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datasheet.md

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Datasheet

Overview

The crc IP is a fully parameterised soft IP recording the SoC architecture and ASIC backend informations. The IP features an APB4 slave interface, fully compliant with the AMBA APB Protocol Specification v2.0.

Feature

  • Max 32-bit CRC code calculation
  • Multiple CRC polynomials support
    • CRC8 - 0x07
    • CRC16 - 0x1021
    • CRC16 - 0x8005
    • CRC32 - 0x04c11db7
  • Input byte reverse support
  • Output bit reverse support
  • Programmable init data register and ouput XOR data register
  • Internal LFSR technique implementation
  • 1~4 APB4 clock cycle calculation peroid
  • Static synchronous design
  • Full synthesizable

Interface

port name type description
apb4 interface apb4 slave interface

Register

name offset length description
CTRL 0x0 4 control register
INIT 0x4 4 init value register
XORV 0x8 4 xor value register
DATA 0xC 4 data register
STAT 0x10 4 state register

Control Register

bit access description
[31:7] none reserved
[6:5] RW SIZE
[4:3] RW MODE
[2:2] RW REVOUT
[1:1] RW REVIN
[0:0] RW EN

reset value: 0x0000_0000

  • SIZE: the size of input data

    • 2'b00: 8 bits
    • 2'b01: 16 bits
    • 2'b10: 24 bits
    • 2'b11: 32 bits

  • MODE: the CRC polynomials mode

    • 2'b00: CRC8 (poly: 0x07)
    • 2'b01: CRC16 (poly: 0x1021)
    • 2'b10: CRC16 (poly: 0x8005)
    • 2'b11: CRC32 (poly: 0x04c11db7)

  • REVOUT: bit reverse of CRC output value

    • 1'b0: disable
    • 1'b1: enable

  • REVIN: byte reverse of CRC input value

    • 1'b0: disable
    • 1'b1: enable

  • EN: the enable signal of CRC core

    • 1'b0: disable
    • 1'b1: enable

Init Value Reigster

bit access description
[31:0] RW INIT

reset value: 0x0000_0000

  • INIT: the init value of CRC result

XOR Value Reigster

bit access description
[31:0] RW XORV

reset value: 0x0000_0000

  • XORV: the xor value of CRC result

Data Reigster

bit access description
[31:0] RW DATA

reset value: 0x0000_0000

  • DATA: the input or result value of CRC
    • write this regiser will start a new CRC calculation
    • read this register will get CRC result

State Reigster

bit access description
[31:1] none reserved
[0:0] RO DONE

reset value: 0x0000_0000

  • DONE: the state of the CRC calculation
    • 1'b0: no done
    • 1'b1: done

Program Guide

The software operation of crc is simple. These registers can be accessed by 4-byte aligned read and write. C-like pseudocode operation:

// for example: CRC16-8005, REVOUT: true, REVIN: true, SIZE: 32
uint32_t val;
crc.CTRL = (uint32_t)0                             // disable the crc core
crc.INIT = INIT_32_bit                             // write the crc init value
crc.XORV = XORV_32_bit                             // write the xor value of crc result
crc.CTRL.[SIZE, MODE, EN] = [0b11, 0b10, 1, 1, 1]  // set the control mode of crc
crc.DATA = VAL_32_bit                              // write the value which need to be calculated
...
while(crc.STAT != DONE){}                          // wait the calculation is end

RES_VALUE = crc.DATA                               // read the result

complete driver and test codes in driver dir.

Resoureces

References

Revision History