Debugging 28440 RFID reader
djbennett163
Posts: 3
My RFID reader is not working. I have a BoE with BS2 Rev J.
Connections like this:
VDD to pin 1 of 28440 (VCC)
VSS to pin 4 of 28440 (GND)
Pin 0 to pin 2 (SIN)
pin 1 to pin 3 (SOUT)
When I run, the LED on 28440 turns green as code is transferred and led on BoE blinks as usual. When that is done, turns RED (Active). Pressing and holding reset swithc will show green on 28440, and it turns red when reset switch is relased and program runs. Sounds good? However holding my 28141 card up to it produces no response. I checked the current through the RFID reader and when it is active it is around 65 mA. My meter shows a jump to 400 some mA when program starts... is that an indication of what is wrong?
Connections like this:
VDD to pin 1 of 28440 (VCC)
VSS to pin 4 of 28440 (GND)
Pin 0 to pin 2 (SIN)
pin 1 to pin 3 (SOUT)
When I run, the LED on 28440 turns green as code is transferred and led on BoE blinks as usual. When that is done, turns RED (Active). Pressing and holding reset swithc will show green on 28440, and it turns red when reset switch is relased and program runs. Sounds good? However holding my 28141 card up to it produces no response. I checked the current through the RFID reader and when it is active it is around 65 mA. My meter shows a jump to 400 some mA when program starts... is that an indication of what is wrong?
' =========================================================================
'
' File...... rfid_rw_demo.bs2
' Purpose... Demonstration code for the Parallax RFID Read/Write Module
' Author.... Joe Grand, Grand Idea Studio, Inc. [www.grandideastudio.com]
' E-mail.... support@parallax.com
' Updated... 15 Dec 2009
'
' {$STAMP BS2}
' {$PBASIC 2.5}
'
' =========================================================================
' -----[ Program Description ]---------------------------------------------
'
' This program demonstrates the capabilities of the Parallax RFID Read/
' Write Module.
'
' Compatible with EM Microelectronic EM4x50 1kbit R/W 125kHz tags.
' These tags can be used in a number of ways:
' 1) Read-only by reading the tag's unique, non-changing serial number
' 2) Read/write up to 116 bytes of user data (publicly accessible)
' 3) Read/write up to 116 bytes of user data (password protected)
' -----[ I/O Definitions ]-------------------------------------------------
RFID_TX PIN 0 ' Connects to RFID R/W Module SIN
RFID_RX PIN 1 ' Connects to RFID R/W Module SOUT
' -----[ Constants ]-------------------------------------------------------
#SELECT $STAMP
#CASE BS2, BS2E, BS2PE
T9600 CON 84
#CASE BS2SX, BS2P
T9600 CON 240
#ENDSELECT
Baud CON T9600
' RFID R/W Module Commands
' Number of bytes returned in ()
RFID_Read CON $01 ' Read data from specified address, valid locations 1 to 33 (5)
RFID_Write CON $02 ' Write data to specified address, valid locations 3 to 31 (1)
RFID_Login CON $03 ' Login to tag with password (1)
RFID_SetPass CON $04 ' Change tag's password from old to new (1)
RFID_Protect CON $05 ' Enable/disable password protection (1)
RFID_Reset CON $06 ' Reset tag (1)
RFID_ReadLegacy CON $0F ' Read unique ID from EM4102 read-only tag (for backwards compatibility with Parallax RFID Card Reader, #28140 and #28340) (12)
' Memory map/address locations for EM4x50 tag
' Each address holds/returns a 32-bit (4 byte) value
ADDR_Password CON 0 ' Password (not readable)
ADDR_Protect CON 1 ' Protection Word
ADDR_Control CON 2 ' Control Word
' ADDR 3-31 are User EEPROM area
ADDR_Serial CON 32 ' Device Serial Number
ADDR_DeviceID CON 33 ' Device Identification
' Status/error return codes
ERR_OK CON $01 ' No errors
ERR_LIW CON $02 ' Did not find a listen window
ERR_NAK CON $03 ' Received a NAK, could be invalid command
ERR_NAK_OLDPW CON $04 ' Received a NAK sending old password (RFID_SetPass), could be incorrect password
ERR_NAK_NEWPW CON $05 ' Received a NAK sending new password (RFID_SetPass)
ERR_LIW_NEWPW CON $06 ' Did not find a listen window after setting new password (RFID_SetPass)
ERR_PARITY CON $07 ' Parity error when reading data
' -----[ Variables ]-------------------------------------------------------
buf VAR Byte(12) ' data buffer
idx VAR Byte ' index
idy VAR Byte
' -----[ EEPROM Data ]-----------------------------------------------------
' -----[ Initialization ]--------------------------------------------------
Initialize:
PAUSE 250 ' let DEBUG open
DEBUG CLS ' clear the screen
DEBUG "Parallax RFID Read/Write Module Demo Application", CR,
"------------------------------------------------", CR, CR
' -----[ Program Code ]----------------------------------------------------
Main:
' Code blocks can be commented/uncommented/rearranged to
' experiment with the available features and operations of the
' Parallax RFID Read/Write Module
DEBUG "Reading tag's unique serial number..."
