RFID reader interfacing to PSOC3

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cross mob
Anonymous
Not applicable

 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 

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Bob_Marlowe
Level 10
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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

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ETRO_SSN583
Level 9
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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.

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ETRO_SSN583
Level 9
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I forgot this is RFID, generally speaking data rates not all that high,

   

so code execution time may be irrelevant.

   

 

   

Regards, Dana.

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Anonymous
Not applicable

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

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Bob_Marlowe
Level 10
Level 10
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You are always welcome!

   

 

   

Bob

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