Fast block write using an indirect memory pointer
View Patent ↗A fast block write command includes providing an RFID tag having a memory, and using a stored address pointer to point to a known address in the memory, wherein the stored address pointer points to a starting address at a known safe block in the memory. The method is performed without an intermediate buffer. The received data is written to the known safe block and a cyclic redundancy check is computed on the received data. If the cyclic redundancy check matches, the received data is retained and the stored address pointer is updated. If the cyclic redundancy check does not match, the stored address pointer is kept for a future write operation. Further block writes can be disallowed after an initial successful block write.
1. A method for writing received data to a memory in an RFID, the method comprising:
maintaining an address pointer in the memory of the RFID tag;
storing in the address pointer a starting address of a safe block in the memory;
receiving an EPC block write command containing data to be written to the memory and comprising a trigger address;
recognizing the trigger address as an instruction to write to the safe block;
writing the received data directly to the safe block beginning at the starting address without using buffer memory;
computing a cyclic redundancy check (CRC) value on the received data; and
updating the starting address stored in the address pointer to point to a new safe block in the memory when the CRC value indicates the data was correctly received.
2. The method of claim 1 further comprising keeping the starting address stored in the address pointer for a subsequent write operation when the CRC check value indicates the data was received incorrectly.
3. The method of claim 1 further comprising disallowing further block writes after an initial successful block write.
4. The method of claim 1 further comprising using an RFID tag having a FRAM memory.
5. The method of claim 1 wherein the beginning address of the new safe block in the memory is designated as a memory location immediately following the memory block in which the received data was written.
6. A Radio Frequency Identification (RFID) system comprising:
an RFID tag configured to transmit and receive wireless signals from an RFID reader, configured to perform CRC decoding of a signal received from the reader and comprising a memory having an address pointer at a fixed location in the memory;
wherein, upon reception of a an EPC block write command from the RFID reader containing data that is to be stored on the RFID tag and comprising a trigger address, the RFID tag is configured to:
store in the address pointer a starting address of a safe block in the memory;
recognize the trigger address as an instruction to write to the safe block;
write the data directly to the safe block beginning at the starting address without using buffer memory;
compute a cyclic redundancy check (CRC) value of the received data; and
update the starting address stored in the address pointer to point to a new safe block in the memory beginning when the CRC value indicates the data was correctly received.
7. The system of claim 6 , wherein the RFID tag is configured to keep the starting address stored in the address pointer for a subsequent write operation when CRC value indicates the data was not received correctly.
8. The system of claim 6 wherein the RFID tag is configured to disallow further block writes after an initial successful block write.
9. The system of claim 6 wherein the memory of the RFID tag comprises a FRAM memory.
10. The system of claim 6 wherein the beginning address of the new safe block in the memory begins at a memory location immediately following the memory block in which the received data was written.