Pro micro and rc522 rfid

Projects General Guidance
1

Hi,

Hope someone can shed some light!

I have a leonardo and rc522.. all is well, however I need a smaller footprint so pro micro fits the bill.

Purchased a clone off amazon, same code as leonardo, with different rst and sda pins (5 &10 as the build on line).

Will not read a mifare card, good or bad. However passed the rc522 self diagnostics.

I know the rc522 is good.. works with leonardo, other functions of the pro micro are working.. pwm and digital outputs.

Tests done with standard library examples

I was concerned that the voltage divider 10k/20k to get 3.3v might not be giving enough to let the rc522 do its thing (30ma required).. so I built a lm317 regulator. No change.

Suggestions or solutions welcome.

Thanks Ian

2

Purchased a clone off amazon, same code as leonardo, with different rst and sda pins (5 &10 as the build on line).

Neither the Leonardo nor the Micro has SDA on pin 10. Post a complete wiring diagram/schematics and the used code!

3

Sorry not sda, as part of the spi comms method.

The code is from the examples. The only difference between the leonardo version and the pro micro versions are the assignment of rst_pin and ss_pin for the library to use.

I will post the exact code and pin connections later

Thanks

4

odd, just spent 20 mins putting a reply together, hit post & it disapeared... oh well!

OK, code (mine), pin mapping and schematic attached (credit the project forum, PC-Pass, by movano the idiot)

These are the micro version, on the Leonardo version RST -> pin 13 and SS to pin 10, MOSI/MISO and SCK are attached to the ISCP header.

There is more going on in the attached code, however essentially all it does is fade a blue LED, on fail read flash red, on a good read flash green and dump the content of sector 7 to the serial monitor.

As I said I ran the standard example firmware-check from Miguel Balboas library.. I am using the library as supplied!

Trust this can help you shed some light

Thanks ian

read_selden_card_micro_forum.ino (4.22 KB)

rc522 to pro micro pins.jpg

rc522 to pro micro connections.jpg
rc522 to pro micro connections.jpg1362×663 258 KB

5

rc522 to pro micro pins.jpg

rc522 to pro micro connections.jpg

ianmorris1960:
I was concerned that the voltage divider 10k/20k to get 3.3v might not be giving enough to let the rc522 do its thing (30ma required)

You most certainly cannot run an IC from a voltage divider. :astonished:

ianmorris1960:
odd, just spent 20 mins putting a reply together, hit post & it disappeared... oh well!

Not at all odd. Happens all the time. You learn to use Ctrl-A, Ctrl-C before you hit "Preview" if you have been doing a lot of typing.

Please read the instructions (point 7) to understand how to post code to the forum.

6

You can sometimes recover most of a lost reply from your "Drafts":

  • Hover the mouse pointer over your avatar in the top right corner of any arduino.cc page.
  • Click "Profile".
  • Click "Forum Settings > Edit".
  • Click "Show Drafts".

But if the forum is really having problems, sometimes the drafts don't get saved either.

7

Drafts are made every five (I think) minutes if you have made a modification to the reply block.

If that occurred just before you tried to preview, you are lucky. If it happened five minutes ago, then five minutes of work can be lost.

But if the JavaScript itself has failed, it will not have saved the drafts anyway. :roll_eyes:

8

It seems you're not using the MFRC522 chip directly. Post a link to the schematics of the breakout board you're using!

You must use a level converter between the Micro and the MFRC522 (if not already included on the breakout board)! You might damage the MFRC522 if you connect the SPI signals directly to the Micro!