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STLINK V3 - is it supposed to be 100% reliable?

PHolt.1
Senior III

I have just moved from ST-LINK/V2 ISOL to STLINK-V3SET. Win7-64. 24GB RAM. A very stable machine and I have two identical ones.

The reason for V3 was to see if the SWV ITM debug mode was more reliable (or occassionally loses a byte or so), and I read somewhere that V3 is much faster.

Well, V3 is much faster. Code download has gone from a few seconds (~200k) to something so fast I can barely see it. This is worth having especially in a production environment, and especially at 24MHz (which is what it turns out to use if you select Auto)

But it isn't all that reliable. After some minutes Console says it has lost contact. At 8MHz it seems to be more reliable but only sometimes. I guess the quality of the wiring comes into it... I have about 30cm which is 20cm ribbon cable and 10cm single wires to my PCB. But even 8MHz is not 100% reliable. It is much better on one PC than another. All speeds are 100% reliable for code download (well, it always reports as having verified) but in the long run with debugs it does eventually bomb out. I tried the debugger at 1MHz instead of 2MHz but it makes no difference.

I am using SWV ITM debug because it is very fast.  I did a printf("1234567890") and timed the gap with a scope between two pulses generated before and after.

SWO debug / SWV ITM data console: 6-20us

Dynamic Printf / debugger console: 120ms!

Should I just accept that this stuff is a bit flakey and live with it? STLINK-V2 was solid in terms of the connection to the debugger, whereas V3 eventually loses the connection.

If anyone can suggest anything else for me to try I would be very grateful.

The other modes in the screenshot e.g. JTAG do not work, which is weird since JTAG is what this whole thing is supposed to be using. Only SWD works. The target connections are

JT-SWCLK

JT-SWDIO

NRST

JT-SWO

JT-NJTRS (no connect)

https://peter-ftp.co.uk/screenshots/20210420163062416.jpg

13 REPLIES 13

USB hubs can be tricky and not all of them created equal. Read this for example: http://www.yoctopuce.com/EN/article/how-many-usb-devices-can-you-connect

--pa

and sometimes whether the hub is powered or not makes a difference ...

PHolt.1
Senior III

I have just got a 3rd STLINK V3 SET. Even if it flakey, it is a lot faster running through breakpoints.

Interestingly, the bit of paper in the box says USB 2, not USB3, is supported. Well, it would be: it has a micro-USB port which is only USB2.

PHolt.1
Senior III

Is there any doc stating the max speed of the ISOL board?

It doesn't work at all at 24MHz but works at 8MHz.