What SWD/ISP/JTAG to use with STM32F407?

[LMI2]

Posted on September 24, 2016 at 00:16

I am building a testboard with a 100pin 407VGT in it. There is no room for USB on it. After reading the HW manual I still don't know what is a correct/best programmer connector to use.

There are 6 pins in Discovery boards I have, but there is no cable for 6 pins in a line I think.

I have a professional looking USB dongle from China. It has text ST-LINK V2. It has a 10 pin connector. It is connected as follows. RST, SWCLK, SWIM, SWDIO, GND, GND, 3.3V, 3.3V, 5.0V, 5.0V. It works, but requires a handmade adapter with 5 pins.

What is the best pinout of the most used or best programming connector.

[Tesla DeLorean]

Posted on September 24, 2016 at 00:37

For JTAG/SWD we use the standard ARM 10-pin connector

http://www2.keil.com/coresight/coresight-connectors/#10pin

Use a standard foot-print, it gets really old, really quickly, having to remember and remake connectors for everyone's special configuration.

If you use push-pins in the test fixturing you could arrange your own test-points or leave unpopulated land patterns. Put them on the bottom of the board, or wherever works best for production, remember debug/dev is a fractional use case.

We would at minimum provide SWDIO, SWCLK, SWO (PB3), NRST, GND, we like the SWV (Serial Wire Viewer) for debugging, and the reset also provides a means to wrestle control. Full JTAG if you boundary scan, or have other chips on-board.

All manner of people use assorted pin headers, like ST with the evolving DISCO connector, or the half-dozen bootleg ST-LINK type devices you see on eBay. You could expose the debug/programming header on edge castelations of the board in things are tight.

I'd also recommend providing access to BOOT0 and USART1/3 RX/TX, along with NRST, GND and perhaps power, to provide access to the System Loader ISP. Serial is very low cost and low complication compared to JTAG/SWD

[LMI2]

Posted on September 24, 2016 at 00:54

Thank you. I found the pins of the connector from CPU too, except one. What is VTref and where it should be connected?

[Tesla DeLorean]

Posted on September 24, 2016 at 01:26

It should be your Target Voltage, ie whatever you are running the STM32 at, so 2.8V, 3.0V, 3.3V, etc. The pod isn't providing this, it is using it.

You have this on the connector to power the voltage level converters on the debug pod. The stand-alone ST-LINK has buffers on the IO pins so it can work with a wide range of chips/boards. The on-board ST-LINK on the NUCLEO/DISCO boards don't have these as they have a common 3V supply.

[LMI2]

Posted on September 24, 2016 at 01:43

Ah. The forum is working again.

Ok, I got the pinout now. FYI, I ordered also sample 407 chips.

From: clive1

Posted: Saturday, September 24, 2016 1:26 AM

Subject: What SWD/ISP/JTAG to use with STM32F407?

It should be your Target Voltage, ie whatever you are running the STM32 at, so 2.8V, 3.0V, 3.3V, etc. The pod isn't providing this, it is using it.

You have this on the connector to power the voltage level converters on the debug pod. The stand-alone ST-LINK has buffers on the IO pins so it can work with a wide range of chips/boards. The on-board ST-LINK on the NUCLEO/DISCO boards don't have these as they have a common 3V supply.