MicroPython Forum (Archive)

@Zcannon78 : Try Thonny IDE. Good for starters. Your idea of using USB is interesting, though. Not an easy task, it could be a community project, since components using different technologies are required: Based on the USB/REPL interface and Browsers experimental USB-Interface (Chrome + Edge + Oper...

Received the logic analyzer. Here's what I've learned up to now: PICO's I2C timing is not very constant, especially in high frequencies. After pulling SDA to LOW in the ACK pulse, the PN532 keeps the signal LOW for a long time (0.3ms or more. sometimes the signal even remains LOW (Screenshot Ⓞ below...

Agree.
I ordered another two PN532 boards from another supplier. HTH.

«Did you try SoftI2C?» ➝ Same results (see below) «The other board used a different sensor. So you cannot compare the test result.» ➝ This was the tests aim: to prove that the hard- and software test setup besides the PN532 board will work fine for i2C.scan(). Test successful. «…logic analyzers» ➝ ...

@Roberthh: Thank you for your support! I think it's time to use your logic analyzer ➝ I ordered an LA104, will take a week or so. ➝ I'll attend a hackerspace meeting tomorrow. Maybe I'll get learnings there. With additional external power supply (EPS) : stable 3.28V idle and during tests. However, r...

My favorite multimeter is 40 years old. ➝ same :D The display cover glass is VERY yellowish. ➝ I'd expect only short fluctuations during a test, and therefore I didn't even try it. It will still tell you, if Vcc is 3.3V or 3V. ➝ The 3V3 line is 3.26V idle without noticeable drop during a test with ...

@Roberthh: «Vcc decreases during your tests? Can you test it?» ➝ I don't think so. I only have an old bulky CALTEK CM2700 multimeter . « a thermal problem» ➝ no smell in a 30' test, no excess temp registered with my finger on any of the components on the two boards. Have you seen the VERY DIFFERENT ...

@Roberthh: I modified the test protocol above while you were posting your answer. If you look at real delay difference with long delays, every i2c.scan() obviously takes 0.05–0.16s. In iterations with short delays I might step into previous i2c.scan() communication? In response to your questions: Ye...

@karfas : «Unless you get a reliable i2c.scan() result, any other communication will most likely fail.» ➝ fair point! I'll suspend solving the address issue until electrical issues are under control. Adding 4.7kΩ pull-ups seemed to help, but still far from reliable. ➝ As ist seems, repeated i2c.sca...

I connected a PN532 NFC board to my RaspberryPi Pico. Since there's no Micropython Library supporting I2C, I tried to port the Adafruit_CircuitPython_PN532 , motivated by @Roberthh here in this Micropython Forum : «I have ported adafruit libraries a few times, and it was not difficult.» and mimickin...