I am tryng to moify your RFID example to work with the parralax board ( 2400 baud and non inverted data) and I am missing something as I can't get ti ti work.

Hi Bob,

You'll probably need to share a little more details to help people help you on this one. Assuming you are talking about the ID12 reader, I suspect they simply don't work in the same way.

By the parallax reader, I assume you mean:

• http://www.parallax.com/tabid/768/ProductID/114/Default.aspx

If so, a quick look at there datasheet suggests it provides a USB interface, and a TTL 2400 baud, non-inverted 8N1 format, which should work with the mbed ok.

It looks like there is an indicator led, which will help confirm it is wired up ok (e.g. the module is powering up ok, and ENABLE is tied to 0v to enable the reader). It suggests GREEN is powered, and RED is active and searching/reading.

So obviously a good sanity check is, is the LED on? RED?

Assuming that is ok, then what the reader does looks to be generate a string of 12 characters. So, is it doing this?

For example, you could write a simple text program:

#include "mbed.h"

Serial rfid(NC, p10); // rfid reader output wired to p10

int main() {
    printf("Hello World!\n");

    rfid.baud(2400);

    while(1) {
        char c = rfid.getc(); // read a character from the RFID reader
        printf("0x%0X\n", c); // display the hex code to the PC terminal
    }
}

Now, if you fire up a terminal, it should then print Hello World!, then any data sent from the RFID reader.

I suspect if you get this far, you have solved your problem!

Simon

Simon

Thanks for the quick reply.  Yes I am using the parallax reader with the TTL output.   Radio Shack has them on clearance for $9.99  It is wired correctly and have verified its operation by using it with level convertor to read  tags via the serial port on my PC.  Red light is on.  I will try  your test program .  Thanks again.

Bob

Works great.  Thanks Simon.  Now will work on balance of system.

Bob