Write the polynomial to CRC1POLH:L.
5. Write all data bytes to CRC1IN.
6. If desired, invert and/or flip the final results using the INV and FLIP bits.
7. Read the final CRC results from CRC1OUTH:L.
8. Clear the INV and/or FLIP bits, if set previously in step 6.
Note that all of the CRC1 SFRs are on SFR page 0x2.
13.7. Using the CRC1 module with the DMA
The steps to computing a CRC using the DMA are as follows.
1. If desired, set the SEED bit in CRC1CN to seed with 0xFFFF.
2. Clear the CRC module by setting the CLR bit in CRC1CN SFR.
3. Clear the SEED bit, if set previously in step 1.
4. Write the polynomial to CRC1POLH:L.
5. Configure the DMA for the CRC operation:
a. Disable the desired DMA channel by clearing the corresponding bit in DMA0EN.
b. Select the desired DMA channel by writing to DMA0SEL.
c. Configure the selected DMA channel to use the CRC1IN peripheral request by writing 0x2 to
DMA0NCF.
d. Enable the DMA interrupt on the selected channel by setting bit 7 of DMA0NCF.
e. Write 0 to DMA0NMD to disable wrapping.
f. Write the address of the first byte of CRC data to DMA0NBAH:L.
g. Write the size of the CRC data in bytes to DMA0NSZH:L.
h. Clear the address offset SFRs DMA0A0H:L.
i. Enable the interrupt on the desired channel by setting the corresponding bit in DMA0INT.
j. Enable the desired channel by setting the corresponding bit in DMA0EN.
k. Enable DMA interrupts by setting bit 5 of EIE2.
6. Set the DMA mode bit (bit 3) in the CRC1CN SFR to initiate the CRC operation.
7. Wait on the DMA interrupt.
8. If desired, invert and/or flip the final results using the INV and FLIP bits.
9. Read the final results from CRC1OUTH:L.
10. Clear the INV and/or FLIP bits, if set previously in step 8.
Rev. 1.0
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