ST25RU3993 - reading registers

[Piotr Szwajda]

Posted on April 10, 2018 at 12:25

Hi,

I'm building an UHF RFID reader using ST25RU3993 and I have a problem reading the registers. The idea is to connect the IC to NodeMCU or Arduino (both are programmed using Arduino IDE at this stage).

I connected MISO to MISO and MOSI to MOSI (I�m assuming there is an error in the datasheet Figure 3 p.15)

After enabling the IC (EN = 1) and waiting 1 second I try to read registers, but the IC does not respond to my SPI messages. I can see NCS, CLK and MOSI signals on the oscilloscope, but the MISO is always LOW. My code reads registers 0x00 to 0x24. The SPI was set to MODE1 (NodeMCU outputs data on rising edge and captures it on Falling edge as instructed in the datasheet p.15).

I tried different frequencies: 1kbps, 100kbps, 1Mbps, 2Mbps and 5Mbps.

According to the datasheet the IC should be in NORMAL mode and therefore the SPI communication should be possible after enabling the device.

I also see voltages at some of the pins (voltage regulators) so the device is powered up and is working. At least some parts of it. I have been assembling the board at home so there is a possibility that I fried it. I don�t want to buy a new chip before I�m sure this one is damaged.

Is there anything that I�m doing wrong? Did I forget about some procedure?

Please help!

#uhf-rfid-reader-st25ru3993 #registers

[Piotr Szwajda]

Posted on April 10, 2018 at 12:41

I forgot to mention that I send MSB first. 

[Piotr Szwajda · Accepted solution]

Posted on April 11, 2018 at 18:21

Problem solved. It was a silly hardware error. 

Arduino ProMini 3V reads the registers.

[João Carlos Silva dos Santos]

Posted on May 07, 2018 at 16:32

Hi,

I'm doing the same over here. I had faced several problems in the beginning, I had to port several parts of the code, but now I'm able to initialize the ST25RU3993 using NodeMCU at ArduinoIDE. 

I hope to get the inventory round working soon.