Module Operation
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SPNU563A–March 2018
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Cyclic Redundancy Check (CRC) Controller Module
18.2.13 Peripheral Bus Interface
CRC is a Peripheral slave module. The register interface is similar to other peripheral modules. CRC
supports following features:
• Different sizes of burst operation.
• Aligned and unaligned accesses.
• Abort is generated for any illegal address accesses.
18.3 Example
This section illustrates several of the ways in which the CRC Controller can be utilized to perform CRC.
18.3.1 Example: Auto Mode Using Time Based Event Triggering
A large memory area with 2Mbyte (256k doubleword) is to be checked in the background of CPU. CRC is
to be performed every 1K byte (128 doubleword). Therefore there should be 2048 pre-recorded CRC
values. For illustration purpose, we map channel 1 CRC Value Register to DMA channel 1 and channel 1
PSA Signature Register to DMA channel 2. Assume all DMA transfers are carried out in 64-bit transfer
size.
18.3.1.1 DMA Setup
• Set up DMA channel 1 with the starting address from which the pre-determined CRC values are
stored. Set up the destination address to the memory mapped channel 1 CRC Value Register. Put the
source address at post increment addressing mode and put the destination address at constant
addressing mode. Use hardware DMA request for channel 1 to trigger a frame transfer.
• Set up DMA channel 2 with the source address from which the contents of memory to be verified. Set
up the destination address to the memory mapped channel 1 PSA Signature Register. Program the
element transfer count to 128 and the frame transfer count to 2048. Put the source address at post
increment addressing mode and put the destination address at constant address mode. Use hardware
DMA request for channel 2 to trigger an entire block transfer.
18.3.1.2 Timer Setup
The timer can be any general purpose timer which is capable of generating a time-based DMA request.
• Set up timer to generate DMA request associated with DMA channel 2. For example, an OS can set up
the timer to generate a DMA request every 10ms.
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