Read_Tag:
SEROUT RFID_TX, Baud, ["!RW", RFID_Read, ADDR_Serial] ' Read tag's serial number
SERIN RFID_RX, Baud, [STR buf\5] ' Get status byte and data bytes
IF buf(0) <> ERR_OK THEN Read_Tag ' If we get an error, keep trying until the read is successful
FOR idx = 1 TO 4 ' Print data
DEBUG HEX2 buf(idx)
NEXT
DEBUG CR
DEBUG "Reading Legacy tag's unique serial number..." ' Read unique ID from EM4102 read-only tag
Read_Legacy:
SEROUT RFID_TX, Baud, ["!RW", RFID_ReadLegacy]
SERIN RFID_RX, Baud, [STR buf\12] ' Get header and data
IF buf(0) <> $0A THEN Read_Legacy ' If we don't receive the correct header, keep trying until we do
FOR idx = 1 TO 10 ' Display the data (ignore final \r byte sent by the reader)
DEBUG buf(idx)
NEXT
DEBUG CR
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 3 (user EEPROM area)
SEROUT RFID_TX, Baud, ["!RW", RFID_Write, 3, $FF, $EE, $BB, $EE]
SERIN RFID_RX, Baud, [buf(0)] ' Wait for status byte
IF buf(0) <> ERR_OK THEN Write_Tag ' If we get an error, keep trying until the write is successful
DEBUG "Done!", CR
DEBUG "Reading tag's entire memory contents:", CR
FOR idy = 1 TO 33
Read_Tag2:
SEROUT RFID_TX, Baud, ["!RW", RFID_Read, idy] ' Read data from address location "idy"
SERIN RFID_RX, Baud, [STR buf\5] ' Get status byte and data bytes
IF buf(0) <> ERR_OK THEN Read_Tag2 ' If we get an error, keep trying until the read is successful
DEBUG DEC2 idy, ": "
FOR idx = 1 TO 4 ' Print data
DEBUG HEX2 buf(idx)
NEXT
DEBUG CR ' Repeat for address locations 1 to 33
NEXT
' Login is only required to take advantage of the password protection features
' e.g., set the tag's password, lock/unlock the tag, or read/write the tag (if tag is locked)
DEBUG "Logging into the tag..."
Login:
SEROUT RFID_TX, Baud, ["!RW", RFID_Login, REP $00\4] ' Login to tag with default password of $00000000
SERIN RFID_RX, Baud, [buf(0)] ' Wait for status byte
IF buf(0) <> ERR_OK THEN Login ' If we get an error, keep trying until login is successful
DEBUG "Done!", CR
DEBUG "Changing tag's password..."
Set_Pass:
SEROUT RFID_TX, Baud, ["!RW", RFID_SetPass, REP $00\4, REP $00\4] ' Change password from old ($00000000) to new ($00000000)
SERIN RFID_RX, Baud, [buf(0)] ' Wait for status byte
IF buf(0) <> ERR_OK THEN Set_Pass ' If we get an error, keep trying until the password change is successful
DEBUG "Done!", CR
DEBUG "Locking tag..."
Lock_Tag:
SEROUT RFID_TX, Baud, ["!RW", RFID_Protect, 1] ' Enable read/write password protection of the entire tag
SERIN RFID_RX, Baud, [buf(0)] ' Wait for status byte
IF buf(0) <> ERR_OK THEN Lock_Tag ' If we get an error, keep trying until the function is successful
DEBUG "Done!", CR
DEBUG "Unlocking tag..."
Unlock_Tag:
SEROUT RFID_TX, Baud, ["!RW", RFID_Protect, 0] ' Disable read/write password protection of the entire tag
SERIN RFID_RX, Baud, [buf(0)] ' Wait for status byte
IF buf(0) <> ERR_OK THEN Unlock_Tag ' If we get an error, keep trying until the function is successful
DEBUG "Done!", CR
DEBUG "Resetting the tag..."
Reset_Tag:
SEROUT RFID_TX, Baud, ["!RW", RFID_Reset] ' Log out and reset the tag (will require a re-login if trying to access a locked tag after this point)
SERIN RFID_RX, Baud, [buf(0)] ' Wait for status byte
IF buf(0) <> ERR_OK THEN Reset_Tag ' If we get an error, keep trying until the function is successful
DEBUG "Done!", CR
DEBUG "------------------------------------------------", CR
PAUSE 1000
GOTO Main ' Do it all over again!
END
' -----[ End of File ]----------------------------------------------------
Comments
I was using a Parallax #28141 card. I bought some 28441's and 32398. These work, but I also had to change from the larger amperage power supply which was not regulated and measured 5.27 volts, to the power supply on the Boe. That got it going.