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RFID reader interfacing to PSOC3 | Cypress Semiconductor

RFID reader interfacing to PSOC3

Summary: 5 Replies, Latest post by Bob Marlowe on 11 Nov 2012 07:55 AM PST
Verified Answers: 0
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vardhan's picture
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2 posts

 i'm in a dilemma whether to use the internal default ISR or a user defined one when my RX buffer size is greater tha 4 bytes and when i tried using the UART example project for PSOC3 it worked fine with the hyperterminal doesn't the same code apply to a RFID  reader interfacing ?? when i tried using the same code my LCD wasn't displaying anything...what might be the problem ?? and when we set our buffer size 12 bytes ...when is the recieve interrupt actually generated after it recieves the first byte or after 12 bytes?? in need of urgent help 

user_1377889's picture
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10803 posts

As you can see when changing the buffer size for the Rx-Buffer the interrupt for receiving a character is grayed out. That is because the software takes over to handle incoming characters and put them into the buffer. So just the remaining Rx-interrupt causes as overrun, parity and similar errors will be used. There is a chance to include some code in the UART's interrupt handler at the point a character is received.

I would suggest you to start writing your own code and handler. Begin with a non-interrupt solution which polls for the buffer containing the number of characters you expect(12) but choose a buffer-size that is larger. That can give you some headroom when processing on message and there is no time to poll.

 

Happy coding

Bob

user_14586677's picture
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7648 posts

Leaving the Rx buffer at 4 bytes, using the Rx buffer ISR, certainly

implementing a fifo copy into a buffer with a address pointer straight

forward. This approach requires you look at code execution time,

especially at higher baud rates.

 

Alternatively use component editor and create your own, or use verilog to

create your own handler.

 

It would be advisable, for error reasons, if there was a framing byte or indication

of some sort for the 12 bytes.

 

Regards, Dana.

user_14586677's picture
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7648 posts

I forgot this is RFID, generally speaking data rates not all that high,

so code execution time may be irrelevant.

 

Regards, Dana.

vardhan's picture
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2 posts

 Thanx guys for your valuable advises i'll try out the suggestions made by you and get back to ypu

user_1377889's picture
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10803 posts

You are always welcome!

 

Bob

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