GD32F450_BMC_BaseCode/app/bmc/AuthChip/CM_RDUSER.c

// Read User Zone
//
// The Read Large User Zone function is used to read data from CryptoMemory devices
// that have greater than 256 bytes in each user zone (AT88SC6416C, and larger)

// CryptoMemory Library Include Files
#include "CM_LIB.h"
#include "CM_I2C.h"
#include "CM_I2C_L.h"
#include "CM_GPA.h"

// Read User Zone
uint8_t cm_ReadLargeZone(uint32_t uiCryptoAddr, uint8_t* pucBuffer, uint8_t ucCount)
{
    uint8_t ucReturn;

    ucCM_InsBuff[0] = 0xb2;
    ucCM_InsBuff[1] = (uint8_t)(uiCryptoAddr>>8);
    ucCM_InsBuff[2] = (uint8_t)uiCryptoAddr;
    ucCM_InsBuff[3] = ucCount;

    // Three bytes of the command must be included in the polynominals
    cm_GPAcmd3(ucCM_InsBuff);
    
    // Read the data
    if ((ucReturn = cm_ReadCommand(ucCM_InsBuff, pucBuffer, ucCount)) != SUCCESS) return ucReturn;
    
    // Include the data in the polynominals and decrypt if required
    cm_GPAdecrypt(ucCM_Encrypt, pucBuffer, ucCount); 

    return SUCCESS;
}