code: private static byte ascToBcd(byte asc) {
  		byte bcd;
  
  		if ((asc >= '0') && (asc <= '9')) {
  			bcd = (byte) (asc - '0');
  		}else if ((asc >= 'A') && (asc <= 'F')) {
  			bcd = (byte) (asc - 'A' + 10);
  		}else if ((asc >= 'a') && (asc <= 'f')) {
  			bcd = (byte) (asc - 'a' + 10);
  		}else {
  			bcd = (byte) (asc - 48);
  		}
  		return bcd;
  	}
docs: 转换单个byte为BCD
  @param asc ACSII
  @return BCD