19.6.2 CRC Control
| Name: | CRCCTRL |
| Offset: | 0x02 |
| Reset: | 0x0000 |
| Property: | PAC Write-Protection, Enable-Protected |
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| CRCSRC[5:0] | |||||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | |||
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | |||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| CRCPOLY[1:0] | CRCBEATSIZE[1:0] | ||||||||
| Access | R/W | R/W | R/W | R/W | |||||
| Reset | 0 | 0 | 0 | 0 | |||||
Bits 13:8 – CRCSRC[5:0] CRC Input Source
This bit field selects the input source for generating the CRC, as shown in the table below. The selected source is locked until either the CRC generation is completed or the CRC module is disabled. This means the CRCSRC cannot be modified while the CRC operation is ongoing. The lock is signaled by the CRCBUSY status bit. CRC generation complete is generated and signaled from the selected source when used with the DMA channel.
| Value | Name | Description |
|---|---|---|
| 0x00 | NOACT | No action |
| 0x01 | IO | I/O interface |
| 0x02-0x1F | — | Reserved |
| 0x20 | CHN0 | DMA Channel 0 |
| 0x21 | CHN1 | DMA Channel 1 |
| Other | — | Reserved |
Bits 3:2 – CRCPOLY[1:0] CRC Polynomial Type
This bit field controls the polynomial type used to calculate the CRC checksum.
| Value | Name | Description |
|---|---|---|
| 0x0 | CRC16 | CRC-16 (CRC-CCITT) |
| 0x1 | CRC32 | CRC32 (IEEE® 802.3) |
| Other | — | Reserved |
Bits 1:0 – CRCBEATSIZE[1:0] CRC Beat Size
This bit field controls the size of the data transfer for each bus access when the CRC is used with the I/O interface.
| Value | Name | Description |
|---|---|---|
| 0x0 | BYTE | 8-bit bus transfer |
| 0x1 | HWORD | 16-bit bus transfer |
| 0x2 | WORD | 32-bit bus transfer |
| Other | — | Reserved |