Hi,
I am trying to build an RFID reader with status in OLED, but I get some trouble from sda pin. I can't specify the RFID address, my question is, how can I change the address from the RFID so this device can run simultaneously?
and this is the wiring diagram
Post a link to the specs of your RFID reader.
Because most RFID reader chips while being capable of I2C are sold on boards that are not pined out to allow this mode of communication. The cheap RFID reader boards can use SPI only.
maybe look like this on Indonesian e-commerce
I think on that board, even though it makes SDA and SCL pins available, you cannot use them. The board can use only SPI communications unless you make some modifications to the PCB, which is something only an expert with the correct equipment can achieve.
So you must connect the reader with SPI bus. There are no addresses on SPI bus, so there should be no problems making the OLED work simultaneously with the reader because they are using completely different busses.
Unfortunately this will leave very few pins available on your wemos. If that is a problem, one solution could be to get an OLED with SPI bus. These are less common but they are available. This way, the OLED and reader will share MISO, MOSI and SCK pins, and each will have separate SS pins. So only 5 pins instead of 6, saving 1 pin.
Thank you for your reply.
I will try to cut sda pin from RFID and connect It to another pin
We have done our best to help and advise you. But I suspect you cannot understand it. Good luck with your project
Let me tell you. I have been doing electronics for over 50 years and I am quite skilled with modifying PCB boards and requiring pins. I would not attempt this modification to this board, because of the package the chip is in the tracks can approach the pins from underneath the chip. Unless you have the correct soldering equipment you stand no chance.
The link you posted says
- The module use a voltage of 3.3V, it can connected communication with user's any CPU mainboard through several lines of SPI interface, it can ensure stable and reliable work, and reader distance.
Also if you change it to an I2C interface then the standard library will not work and it would have to be modified.
I would be tempted to change the Arduino to a 3V3 one with more pins.
@ZX80 not sure what that link is about but it is for an SPI interface not an I2C interface.
I don't think there is any I2C interface on that module.
https://blog.jeronimus.net/2018/03/rfid-and-wemos-d1-mini-1.html
oups sorry...
https://forum.arduino.cc/t/rc522-rfid-rc522-switching-spi-to-uart-interface-or-i2c-possible/425741
No, your advice is so good, what I mean is my own PCB. not the RC522 module
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