 We are going to special features of the SD25DV. The special features of the SD25DV include data protection, fast transfer mode, GPO, interfaces arbitration, RF management, energy harvesting, power management, capability container file, and NDEV. First we're going to look at data protection. The data and system configuration in the SD25DV memory can be protected with security sessions and passwords. Security sessions are open when correct passwords are presented. There are five 64-bit passwords that are available for users. Four of which are for RF accesses and one is for I2C access. A 64-bit password has 18.5 quintillion combinations. It presented at a rate of half a second. It probably takes 3 billion years to exhaust all the combinations. However, the password is not encrypted and it blows. There's no way to retrieve it. The data and system configuration in the SD25DV memory can be protected with security session and password. Security sessions are open when correct passwords are presented. The user memory is now divided into four configurable areas versus sector granularity as in the previous product M24LR. The configurable parameter includes size and read-write access protection. There are three main registers. The ENDA register configure the sizes. The RFAAI SS registers configure the RF access protection. And finally, the I2CSS register configure I2C access protection. So areas are protected independently in RF and I2C. The RFAA registers from 1 to 4 set read-write protection for area 1 and 4. And the I2CSS registers define read-write protection for area 1 to 4. Area 1 is always readable by both I2C and RF. And resizing area has no effect on RFAA and I2CSS registers. Let's look at an example of data protection. Here the user memory area 1 has RFAAI SS register set at 05 hex. RF read allow but RF write protected. The I2CSS register sets at 01 hex meaning I2C read allow but I2C write protected. When correct RF password 1 is presented user can now write VRF to area 1 but it remains locked VRF with the I2C interface. If incorrect RF password 1 is presented or co-even correct RF password 2 the memory cannot be written to. RF password 0 or password 0 controls the RF write access of static system configuration. For modification of these registers via I2C you need to present I2C password. Dynamic registers are not write protected so you can always read and write without presenting any password. Some dynamic registers are read only. Now let's look at data protection. We are going to do some example in data protection. Let's use the ST25DV data protection mechanism in a real-life application. We will create a business card that has two identities. One public and the other is secret. While the clock hands slash Superman is for illustrative. Real-life example can mean secret data of the product covering things like operational history, life cycles, etc. Information that is useful for the manufacturers but not essential for the final user. We will create two memory areas. Area 1 will be read only and area 2 can be read only if a password is presented. Using the ST25DV discovery board click on the ST25DV icon and when another menu opens up click on area button. Here you can see that there are two areas. One is read only and the other is no access unless password one is presented. Now use the ST25R3911B reader board and the GUI software. Click on ST25 tag editor button. Under ISO 15693 tab and dynamic tags choose ST25DV04K and select EE Prom tab. First set RF block from 40 to 40F hex. Then click read single block. You will see that memory blocks from 40 to 47 can be read but memory blocks from 48 to 4F cannot. Let's access that secret data by presenting RF password one which is all zero by default. Click on password tab and in the password number box click password one and then click present password. This action opens up a dialog box so that you can complete step 4 and step 5. Now complete the read single block command with RF blocks from 40 to 4F hex. And you will see that data in those blocks are now visible. Next we are going to look at the GPO. The GPO is used to wake up I2C host. 7 RF events can be gated. The microcontroller determines what type of event is triggered by reading the IT STS dynamic register. You can also disable the GPO output via the microcontroller to prevent unwanted wake up. The RF reader also can drive the GPO pin level directly. There are two flavors of GPO and availability is based on certain version of devices. Part number that ends with IE supports open drain GPO. Active low and a pull up register is needed. Here power consumption depends on register values and voltage used. Part number that ends with JF supports CMOS GPO. Active high with VDCG supply. This is also the 12 pin package. The advantage of this version is power consumption which can be less than 100 nano amp. In this diagram the RF field detection feature is one of the features which are supported by the GPO pin. In open drain configuration an active low pulse is seen when the field is on and another active low pulse is seen when the field is off. Being able to detect the removal of the RF is also important. The microcontroller can output a by message and then go to standby mode. To set the GPO for interrupts such as field detection you need to configure either static or dynamic registers. Please refer to the datasheet for setting other interrupts features. Let's go through some exercise with the SD25DV GPO feature. We are going to observe the effect when RF interrupts, RF activity and RF field detections are active. We will start from the main GUI window. Click on ISO 15693 tab and subsequently the configuration button. The RF field will be turned on. You can see visually by a blue transmitter LED on the SD25R3911B discovery board. On the SD25DV discovery board, tap on SD25DV button and then the RF GPO button. At this point the board will put out a message saying that it is waiting for a source of RF interruption. Move the reader board so that it is within proximity of the SD25DV discovery antenna. Move in and out of the field until you see a pattern of triggering effect as registers, as field on and off counts. Also notice the distance at which you will see a detection. Now make sure the reader and tags are in RF connection. Click on ISO 15693 and configuration so that you can see that the RF field is on like we had before. We then proceed to put in the managed GPO command with the RF interrupt value. Enter the value in the box and click send receive button. You will see that the board detects the GPO manipulation command coming from the reader. Now we are going to look at interface arbitration. It is important to understand the arbitration between RF and I2C in the SD25DV. First access is exclusive and works on a first come first serve basis. When I2C is busy, RF cannot access. It spends the time from the I2C start to I2C start. Responses are different though. Address, RF request, inventory, stay quiet, select, and reset to ready command are not answered. All the RF commands are answered with error code 0F. When RF is busy, it spends the time from RF request start of frame to answer end of frame.