Incorporating time stamp with RFID reader

pja

I am incorporating a time stamp into the supplied program for reader RFIDs. I want the debug menu to display how long it took the reader to detect the RFID tag.

I tried this with a loop that lasted 1 ms and recorded how many milliseconds it took for the Reader to see the tag. This simple code was demonstrated in the manual that comes with the Basic Stamp microprocessor. Unfortunately I have not found the correct way to integrate the loop with the program. I tried putting the loop before the rest of the program and it doesn't work correctly. I have also tried putting the loop after the program and it does not record the time.

Any suggestions?


The loop program is simply
timecounter VAR Word
timecounter = 0
DO
PAUSE 1
timecounter = timecounter + 1
LOOP UNTIL (IN1 =0)

The RFID reader program is:
'

---

[noparse][[/noparse] I/O Definitions ]

---

Enable PIN 0 ' low = reader on
RX PIN 1 ' serial from reader
Spkr PIN 2 ' speaker output
Latch PIN 3 ' lock/latch control


'

---

[noparse][[/noparse] Constants ]

---

#SELECT $STAMP
#CASE BS2, BS2E, BS2PE
T1200 CON 813
T2400 CON 396
T4800 CON 188
T9600 CON 84
T19K2 CON 32
TMidi CON 12
T38K4 CON 6
#CASE BS2SX, BS2P
T1200 CON 2063
T2400 CON 1021
T4800 CON 500
T9600 CON 240
T19K2 CON 110
TMidi CON 60
T38K4 CON 45
#CASE BS2PX
T1200 CON 3313
T2400 CON 1646
T4800 CON 813
T9600 CON 396
T19K2 CON 188
TMidi CON 108
T38K4 CON 84
#ENDSELECT

SevenBit CON $2000
Inverted CON $4000
Open CON $8000
Baud CON T2400


#SELECT $STAMP
#CASE BS2, BS2E
TmAdj CON $100 ' x 1.0 (time adjust)
FrAdj CON $100 ' x 1.0 (freq adjust)
#CASE BS2SX
TmAdj CON $280 ' x 2.5
FrAdj CON $066 ' x 0.4
#CASE BS2P
TmAdj CON $3C5 ' x 3.77
FrAdj CON $044 ' x 0.265
#CASE BS2PE
TmAdj CON $100 ' x 1.0
FrAdj CON $0AA ' x 0.665
#CASE BS2PX
TmAdj CON $607 ' x 6.03
FrAdj CON $2A ' x 0.166
#ENDSELECT


LastTag CON 3


#DEFINE __No_SPRAM = ($STAMP < BS2P) ' does module have SPRAM?


'

---

[noparse][[/noparse] Variables ]

---

#IF __No_SPRAM #THEN
buf VAR Byte(10) ' RFID bytes buffer
#ELSE
chkChar VAR Byte ' character to test
#ENDIF

tagNum VAR Nib ' from EEPROM table
idx VAR Byte ' tag byte index
char VAR Byte ' character from table


'

---

[noparse][[/noparse] EEPROM Data ]

---

Tag1 DATA "0101A625F5" ' random number
Tag2 DATA "0F02A69268" ' Tag at hand 1
Tag3 DATA "0F02A693F1" ' Tag at hand 2

Name0 DATA "Unauthorized", CR, 0
Name1 DATA "Tag 1 (White Card)", CR, 0
Name2 DATA "Tag 2 ", CR, 0
Name3 DATA "Tag 3 ", CR, 0


'

---

[noparse][[/noparse] Initialization ]

---

Reset:
HIGH Enable ' turn of RFID reader
LOW Latch ' lock the door!


'

---

[noparse][[/noparse] Program Code ]

---

Main:
LOW Enable ' activate the reader
#IF __No_SPRAM #THEN
SERIN RX, T2400, [noparse][[/noparse]WAIT($0A), STR buf\10] ' wait for hdr + ID
#ELSE
SERIN RX, T2400, [noparse][[/noparse]WAIT($0A), SPSTR 10]
#ENDIF
HIGH Enable ' deactivate reader

Check_List:
FOR tagNum = 1 TO LastTag ' scan through known tags
FOR idx = 0 TO 9 ' scan bytes in tag
READ (tagNum - 1 * 10 + idx), char ' get tag data from table
#IF __No_SPRAM #THEN
IF (char <> buf(idx)) THEN Bad_Char ' compare tag to table
#ELSE
GET idx, chkChar ' read char from SPRAM
IF (char <> chkChar) THEN Bad_Char ' compare to table
#ENDIF
NEXT
GOTO Tag_Found ' all bytes match!

Bad_Char: ' try next tag
NEXT

Bad_Tag:
tagNum = 0
GOSUB Show_Name ' print message
FREQOUT Spkr, 1000 */ TmAdj, 115 */ FrAdj ' groan
PAUSE 1000
GOTO Main

Tag_Found:
GOSUB Show_Name ' print name
HIGH Latch ' remove latch
FREQOUT Spkr, 2000 */ TmAdj, 880 */ FrAdj ' beep
LOW Latch ' restore latch
GOTO Main

END


'

---

[noparse][[/noparse] Subroutines ]

---

' Prints name associated with RFID tag

Show_Name:
DEBUG DEC tagNum, ": "
LOOKUP tagNum,
[noparse][[/noparse]Name0, Name1, Name2, Name3], idx ' point to first character
DO
READ idx, char ' read character from name
IF (char = 0) THEN EXIT ' if 0, we're done
DEBUG char ' otherwise print it
idx = idx + 1 ' point to next character
LOOP
RETURN

Franklin

You won't be able to do it with the code you have. You need to use an external time chip or have a main loop that executes in an exact, repeatable and known time. If the loop was repeatable then you would add the time of the loop to the counter and when the next tag was read the counter would be printed then cleared for the next tag. Like I said you haven't done this and I'm not sure it is possible.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
- Stephen