10 years, 8 months ago.

Depending on the code you use, the HC-SR04 might require an InterruptIn pin, those can only be used on pins markes as IntIn on the handbook page (or something like that). That should be fixed (all pins can be interrupt inputs), no idea when though. If that is the case it should tell you on your serial terminal that it cannot used that pin as interruptin, but i don't know if the Nucleos do that properly (quite frankly, for the same price you get KLxxZ, which has way better device code atm).

If you import a helloworld program you don't need to replace the mbed lib btw, it is the same for all devices (and includes proper code depending on which device you select). You generally do need to update it, since most will be from before Nucleo support. Click on the mbed lib, click update at the right side.

Debugging wise I have always simply used printf statements, but they also feature real debuggers, for that you need to export the code to an offline toolchain, and then run the debugger like usual (no idea personally what usual is, but there are some tutorials here, and otherwise on the interwebs, since it is same as debugging otherwise is for those devices). But you can get quite far with just using printf to see where it hangs for example, why, etc.

Finally, the DS18B20. Wish I knew about that one when I required one, looks better than some others. Since it only seems to read '1's I would guess the pull-up works fine, but it is never pulled down. You do have a proper resistor? Something like 1k at least, not that it is a 40 ohms resistor. That library cannot handle parasitic power (although it shouldn't matter when reading Serial Number), so the power pins should be connected to VDD. Your ground is properly connected to a ground pin? And of course data pin goes to your PC_4 pin actually?

10 years, 8 months ago.

Thanks very much for your help.

Ok I'll stick with debugging on my lcd, every time I update my code I lose my com port to mbed terminal connection, and it's a pain resetting it each time.

Ok I've had another go with the DS18B20. I've got two more on the way in case this one is a dud or somehow I've cooked it.

I've got 5v across my Vcc and GND (both straight to the mbed), and when I disconnect the DQ my program stops working. I've got a 1k resistor in line as well now, I had missed that before. I've also tried 4700 and 5600 ohm as per the datasheet. I don't seem to be reading it properly, everything returns 0xFF, even the temperature it seems.

I'll have another go with the HC-SR04 and see if I get any further with that, thanks :)