Versions >=1.4.0 unstable with Wemos D1 mini

[anduck]

Step 1: Describe your environment

• OS version: Arch Linux
• Arduino IDE version: 1.8.5
• MFRC522 Library version: 1.3.6 (1.3.6 being the last stable version. versions above this are unstable)
• Arduino device: Wemos D1 mini
• MFRC522 device: RFID-RC522

Step 2: Describe the problem

Found out that MFRC522 with Wemos D1 mini is unstable for at least versions 1.4.0 and 1.4.1. Version 1.3.6 was found out to be stable. Unstability means that sometimes MFRC522 device works, sometimes not. It worked roughly 1 out 10 times, when testing. Reset button was used to reset Wemos device between each attempt.

Steps to reproduce:

1. Attach MFRC522 device to Wemos D1 mini according to e.g. https://github.com/Jorgen-VikingGod/ESP8266-MFRC522 "Wiring RFID RC522 module"
2. Get & use MFRC522 library version 1.4.0 or 1.4.1 (via Arduino library manager): sometimes the MFRC522 reader works, sometimes it doesn't
3. Switch to version 1.3.6: reader works without issues

[Rotzbua]

Please test a different pin than D3. D3 is also used to trigger programming/run mode.

Is the problem similar to #426?

[Rotzbua]

@anduck and your esp board version would be good to know. Is it the latest 2.4.2?

[Rotzbua]

As alternative:

Can you try without connected rst and following code?

#define RST_PIN 0xff // Configurable, see typical pin layout above

This disables the hardware pin based reset. Only the software based reset is done.

[anduck]

@Rotzbua Tried with RST pin D1. No change in result.

Yes, this is possibly related to #426 .

How can I check my ESP board version? "Get board info" on Arduino IDE shows nothing like 2.4.2.

Tested unconnecting RST pin and added #define RST_PIN 0xff, reader didn't work on 1.3.6 nor 1.4.2.

[anduck]

Using 1.3.6, I also found out that adding a 100ms delay between mfrc522.PCD_Init(); and mfrc522.PCD_DumpVersionToSerial(); makes it work less often.

[anduck]

Also found out that while 1.3.6 seems to be stable, it's not. It works maybe 9/10 times. Initialization works everytime and it returns version 0x12.

[Rotzbua]

How can I check my ESP board version? "Get board info" on Arduino IDE shows nothing like 2.4.2.

Open Boards Manager from Tools > Board menu and search esp8266

Initialization works everytime and it returns version 0x12.

Firmware version 0x12, was sometimes reported. I guess this are malfunctioned boards and/or power issues.

May check your soldering. If flux is on your board clean it with alcohol. Flux can cause unpredicted current flow.

[anduck]

Ok, thanks. I got esp8266 version 2.4.2.

Did some googling and it looks like version 0x12 is reported by fake boards. Now looking carefully at the board, it indeed does look like a fake. Texts are "bolded" and I can't even read what reads in the main chip in there. Board was bought from ebay.

[Rotzbua]

Ok, that is bad. I hope you get your money back.
I would appreciate if you can make some pictures and post them to #428.

Can I close this issue?

[anduck]

I'll get a genuine board and continue testing. I will report back on that, then if this problem doesn't exist for the genuine board, I guess this issue can be closed.

I'll get some pics of this and post to #428

[Rotzbua]

Thanks 👍

[anduck]

Got a genuine board, running master branch, RST unconnected and it is working properly (stable and reports version 0x92 (v2.0). This means that this issue seems to only be present in the fake Chinese boards.