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I am trying to build an RFID based door opener with an Attiny2313 and an RDM630 RFID reader. There has been no Problem with programming or getting the two ICs to talk to each other via UART. The Problem is the interpretation of the data. I wasn't able to make any sense of what the RDM630 had sent to the Attiny, so I hooked it up via an RS232/USB Adapter, and this is what I get on my PC:

Display = ASCII: ascii screen shot

Display set to HEX: hex screen shot

Written on the Card is: 0000714511 010,59151

Can anyone help me make sense of the Data?

Barett
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Daniel Blubberlutsch
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  • Did you connect the right PIN (from the datasheet it looks as if PIN2 outputs what you want) to the RS232/USB adapter? And that adapter supports TTL levels, right? – Michael Roland May 12 '15 at 05:29
  • PIN2 is connected to the TXD of the Adapter, if i connect them the other way around, no data is being sent. I do not know for certain, but i am pretty sure the adapter supports TTL, since my Professor gave it to me. – Daniel Blubberlutsch May 16 '15 at 11:50

1 Answers1

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Most of the bytes that the RDM630 RFID reader module sends are ASCII characters of hex digits ('0'-'9','A'-'F') which means 0x30-0x39, 0x41-0x46.

It looks like your RS232/USB inverts the bits, comparing to a direct TTL connections.

(RS232 is inverted TTL. It has also different voltage levels, but that's OK as long as TTL transmit output feeds RS232 receive input, as in your case. The other way around is more tricky).

Swati
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Yoram Grinberg
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