RFID and MAX232 connection with microcontroller

• Nov 19, 2012

• #21

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i think no max 232 is available...then how to connect rfid, max232, controller. whether the D0,D1 pin should connect to max 232?

 

• Nov 19, 2012

• #22

ckshivaram

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which RFID module are you using? send the picture of your module or schematic. if you dont have max232 on the rfid board then you may need one circuit for that and a max 232 at the controllerend too. what interface does your rfid module use? first connect rfid module to serial port of pc and in hyperterminal after setting the terminal setting properly swipe the rfid card and see if you see any output printed on the terminal.

 

• Nov 19, 2012

• #23

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i will get the output in Wiegend Protocol then how i want to compare this with the tag ID which i stored in Program

 

• Nov 19, 2012

• #24

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If D0 and D1 are giving TTL o/ps then why do you have to connect it to MAX232? Can't you connect it directly to mcu? What are the pin specifications of D0 and D1?

For Example If The card Shown Above is Placed on the Reader ,
UART Data Will be 159 48659
Parity |---8BIT--|-------16BIT---------------|Parity
Wigend O/p Will be 1 1001 1111 1011 1110 0001 0011 0

 

• Nov 19, 2012

• #25

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check this link...my rfid diagram is available here.
**broken link removed**

- - - Updated - - -

yes it correct..i can connect directly to mcu. The pin D0,D1 will give the wiegend protocol output. where low signal send through D0 and high signal will send through D1.

 

• Nov 19, 2012

• #26

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Yes you have to use MAX232. See this http://www.nskelectronics.com/rfid_reader_-_125khz.html It has Wiegand o/p, TTL o/p, and RS232 o/p.

So if you want RS232 o/p you have to connect MAX232 to TTL lines (3 wires)

if you want to use TTL o/ps then you have to use 3rd product mentioned here http://www.nskelectronics.com/usb__rs232ttlrs485_brds.html with your RFID.

connect RFID o/p to RS232 board TTL i/p and get the RS232 o/p from the D connector and give it to mcu Rx and Tx pins.

 

Last edited: Nov 19, 2012

• Nov 19, 2012

• #27

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i am getting TTL o/p then what is the need of max 232.pls explain it in brief.the rfid which iam using is mentioned below
**broken link removed**

 

• Nov 19, 2012

• #28

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read this http://www.sparkfun.com/tutorials/215
and this http://www.best-microcontroller-projects.com/how-rs232-works.html

Why don't you email nsk electronics people and ask about how to interface your RFID with microcontroller?

 

Last edited: Nov 19, 2012

• Nov 19, 2012

• #29

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can any one expalin how to interface wiegand output to microcontroller unit

 

• Nov 19, 2012

• #30

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Read this http://www.pagemac.com/azure/arduino_wiegand.php

See page 6 here [/url] https://www.robotshop.com/content/PDF/details-description-pr25.pdf [/url]

 

• Nov 19, 2012

• #31

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can u send program in keil C

 

• Nov 19, 2012

• #32

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Read this http://www.dnatechindia.com/Tutorial/8051-Tutorial/Wiegand-Interface.html This mentions how to use weigand. It says weigand o/p can be connected directly to mcu.

Are you using 8051? I have never used 8051 and RFID. I have to think about programming 8051.

 

• Nov 19, 2012

• #33

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thank u so much

 

• Nov 19, 2012

• #34

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See this link, there are links to schematic and sourc codes for PIC using weigand.**broken link removed**
Can you use PIC mcu?

 

Last edited by a moderator: Nov 3, 2021

• Nov 20, 2012

• #35

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it is possible to connect TX PIN of MAX 232 directly to RX pin of 8051

 

• Nov 20, 2012

• #36

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Yes. You can connect Rx and Tx pins of MAX232 to R1OUT and T1In pins of 8051 or any mcu.

See this **broken link removed**

http://www.engineersgarage.com/mic...s/interface-serialport-RS232-AT89C51-circuit

 

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• Nov 20, 2012

• #37

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thank u...can i use this RX Pin of 8051 as interrupt which i connected to TX PIN of MAX 232

 

• Nov 20, 2012

• #38

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I told you I don't know about 8051. Please see the datasheet of 8051.

Read the book "The 8051 Microcontroller and Embedded Systems Using Assembly and C by Muhammad Ali Mazidi, Janice Gillispie mazidi, Rolin D McKinlay"

register and see this link http://www.engineersgarage.com/mic...erface-rfid-AT89C51-serial-interrupt-circuit

there is serial interrupt code using 8051.

 

Last edited: Nov 20, 2012

• Nov 20, 2012

• #39

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can u tell how to get 8bytes of data from RFID using SBUF in microcontroller...iam doing in keil c...but i cant able to collect the data in subf.

- - - Updated - - -

 

• Nov 20, 2012

• #40

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See this http://www.engineersgarage.com/mic...erface-rfid-AT89C51-serial-interrupt-circuit

Post your code.