GD32F450_BMC_BaseCode/app/bmc/AuthChip/CM_SRDUSER.c

// Read Small User Zone
//
// The Read Small User Zone function is used to read data from CryptoMemory devices that
// have 256 bytes or less in each user zone (AT88SC3216C, and smaller)

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

// Read Small User Zone
uint8_t cm_ReadSmallZone(uint8_t ucCryptoAddr, uint8_t* pucBuffer, uint8_t ucCount)
{
	uint8_t ucReturn;

    ucCM_InsBuff[0] = 0xb2;
    ucCM_InsBuff[1] = 0;
    ucCM_InsBuff[2] = ucCryptoAddr;
    ucCM_InsBuff[3] = ucCount;

    // Two bytes of the command must be included in the polynominals
    cm_GPAcmd2(ucCM_InsBuff);
    
    // Read the data
    if ((ucReturn = cm_ReadCommand(ucCM_InsBuff, pucBuffer, ucCount)) != SUCCESS) return ucReturn;
	
    // Include the data in the polynominals and decrypt it required
    cm_GPAdecrypt(ucCM_Encrypt, pucBuffer, ucCount); 

    // Done
    return SUCCESS;
}