Cant read user data from RFID card, using 28440 R/W, and writable card.
Patrick Coleman
Posts: 43
I'm having trouble writing to and reading the user data from the R/W card ( https://www.parallax.com/product/28441 ) using the ( https://www.parallax.com/product/28440 ) device. Ive searched the forum, and used the demo code, but cant get the writable and read-back part to work. It will read the unique serial hex, but nothing else. After a short time, it will say "Success! End of test"
I bought the 2.49 USD card which should have the R/W capability.
I don't see where the part of the code:
DEBUG "Writing and verifying data to tag..."
Write_Tag:
SEROUT RFID_TX, Baud, ["!RW", RFID_Write, 3, $FE, $ED, $BE, $EF] ' Write $FEEDBEEF into address 4 (user EEPROM area)
Would fail, but it should report "FEEDBEEF" when read back.
I'm using the Basic stamp 2.
Please help
Thank you,
I bought the 2.49 USD card which should have the R/W capability.
I don't see where the part of the code:
DEBUG "Writing and verifying data to tag..."
Write_Tag:
SEROUT RFID_TX, Baud, ["!RW", RFID_Write, 3, $FE, $ED, $BE, $EF] ' Write $FEEDBEEF into address 4 (user EEPROM area)
Would fail, but it should report "FEEDBEEF" when read back.
I'm using the Basic stamp 2.
Please help
Thank you,
Comments
Yes, I can see if I get rid of the "pause 2000" then it will run through many times, so the proximity cant be the issue. I must be making a programming error.
I'm using the Basic Stamp 2, and have tried the demo code. but I just don't see why I cant read the 116 byte eeprom.
I bought the 28440 RW, and the more expensive card (2.49 $).
I just don't know what to do, and would like to be able to write a short sting of characters to the card, and read them back.
also, ive looked at the PDF, but cant get this stuff to work either.
Command Set
0x01: RFID_Read
Read data from a specified address Input: Address location (1 byte), valid locations are 1-33 decimal Output: Status byte (1 byte) + data (4 bytes) Example: SEROUT RFID_TX, Baud, ["!RW", RFID_Read, ADDR_Serial] ' Read tag's serial number SERIN RFID_RX, Baud, [err, STR data\4] ' Get status byte & data bytes
0x02: RFID_Write
Write data to a specified address Input: Address location (1 byte), valid locations are 3-31 decimal + data (4 bytes) Output: Status byte (1 byte) Example: ' Write $FEEDBEEF to address 3 (User Data Area) SEROUT RFID_TX, Baud, ["!RW", RFID_Write, 3, $FE, $ED, $BE, $EF] SERIN RFID_RX, Baud, [err] ' Get status byte
Note: After writing the specified data to the tag, the RFID Read/Write Module automatically performs a read function to verify that the data has properly been written.
The physical parts are fine. I bought 7 cards, a reader and a BS2. the system works fine with reading the serial data of the round black "world" and other tags, obviously only reading with no data user read back because they don't have that ability..
This is for a drone Kickstarter, so I need this figured out in the next 7-10 days to stay on schedule, ill be moving the burn test up to keep on track.
You mentioned,
From my understanding, you loaded the rfid_rw_test.bs2; and expecting to see the values written to the tag. If so, the rfid_rw_test.bs2 code, will not report any values. It reads the tag's unique serial number prints it; then prints "Writing and verifying data to tag..."; without printing any values. The code then "behind the scenes" keeps trying if an error occurs, until it successfully writes and verifies data to the tag. And finally prints "success" as shown on the terminal in the first picture <rfid_rw_test> below.
The rfid_rw_demo.bs2 code, on the other hand reports the tag's memory contents and prints it. As shown in the second picture <rfid_rw_demo>.
After you load the rfid_rw_demo.bs2 code into your board, please report back to me what you are seeing in the terminal. If your code gets stuck at some point, keep your tag in range; and let me know if that fixes the issue.
Respectfully
Zakia Ben Youss
Technical Support
Parallax, inc